Author: Pavel Alexe

T-72 Ural-1 in Romanian Service

Post author By Pavel Alexe
Post date December 12, 2022
11 Comments on T-72 Ural-1 in Romanian Service

T-72 with fish gill sideskirts. Illustration by Pavel Alexe based on work by David Bocquelet.

Socialist Republic of Romania/Romania (1978-2005)
Main Battle Tank – 31 Purchased from USSR

Romania is relatively well-known for its own tank development projects, such as the TR-85-800 and TR-77-580, the latter entering production in 1978. Yet, just the previous year, after increasing pressure for rearmament for the Warsaw Pact members, the Socialist Republic of Romania purchased 31 T-72 Ural-1 tanks, partially to use as an ‘elite’ battle tank, but most importantly, to use for its own tank development program – the TR-125. The T-72 in Romanian service spent most of its time in absolute secrecy. They were first seen in the December 1989 revolution, where even other Romanian tankers thought it was foreign, and allegedly fired upon them. After the Revolution, they would see regular service alongside other tanks. They were retired prematurely in 2005 with great controversy. They have since disappeared, last time being seen in a degraded state in 2014. One T-72 remains in public view at the King Ferdinand National Military Museum in Bucharest.

One of the 5 T-72s at Pitesti during a parade, 2009.
Source: Resboiu

Background

In the mid-1970s, the Socialist Republic of Romania sought to upgrade and modernize its weapons arsenal massively, partly from purchasing vehicles from the USSR, partially from license production of both Eastern and Western products. A new main battle tank (MBT) was a priority. At the time, Romania only had T-34-85 and T-55 tanks in service, as well as its own tank development program, which would result in the TR-77-580, with production starting in 1978.

This rearmament plan was partly triggered by Commander-in-Chief of the Warsaw Pact and Marshal of the Soviet Union Ivan Yakubovsky, who claimed:

“Every military should have its own units equipped with the most modern types of armament and military technology, for the timely training of ranks for new equipment and gathering experience in using and mastering the equipment.”

To put Soviet Marshal I. Yakubovsky’s idea in practice, in April 1977, Romanian Minister of Defence, General-Colonel Ion Coman, at the alleged indication of Secretary General and leader Nicolae Ceaușescu, sent a letter to the Soviet Minister of Defence Marshal of the Soviet Union, D.F. Ustinov, about the purchase of a battalion of new T-72 tanks. The request was approved by Ustinov, and on 30 August, Ion Coman would send a letter to Ceaușescu stating that the order for 31 T-72 Ural-1 tanks was approved by the USSR.

General-Colonel Ion Coman, Minister of Defense between 1976 and 1980. He would be stripped of his military rank and sentenced to 20 years in jail at a trial in 1991 for his actions in the Revolution.
Source: MApN

Between 1978 and 1979, the Socialist Republic of Romania purchased 31 T-72 tanks from the USSR, in a contract worth 150 million Lei ($12.62 million dollars in 1979, around $52 million in 2022). The contract also included maintenance, ammunition, and troop training costs, and a ‘dummy’ tank for training.

The first T-72 tanks were delivered in 1978 to the 1st Tank Regiment “Vlad Țepeș” (Vlad the Impaler). Although they were produced in 1978, the tanks were not brand new, and had been used either in quality tests or exercises, as spent shell casings were found inside, spare parts and auxiliary tools were used, as well as there being a handful of kilometers on the board. In addition to the 31 functional tanks, Romania also acquired a simulation and training vehicle (no armor and static) as well as extra turrets (used for the TR-125 development).

T-72 Ural-1

In the late 1960s, Factory No.183, Uralvagonzavod (UVZ) would develop its own T-64 upgrade out of its own initiative. The main goals were to be cheaper, simpler, and more reliable than the T-64, allowing for easy mass-production, while still using the main advantages of the T-64. It used many turret and hull components of the T-64, as well as the D-81 125 mm gun. It was equipped with a V-45 780 hp engine, requiring a longer hull than that of the T-64. In January 1968, after its completion, it was named Object 172. In 1971, an improved version was made, using the lower hull and running gear from the Object 167, becoming the Object 172M.

It entered service in 1974 with great controversy. Many saw it as a waste of resources. For example, UVZ factory director I.F. Krutyakov put it as a “tactical mistake”. But the need of replacing the T-55 with a new MBT was growing, and the T-72 would end up being produced at 4 factories and becoming one of the most influential, mass-produced, and iconic MBTs of the Cold War, with countless variants, exports, and uses in combat.

The T-72 featured an 125 mm 2A26M gun with a 22 round carousel autoloading system (an extra 17 rounds were stored outside the carousel), needing just 3 crewmembers, commander, gunner, and driver. Secondary armament consisted of a 7.62 mm PKT coaxial machine gun and a 12.7 mm NSVT anti-aircraft machine gun. Armor (for the early variants) consisted of an upper frontal plate angled at 68º with 80+105+20 mm thick plates. The cast rounded turret was 410 mm thick. Later models would employ various types of ERA and add-on armor, as well as many adjustments to plate thickness and materials.

In December 1975, an upgraded variant of the T-72 would enter service as the T-72 Ural-1, developed at UVZ under leadership of V.N. Venediktov. It differed from the base T-72 models with improved armored protection, thermal sleeve on the gun barrel, and an infrared searchlight to the right of the main gun. In total, 5,250 such tanks would be produced between 1976 and 1980.

Romanian T-72 Ural-1 with its ‘gill’ armor still in place, early 2000s.
Source: Lt. Col. I.Trofimov

Operation – the 1st Tank Regiment “Vlad Țepeș”

The city of Târgoviște was arguably one of the best geographical area for a tank regiment, north of the Muntenian plains and south of the Carpathian mountains. The geographical-strategic advantage of the city had been well-known long before, having served as a capital for Wallachia (Valahia/Țara Românească) between 1396 and 1714. At the beginning of the 20th century, there were proposals to move the capital of Romania to Târgoviște, especially since there was only a 80 km distance between it and Bucharest. In 1872, a cannon factory was built there, which would later act as a maintenance center for artillery, known as Arsenalul Armatei (Eng: The Army Arsenal).

On 6 December 1919, after just 2 months of existence at Giurgiu, the first Romanian tank regiment was moved to the Târgoviște garnison. A year later, after a decree by King Ferdinand, the first Romanian Tank Regiment was created, Regimentul Care de Luptă (Eng: The Battle Tank Regiment) taking effect on 1 January 1921, consisting of 2 tank battalions. In the 1930s, the regiment increased to 3 battalions, receiving new Renault R-35 and Škoda R-2 tanks. In 1939, after a second tank regiment was formed, the Târgoviște regiment was renamed to Regimentul 1 Care de Luptă (Eng: Regiment 1 Battle Tanks). During the Second World War, the regiment, under the 1st Armored Division, fought against the Soviets in the liberation of Bessarabia (Basarabia) and Northern Bukovina (Bucovina), as well as the offensive into Odessa and Stalingrad. After the 23 August 1944 switch to the Allied side, the regiment would defend Transylvania and fight into Hungary, Czechoslovakia, and Austria. In 1974, the regiment was renamed 1st Tank Regiment “Vlad Țepeș”.

Renault FT tanks of the Romanian Tank Regiment in Bucharest, 10 May 1925.
Source: Trupele Blindate din Armata Romana 1919-1947

The T-72 Ural-1 tanks were kept under utmost secrecy and incorporated into their own, independent tank battalion, which was isolated from the rest of the regiment, with exercises and training being done separately. Access to the training polygons was prohibited to members of other units, such as other tank, infantry, and artillery units from the base. Access to the tank facilities could only be done by the tank battalion members, who required a special permit. The unit’s members themselves were recruited after several checks to prove their loyalty to the party and trustworthiness.

The T-72 battalion was very well equipped for Romanian standards. The T-72 tanks were housed in a specially built ventilated warehouse, allowing to run the engines inside. Their unit included a specific “tancodrom”, a training area specially designed for various tank exercises and training, railway with loading platform directly in the barracks and tank storage area, firing range, water crossing and fording trench, ammunition depot, and training halls.

The tanks were kept secret until the Revolution of 1989. The tanks had not been shown to the general public or even other tankers since their introduction. Few tank officers ever got the chance to see them. Former commander of the 1st Tank Battalion “Vlad Țepeș” and blogger, Lieutenant-Colonel Ifrim Trofimov, has written a series of blog posts covering his experiences with the tank. He describes seeing the T-72 for the first time, after being a tanker since 1978 on both the T-34-85 and T-55:

“In 1984, when I was at a company commander training course, in Făgăraș, I saw it for the first time.

It was on a trailer, towed by a Tatra truck, covered by a tarpaulin. Even though we were tens of tank officers, many of us being company commanders, we were not allowed to see it, satisfying ourselves with its silhouette, and whatever we could see from under the tarpaulin: tracks, roadwheels and the gun barrel.”

Czechoslovakian TATRA 813 prime mover transporting a T-55AM, early 2000s.
Source: Lars Erik Salo via Pinterest

The T-72 ‘dummy’ rig for maintenance and technical training.
Source: Lt. Col. I.Trofimov

At the beginning of the 1980s, just a few years after the T-72 was purchased, Interarms attempted to purchase 2 such tanks from Romania. Interarms was a company based in London, claiming that they were willing to purchase armament, equipment and ammunition worth $22 million for a state in the Persian Gulf region. Romanian officials realized that the T-72 tanks were the actual target and that they would end up in the US. The contract did not go through.

T-72 at the Revolution – Petty Combat

During the Romanian Revolution, the military was called in to Bucharest by then Minister of Defence Vasile Milea to defend the Communist regime from the anti-regime protesters in the streets. The following regiments were called in:

Bucharest 1st Mechanized Regiment (equipped with TR-85-800s)
Bucharest 20th Tank Regiment
Caracal 68th Tank Regiment (equipped with T-55s)
Târgoviște 1st Tank Regiment (equipped with T-72s)

The Caracal 68th Tank Regiment was in the midst of switching from the T-55 to the TR-85-800 when the Revolution began. The Caracal regiment was called in to Bucharest on 19 December and were to equip wartime munitions. Choosing the T-55 tanks over the TR-85-800s, according to a platoon leader, 50 tanks (64 according to other veterans) drove the nearly 200 km with a speed of “no less than 40 km/h” and with “sparks coming from our tracks”.

Prior to entering Bucharest, Major Marchiș had told the tankers, “Warning. From this moment, there’s death! There’s shots, we don’t know from where, there are terrorists, we can always have surprises!”

The unit moved slowly towards the Palace Plaza, but was ordered to defend the Ghencea ammunition depot, as allegedly tanks captured by the “terrorists” were approaching it and wanted to blow it up. Naturally, the tankers from 68th Tank Brigade were not informed about what troops were already in, or about to enter Bucharest. Unfortunately, as the 68th Tank Regiment spent most of its time in Ghencea, on the outskirts of Bucharest, there are no period photographs of their T-55 tanks.

T-55 of the 20th Tank Regiment at the Palace Plaza, in front of the Central Committee of the Romanian Communist Party, after the military had joined the fight against Ceausescu alongside the population.
Source: Mediafax

According to the historical register of the Târgoviște regiment, it was called in towards Bucharest on December 22 at 20:20, with a tank column ready for march in 10 minutes. Part of the tanks were to be under command of the 1st Army, and part in direct command of the MApN headquarters. On 23 December, the tanks were searching the areas in Bucharest where “terrorist activities” had been performed, at the request of the MApN. When, at the Northern Station (Gara de Nord) the column was attacked and dispersed, the tanks lost communication between each other. Towards the evening, the tanks were ordered towards Ghencea cemetery to “destroy the terrorist group from the cemetery”. Here, 3 tanks opened fire at a house next to the cemetery. An unnamed tank officer, which had previously been at the construction of the Casa Poporului (Ceaușescu’s large palace), had contacted one of the officers from the tank regiment as to why they were firing upon the house and advised them to stop. In an attempt to convince himself and the tankers that there was no danger, the man went to the house, where he discovered on the other side of the street, 3 TAB APCs with several soldiers in firing positions. The 3 TABs were firing upon the same house as the Târgoviște tankers had. He convinced them to stop, as they were at risk of hitting the tanks on the other side. He was hit in the chest by bullets shortly after and taken home by a civilian for care.

As virtually nobody had seen a T-72 in Romania before, including officers, these were thought at first to be the foreign or “terrorist” tanks. News had already spread about Soviet tanks on the eastern border and the threat of Soviet regular forces entering the country. Other false news, both from media and from civilians, about terrorists with unknown tanks appearing out of nowhere came to the tankers.

Two T-72 tanks from the Târgoviște Regiment in central Bucharest on Christmas Eve 1989. Note that the muzzle cover is still on.
Source: Cartula

Thus, the inevitable happened. On the 24 December 1989, in the first tank-on-tank combat of the Romanian Army since the Second World War, a single (or several, considering the amount of shots fired) T-55 from the 68th Tank Regiment opened fire on a T-72, the tank crew likely not recognizing the T-72 tank type. Thankfully, the T-72s were not equipped with live ammunition (of which there was very little, as it was the only unit to operate the 125 mm gun). Consequently, the T-72 crew attempted to drive away. The tank was struck in the engine bay, but the automatic fire extinguisher system prevented any disaster and the crew was able to exit the tank. The action was recalled by retired Deputy Sergeant Marin Oane from the 68th Caracal tank regiment in an interview:

“We fired upon that tank, it was said that it had been captured by the terrorists and came to blow up the (Ghencea) depot. They were actually our colleagues from Târgoviște.”

The tank combat story, according to the Târgoviște regiment historical register, was slightly different. On 24 December, a T-72 was struck by a TR-85-800 from the 1st Mechanized Regiment and 3 other T-72s acted to deter the attack. However, in the detailed memoirs of General Marin Oană (Lieutenant-Colonel of the 1st Mechanized Regiment) about the actions during those days, he does not mention of any contact with tanks from the 1st Tank Regiment.

At an unclear date, the T-72 tank was recovered and sent to Mizil for repairs. At the installations, Ifrim Trofimov was able to get a look at the damage done. In total, 5 (4 according to the unit commander at the time) shots had hit the T-72 (in unknown order):

Shell 1: Likely an HE-FRAG, exploded on impact with the antenna mount, melting the antenna and scraping off the paint.
Shell 2: Also an HE-FRAG, hit the right rear fender, damaging it and bursting an external fuel tank.
Shell 3: Also an HE-FRAG, hit the left side of the rear armor plate, denting it.
Shell 4: A BK-412 AP- HEAT round penetrated the tank, right at the welding between the rear plate and the left sidewall. The cumulative molten jet had penetrated the armor and entered the engine compartment.
Shell 5: Also a BK-412 AP-HEAT, penetrated through the exhaust and into the engine compartment.

One of the most iconic and cinematic pictures of the Romanian revolution. This T-72 has several civilians on its engine deck, sometime between 22 and 25 December 1989.
Source: Ullsten bild – Reuters

Post-1989 & Dissolution

After the Revolution, between 1992 and 1995, the unit was reorganized by the C.S.A.T. (Supreme Council of National Defense). Firstly, the T-72 tanks were no longer a secret, and would be incorporated into a complete tank battalion, with 30 T-72s and 10 T-55AM2s, renamed to the 1st Tank Battalion “Vlad Țepeș”. The new organization, which was applied to all tank units, was as follows: a tank platoon had 4 tanks, a tank company had 13 tanks (4 platoons of 3 tanks each plus a command tank), while a tank battalion had 40 tanks (3 companies of 13 tanks each and one battalion command tank). A single tank battalion was part of a mechanized regiment. The Târgoviște Regiment had an additional 108 tanks, 12 SU-100 SPGs, as well as various APCs, Malyutka-equipped BRDM-2s, and more.

As Romania was preparing to join NATO, the military underwent drastic changes. Many systems and equipment had been retired and subsequently scrapped or sold off. Romania’s military would change its military from a massed conscript force to a professional Western-style army. Concerning the tank forces, this meant that Romania would only have 5 tank battalions.

Signs that the T-72 would be phased out came as early as September 2001, when live-fire training of tankers would be done on TR-77-580, after training on the T-72, which it operated. Worthy to add is how different the 2 tanks were, as the TR-77-580 had a manually loaded 100 mm gun, as opposed to the autoloading 125 mm gun of the T-72.

Structural changes were implemented in June 2002, with the entire regiment being decreased in size and structural and bureaucratic functions removed. During the same period, the new TR-85M1 (upgraded TR-85-800) was supplied, and crews began training on it.

In 2004, the C.S.A.T. officially disbanded the 1st Târgoviște Battalion, ending an 86 year old tank tradition at the Târgoviște garrison. In January 2005, the tanks were transported away on flatbeds, 5 sent to Pitești and the remaining 25 sent to a storage facility in Voluntari, northern Bucharest. From there, they ended up in the yard of the UMB factory (Uzina Mecanica București), where the last picture of them was taken in 2014. They have since disappeared.

Memorial plaque with the names of the commanders of the 1st Tank Battalion “Vlad Tepeș”, 1957-2005.
Source: Lt. Col. Ifim Trofimov

Why the T-72 tanks were taken out of service remains a mystery, with no official answer ever given. Lt. Cl. I. Trofimov, who was assigned battalion commander of the troublesome T-72 battalion in 2001, blames it on the stupidity of higher-ups, an idea slung around far too often both in terms of Romanian military and industry. According to him, in 2005, when the tanks were sent away for storage, they still had 6 spare guns, 21 unused engines, and a host of spare parts. In contrast, according to other sources, the number of usable tanks decreased rapidly in the last few years of service. Allegedly, 28 were functional in 1995. By 1998, it dropped to 15, and in the 2000s, as low as 12. Why they were not repaired with the aforementioned abundance of spare parts remains a mystery, though funding and lack of skilled mechanics on the tank and specific systems could have been an answer.

By joining NATO in 2004, Romania broke its already dwindling relations with Russia, and any hopes of securing further spares, and most importantly, ammunition, were gone. This explains why there were no longer any firing trials with the T-72’s main gun. With little ammunition left, the remaining stocks were saved for potential use in combat, and ultimately, the tanks were no longer worthy of active use and training. Consequently, the tanks were withdrawn from service with the 1st Tank Battalion “Vlad Țepeș”. By the 2010s, 29 (remaining one was sent to the King Ferdinand Military Museum) T-72 tanks were listed up for sale by Romtehnica, the defense trading company of the Romanian Ministry of Defense.

The T-72 at the King Ferdinand National Military Museum in Bucharest. Note the larger TR-125 (P-125 to highlight that it is a prototype) to its right.
Source: Author’s collection

In spring 2022, with the Russian invasion of Ukraine, there were rumors on social media about Romania donating its remaining T-72 tanks to Ukraine. While Romania has shipped over $3 million worth of gear, ammunition, and provisions, heavy equipment, such as unoperational T-72s, have never been considered publicly, although some Romanian-produced TAB-71Ms have appeared in Kherson. If these tanks still exist and were not scrapped or sold by 2022 is up to question.

At least 11 T-72 tanks rotting at UMB Bucharest in 2014. They have since been removed.
Source: Victor Samartinean

114th Tank Battalion “Petru Cercel”

On 1 October 2009, the C.S.A.T. would reinstate armored forces in Târgoviște, with the creation of the 114th Tank Battalion “Petru Cercel”. However, the Battalion would be equipped with 54 aging T-55 and T-55AM/AM2 tanks, essentially replacing a T-72 battalion with a T-55 battalion over a period of 5 years. The Battalion is active to this day.

Detachment of 3 T-55s and a T-55AM during the ARGEDAVA 21 exercise, 2021.
Source: MApN Facebook

TR-125 (P-125)

After the Soviet invasion of Czechoslovakia in 1968 and Ceaușescu’s heavy criticism of it, Romania’s military attempted to decrease its reliance on Soviet weapons imports, and turned towards Western countries for patents and technology. In terms of tanks, this meant the development of the TR-77-580. Based on the Soviet T-55, it saw improvements on paper, but, due to Romania’s lack of experience in the field, had several production and technical issues. Shortly after, in 1986, the TR-85-800 would begin production. Largely based on its predecessor, it saw major improvements, such as an 800 hp engine, reverse engineered from the German Leopard 1.

After Romania purchased the T-72 from the Soviets, it intended to locally produce it as well, just like the Yugoslavs had done with the M-84. A production patent was requested, but it was not granted by the Soviet government. Thus, Romania began reverse engineering the T-72, in what would become the TR-125. The T-72, and in turn the TR-125, were meant as a sort of “elite” battle tank, operating independently and in significantly fewer numbers to the T-55s, TR-77-580s, and TR-85-800s. However, due to the fall of the Communist regime and in turn Cold War, massive military budget cuts and privatization of many enterprises sentenced the TR-125 project to a slow demise. Recognizing that the TR-125 was clearly obsolete as a new MBT by the 90s, in the 2000s,the TR-2000 program was born. Several new tank models would be designed with the help of Krauss-Maffei and their components, while keeping the TR-125 as a basis. The project was too expensive and cancelled. Instead, the TR-85-800 were upgraded to the NATO-standard TR-85M1.

One of the 10 TR-125 prototypes, now exhibited at the King Ferdinand National Military Museum in Bucharest.
Source: Flickr

Type 64

During the many Sino-Romanian armament negotiations, the Chinese were able to learn that Romania had purchased 31 T-72 tanks from the USSR. This move fit the Chinese interests very well, as they had been searching for Soviet T-72s to be able to develop a new generation of MBTs. The Chinese offered fighter jets (likely of Soviet origin) or Harbin H-5 bombers and tank maintenance equipment in exchange of 1 T-72 Ural-1. Whatever the final offer was, the Romanians accepted and the tank was dismantled on Romanian soil, packed into containers and shipped to China. The tank was given the codename Type 64. The vehicle was reassembled without technical instructions in China and tested significantly. With information gathered from it, the Chinese were able to develop a new generation MBT, the Type 96 (Type 96). The vehicle is now somewhere in Inner Mongolia, China.

The Type 64 in more recent years. Note that the ‘gill’ armor and 12.7 mm NSVT machine gun have been removed.
Source: Voodoo_Six_one via WT forums

Conclusion

The T-72 was one of the most iconic MBTs of the Cold War and remains widely used to this day. Romania purchased 31 such tanks from the USSR in the late 1970s and kept them under extreme secrecy until the 1989 Revolution. Since then, the tanks operated normally all throughout the 1990s, until it was decided to remove them from service, arguably prematurely, and send them into storage. The Romanian T-72s were also crucial in the development of Romania’s own tank program, in the form of the TR-125, but also the sale of a single model to China, which renamed it Type 64 and triggered their Second Generation MBT development.

T-72 as seen during the Revolution. Illustration by David Bocquelet.

T-72 with fish gill sideskirts. Illustration by Pavel Alexe based on work by David Bocquelet.

T-72 Ural-1 in Romanian service specifications
Dimensions (L-W-H)	9.53 (incl.gun) – 3.59 – 2.23 m
Total Weight, Battle Ready	41.5 tonnes
Crew	3; commander, gunner, driver
Propulsion	780 hp diesel, V-12 config.
Speed	～60 km/h
Armament	125 mm 2A26M autoloader 7.62 mm PKT machine gun (coaxial) 12.7 mm NSVT machine gun (roof-mounted AA
Armor	UFP angled @ 68 deg. 80+105+20 (mm) Frontal turret: Ca. 410 mm Side turret: Ca. 210 mm Side hull: 80 mm Hull deck: 20 mm Hull belly: 20 mm
Total Purchased	31 purchased + 1 training dummy

Sources

Trupele Blindate din Armata Română 1919-1947 – Cornel I. Scafes, Horia V. Serbanescu, Ioan I. Scafes
Buletinul Arhivelor Militare Române Nr.90 2020 – Petre Opris
tROfi: Despre T 72-ul dâmboviţean (1) (trofi53.blogspot.com) – Cl. (r) Ifrim Trofimov
Organizarea unitatilor de tancuri in Armata Romana – Romania Military (rumaniamilitary.ro) – Cl. (r) Ifrim Trofimov
https://www.rumaniamilitary.ro/realizarea-tancului-tr-125#prettyPhoto Cl. (r) Ifrim Trofimov
rechizitoriu_revolutie_2d8cab0025.pdf (realitatea.net) – (july 2022) Cl. Magistrate Cătălin R. Pițu
“>T-72 “Ural-1” – December 15, 1975 (livejournal.com) – Andrei BT
Object 172M | Tank museum Patriot park Moscow
Amintiri din decembrie ’89: „Dacă n-am încălecat la morţi de m-au găsit loazele, mi-era nu ştiu cum să-i calc cu şenila“ | adevarul.ro – Alina Mitran
Cum a devenit Târgovişte punct nevralgic pe harta militară a Europei. Fabrica de tunuri a lui Cuza şi intervenţia imperativă a Rusiei ţariste | adevarul.ro – Corina Slamnoiu
Amintiri din ’89. Sute de militari au primit alarma „Radu cel Frumos” | Digi24

WW2 Soviet Heavy Tank Prototypes

IS-M (Shashmurin)

IS-M as illustrated by Pavel Alexe, funded by our Patreon campaign.

Soviet Union (1944)
Heavy Tank – Drawings Only

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Just months after the IS-2 began production, work began on developing a new heavy tank to replace it down the line. Engineer N. F. Shashmurin and his team envisioned an unusual tank, meant as a direct IS-2 upgrade, the IS-M. The most notable aspects of Shashmurin’s design were the large-diameter road wheels and the rear mounted turret. However, his project was not taken into consideration and was short-lived, although it did pave the way to the IS-6, which used some of its features.

The IS-M model as represented in Wargaming’s game World of Tanks
Source: World of Tanks

Shashmurin and the IS

Tank designers are usually overlooked in the popular imagination, and those few acknowledged are usually limited to the likes of Ferdinand Porsche or Alexander A. Morozov. Even when limited to Soviet heavy tanks, the names of Nikolai L. Dukhov and Joseph Y. Kotin overshadow the others. Yet Nikolai Fedorovich Shashmurin was the man behind the creation of one of the USSR’s greatest war-winning tanks, the IS-2.

Born in 1910 in what at the time was called St. Petersburg (to be renamed Leningrad in 1924), Nikolai Fedorovich Shashmurin started his engineering studies at the Leningrad Polytechnic Institute in 1930 and graduated in 1936. By 1937, he had started to work at LKZ (Leningrad Kirov Plant) as an engineer for the SKB-2 design bureau. Before the war, he would work on the T-28 medium tank and create the torsion bar suspension system (T-28 No.1552) fitted on the SMK and U-0 (first KV-1 prototype), a system which would be implemented further on all future Soviet heavy tanks and self-propelled guns. Additionally, he developed gearboxes for the KV-1 (his gearbox would be dropped in favor of Dukhov’s infamous gearbox which would haunt the KV-1 for its entire service life), KV-220, KV-3, and even his own design for the KV-4 program.

N.F. Shashmurin in the 1930s.
Source: Bronetechnikamira.ru

With the beginning of the German siege of Leningrad in 1941, the LKZ (Leningrad Kirov Factory), specifically SKB-2 engineers, were evacuated to ChTZ (Chelyabinsk Tractor Plant) in Chelyabinsk (near the Ural Mountains), renamed ChKZ (Chelyabinsk Kirov Plant) a few weeks later. At Chelyabinsk, Shashmurin would develop the gearbox of the KV-1S and, after N. V. Tseits’ death in summer 1942, he became the head engineer for the KV-13 (at the time called IS-1), a vehicle which he did not like. Nonetheless, he would build upon it, and by May 1943, he had designed a new variant, equipped with an 85 mm D-5T gun specifically for the task of penetrating the German Tiger I, mated to a new hull. This was the Object 237 (at the time named IS-3), which would be adopted in service in September 1943 as the IS.

In parallel, Shashmurin designed the Object 238, meant to fit the new 85 mm S-31 gun in the KV-1S, but it was unsuccessful due to the cramped conditions within the turret. Production of the IS-1 started in November of that year, but it would not last long, as, by May 1943, work began on fitting the IS with the 122 mm D-25T gun, and by December 1943, the Object 240 would enter service as the IS-2. The mounting of such a powerful high-caliber gun was unprecedented in Soviet heavy tanks, which normally had similar, if not the same, guns as medium tanks.

Improving the IS-2

Extensive testing of the IS-2 was done at the NIBT (38th Research Test Institute of Armored Vehicle) proving grounds at Kubinka in January and February 1944, where it was concluded that the armor of the tank was not sufficient. Most notably, the “stepped” frontal hull was considered a weak spot, and it was proposed that the frontal hull should be made out of one angled plate.

IS-2 during testing at NIBT, January/February 1944. Note the 122 mm D-25T gun with the German-style muzzle brake.
Source: Warspot

The NiBT proving grounds’ proposal to change the shape of the frontal armor of the IS. Note the old shape in the non-continuous line.
Source: Yuri Pasholok

IS-2 with sloped frontal plate, as originally proposed by NiBT proving grounds and Shashmurin in 1944. The sloping is similar to that on the IS-M.

Even after the first IS combat engagements, it became clear that, with the introduction of the German Panther tank, armed with a 75 mm KwK 42 L/70 (which could pierce the frontal armor of the IS heavy tanks) that the IS was insufficient. As early as September 1943, General Fedorenko (Head of the Armored Vehicle Directorate of the Red Army) would send a letter to Stalin, requesting the thickening of the IS armor and increasing its weight to 55-60 tonnes.

Additionally, in November 1943, the technical requirements for a new heavy tank were set by the GABTU (Main Directorate of Armored Forces). It was to have a mass of 55 tonnes, crew of 5, 160-200 mm of armor(frontal turret and hull), 800-1,000 hp engine, and a 122 or 152 mm gun. Speed was to be at least 35 km/h. These requirements would be laid down at the ChKZ plant on 3 December (10 December according to other sources) by factory director I.M. Saltzman.

The ChKZ SKB-2 design bureau, headed by N.L. Dukhov, had already worked on a new heavy tank since July, with its own funds. It was the 56-tonne K tank. The project was named Object 701.

However, on 21 March 1944, the GABTU changed the technical requirements. The weight was lowered to 55-56 tonnes, armament was a 122 mm gun with a muzzle velocity of 1,000 m/s, and 30 to 40 rounds had to be carried. The engine was to have a 1,000 hp output and allow for 40 km/h top speed. Armor thickness was not specified, instead, it was to be immune frontally to the Panther’s 75 mm KwK 42 L/70 and the 88 mm PaK 43/2 L/71 of the Ferdinand/Elefant.

These changes forced the reworking of the existing Object 701, but a green light was given the same month to produce 2 prototypes, leading to the IS-4 tank’s long development, with the first prototype, the Object 701-0, being built in May 1944.

The Object 701-0, the first prototype of what would become the IS-4.
Source: Supertanki Stalina IS-7

At the same time as the developments at SKB-2, the other design institution at ChKZ, Factory No.100, also worked on their own tanks based on the same requirements. Headed by J.Y. Kotin, their approach was different to that of SKB-2. Instead of designing a new tank, they focused on a deep modernization based on the IS-2. By 18 April 1944, Factory No.100 would present its initial designs. Again, 2 models were built, one with a frontal plate separated into 3 parts (as on the first K tank) and one with a UFO-shaped hull, akin to the Object 279, designed and built decades later. Despite the increased protection, both variants had the same weight as the IS-2, 46 tonnes.

Factory No.100 April design of an upgraded IS-2. Note the UFO-shape hull and large road wheels.
Source: Supertanki Stalina IS-7

The 2 models designed by Factory No.100 on either side of an IS-2 tank model.
Source: Warspot

A document dated 8 April 1944, ordered J.Y. Kotin and his team to develop an upgraded variant of the IS-2 and subsequent SPGs over a 3-month period. The improvements should have included, but not been limited to, strengthened the armor protection, transmission, and chassis.

This would likely trigger the development of a new IS-2 modernisation, based on the requirements from 21 March. The design was to be less ‘radical’ and closer to the IS-2, but some very big changes were made. The tank would be called the breakthrough tank IS-M, the M standing for модернизация, meaning ‘modernisation’.

Sources do not agree exactly when development started, some arguing March, whereas others early April 1944. Nonetheless, N.F. Shashmurin was head of the project. While some design elements were taken from the previous upgraded designs, the main change was moving the turret to the rear of the hull, creating a very unique tank. A drawing of the tank would be made by Dobrovolsky. Who he was is so far unknown.

Design

The design of the IS-M was peculiar and unorthodox. The entire upper hull was made from several stamped steel plates, slightly angled inwards, with both the front and rear angled heavily. These were welded to the lower hull, which, while still mostly flat, had angled corners for extra weight saving. In addition to the main variant, a second variant was drawn out, with standard IS running gear. An SPG version was drawn as well, although only with very superficial details.

The IS-style turret was mounted at the rear of the hull, which allowed for very little gun overhang, decreasing the chance of the gun getting damaged in tight places such as forests and cities, or steep maneuvers, such as trenchcrossing. Despite its general shape being similar to the turret of the IS, several key components had been done away with, such as the big commander cupola or air vent.

Original drawing of the IS-M from an old magazine. The caption said “Breakthrough tank IS-M”. Note the SPG in the background, explained below.
Source: Warspot

Powerplant

The engine was to be an M-40 aviation engine, equipped with 4 TK-88 turbochargers. The displacement was of 61.07 l and had an output of 1,200 hp. Other sources claim it was a modified variant of the standard V-2-IS, such as the V-11 or V-16, yet these would only output between 500 and 700 hp, far less than the 800 to 1,000 hp specified. The M-40 engine was based on an aviation engine, thus could run on both diesel and kerosene. Whatever the engine was, it had a 10 h running time. The powerplant was kept inside an own compartment in the center of the hull, protecting the fighting compartiment and ammunition, consequently isolating the driver. Fuel tank was in the front, to the right of the driver. As the sprocket remained to the rear of the hull, the entire braking and final drive ensemble was kept at the rear, as on the original IS. However, this meant that the gearbox and driveshaft ran through the floor of the crew compartment. The transmission was likely offered in 2 variations, electromechanical, very similar to that on the Ferdinand/Elefant, or a conventional mechanical one. The gearbox was of planetary type.

For access to these components, the rear engine plate could be opened and rested on the hinges, for access to the final drive and brakes. The roof of the engine compartment was also removable, and had one engine access hatch, 4 air vents and 4 air purification filters.

Suspension

Two different running gear options were presented, one with 6 large-diameter road wheels, which allowed the returning track to rest on them, or 6 IS road wheels with 3 return rollers. The large road wheels would offer improved mobility over very muddy terrain, where smaller road wheels would clog up with mud. Additionally, they removed the need for return rollers. In turn, the standard IS wheel layout was already in use on various IS and KV series of tanks, resulting in a cheaper and smarter logistic choice. In both variations, the wheels were sprung by torsion bars.

Crew

The crew was larger than on the IS-2, with 5 men; a commander, gunner, loader, driver, and radio operator. The commander sat in the left corner of the turret. He had a low profile cupola equipped with 2 opposite facing periscopes for vision. Sat in front of him was the gunner, who operated the main gun. He had the main gun sight for vision and an extra, fully rotating periscope for a better field of view. Opposite him, to the right of the gun, sat the loader. He had to load the 2-part ammunition gun, as well as assist the commander in various tasks. For entry and exit, he had his own hatch with a periscope. The driver sat in the front of the hull, from where he would control the tank with 2 tillers. One direct vision slit in the armor was provided, as well as a fully rotating periscope. For ease of driving during the night and visibility during maneuvers, the tank had a single headlamp on the right side of the upper hull. The radio operator was likely seated to the driver’s right, also in the hull. He also had a rotating periscope for vision.

Armament

The exact armament of the IS-M was never specified, other than its caliber, 122 mm. However, considering the German-style muzzle brake, it was a D-25T, as on the standard IS-2. The tank was equipped with 40 shells for the main gun.

122 mm D-25T ammunition specifications
Shell type	APHE (BR-471)	APHE (BR-471B)	HE (OF-471)
Mass (kg)	25	25	25
Muzzle velocity (m/s)	795	795	800
Explosive	160 g	160 g	3.6 kg TNT
Penetration	200 mm	207 mm	42 mm (calculated)

Around the tank, 3 GVG 7.62 mm machine guns were mounted, one coaxial to the main gun, one in a ball-mount at the rear of the turret, and one in the frontal hull, which is not visible in the drawings. A ‘large caliber’ machine gun was to be added to the commander’s cupola for anti-aircraft purposes, likely a DhSK 12.7 mm machine gun, but it is not shown in the drawings either.

The SPG variant of the IS-M was likely armed with an 152.4 mm BL-8 gun, developed at the beginning of 1944 and tested during July of the same year on the ISU-152-1 (Object 246).

152 mm BL-8 ammunition specifications
Shell type	APHE (BR-540)	APHE (BR-540B)	HE (OF-540)
Mass (kg)	48.8	48.96	43.56
Muzzle velocity (m/s)	850	850	850
Explosive	0.66 g	480 g	5.86 kg TNT
Penetration	247 mm	276 mm

ISU-152-1 (Object 246) armed with the 152 mm BL-8 gun.
Source: Wikimedia

Armor

The frontal plate was a continuous flat plate of 200 mm angled at around 45°. Side armor was 160 mm thick and angled at 60° on the upper hull and flat on the lower hull. The rear was also heavily angled and 120 mm thick. The turret was 160 mm all around, but being awkwardly rounded, it increased its effectiveness significantly frontally. This gave the IS-M superior protection to any heavy tank of the time, while still maintaining a modest 55 tonnes weight.

Frontal cutout view of the IS-M highlighting the hull armor and engine placement.
Source: Screenshot from original drawing

Variants

In the background of the original drawing, 2 additional vehicles can be seen. The first is also an IS-M, but with a different set of running gear, namely 6 IS-style road wheels and 3 smaller return rollers. This was likely added as an alternative to the large roadwheel design.

Full drawing of the IS-M variant with standard IS road wheels and return rollers.
Source: Screenshot from original drawing

Further back, a completely different vehicle is shown, a form of SPG based on the IS-M. The turret was replaced with a fixed casemate with a large 152 mm BL-8 gun. Interestingly, the running gear is the same as on the previously described IS-M.

View of the IS-M based SPG. Note the much larger muzzle brake, characteristic of the BL-8.
Source: Screenshot from original drawing

Return to Leningrad and Further Developments

The IS-M was short-lived. Alongside its 2 earlier counterparts, all were abandoned in April 1944. Instead, Factory No.100 began work on a vehicle meant to rival the SKB-2’s Object 701 and thus become the new generation heavy tank. It would incorporate several features from both the IS-M and the 2 wooden mock-ups presented on 18 April 1944. This was the IS-6, designed at first in secrecy. Like on the IS-M, 2 variants were designed, one with large diameter road wheels and a steeply armored hull (Object 252). The second would use an electromechanical transmission on an IS-2 lower hull (Object 253).

In May, with the Soviets having lifted the Siege of Leningrad, the SKB-2 design bureau and Factory No.100 were moved back, and thus the LKZ was revamped. Many engineers moved back, including Shashmurin. Back in Leningrad, they would continue work on the IS-6. In August 1944, the Object 244 was used as a testbed for the Object 252’s wheels, first designed on the IS-M, and later the 122 mm D-30 gun. The Object 244 itself was a prototype dating back to February 1944, meant to test the new 85 mm D-5T-85BM on an unmodified IS-1 (Object 237). The project was named IS-3, although this has nothing to do with the later IS-3 heavy tank (Object 703). After a military representative from Factory No.100 reported the IS-6 secret development to the GABTU, it was ordered that further development and prototype production should take place at Uralmashzavod in Yekaterinburg, but without the end game of entering production.

The modified Object 244 with 5 of the large-diameter road wheels and the 122 mm D-30 gun. Note the original IS road wheel in front of the sprocket.
Source: thedailybounce

Cutout drawings of the large-diameter roadwheel of the IS-6 (Object 252). They were originally designed for the IS-M.
Source: Warspot

The Object 252 IS-6 prototype during testing in November/December 1944. Despite being promising, its protection was deemed insufficient.
Source: Topwar

Back at ChKZ, which had been working full-time on the Object 701, it was realized that it needed to present its own modernization of the IS-2. Thus, in August 1944, they presented the blueprints of an upgrade to the IS-2. At first glance, it looked like an unchanged IS-2, but it featured various improvements, such as refined frontal armor layout, thicker turret armor, improved turret design, and many mechanical changes, such as improved cooling system and engine room. Allegedly, one prototype was built. Yet, by October 1944, the project was abandoned in favor of a new tank, which incorporated many IS-2 features, but was still radically new. It was called the Kirovets-1 and given the Object 703 index. After several alterations, most notably the addition of its most famous feature, the legendary pike-nose, the IS-3 was born.

The Kirovets-1 (not to be confused with the K-tanks), winter 1944.
Source: Warspot

The pike-nose on the IS-3 was ‘borrowed’ from the IS-2U and Object 252U, an upgrade of the IS-2 and Object 252 meant to equip them with pike-noses. As a matter of fact, the IS-2U, designed in November 1944, was the last genuine attempt to fundamentally upgrade the IS-2 heavy tank. The IS-2 U’s turret was itself heavily inspired by earlier designs, such as the IS-M.

The IS-2U designed at Factory No.100, was essentially an IS-2 with a new turret and frontal hull. It was the last significant attempt to modernize the IS-2.
Source: ofis7andthings

The IS-6 would end up unsatisfactory. The GABTU never intended to adopt it into service regardless. The Object 253 with the electromechanical transmission caught fire during testing. Both IS-6s were deemed insufficiently armored in comparison to the IS-4, and once the IS-3 was nearing production, the fate of the IS-6 was sealed.

Shashmurin himself, who had worked throughout the entire development of the IS-6, was never fond of the idea. Just like on the KV-13, he was a true believer in what he called “tank of maximum parameters” a tank which pushed the capabilities of the industry and designers to their limit, in an attempt to reach an unstoppable heavy tank. His first such vehicle was the IS-1 and later IS-2. For him, the IS-6 was a waste of time, especially considering the end of the war. As for the rivaling ChKZ heavy tanks, he had the following to say:

“We had finally created an almost perfect tank, capable of breaking through any enemy defenses. Ideal in its potential, all the qualities of the IS-2 could manifest themselves only in the development of the solutions found and tested in it. Alas, the improvement of the IS-2 was left to chance, and instead of developing already tested solutions, they began to invent new “bicycles”. An unjustified race began in the creation of independent models of heavy tanks, in many respects similar to the race that took place when creating the KV. The sad experience of the very recent past had taught us nothing…
The impressive, but unreliable IS-4 and IS-3 were being designed and created, another “monster” with two engines was being designed, a kind of electric locomotive was being built on tracks – a tank with an electromechanical transmission IS-6, which burned down after driving through the factory yard only 50 meters. In general, the design idea was in full swing, and in the meantime, the fighting was done by the “rude” workers of the IS-2, and not by the “handsome” IS-3, the production of which began in the early ‘45 and which immediately began to break down with the regularity of the sad memory of the KV-1.”

—N.F. Shashmurin, extract from Soviet Warrior magazine, interview by Sergey Ptichkin

After the war, Shashmurin would finally fulfill his dream of designing a true “tank of maximum parameters”, the IS-7, which indeed, pushed the technology of the time to its limits, being the heaviest Soviet tank ever built, as well as several work on ATGM-based heavy tanks, PT-76 and more.

Conclusion

The IS-M itself was a short-lived design meant to offer an arguably unnecessary upgrade to the IS-2. It would incorporate some very interesting features and solutions, such as a rear mounted turret, large diameter road wheels, and a curved hull. It alo took in consideration several running gear designs and an SPG layout. Nonetheless, despite its short life, it was a crucial factor in the developmental progress of Soviet heavy tanks during the Second World War, by leading directly into the development of the IS-6, which lost in turn to the more refined, though still crude, IS-3 and IS-4 designed at ChKZ. For Shashmurin, the IS-M was certainly not his most prideful creation, but through its odd nature, it complements well the career of one of the USSR’s most important heavy tank designers of the Second World War.

IS-M as illustrated by Pavel Alexe, funded by our Patreon campaign.

IS-M variant with standard IS road wheels and return rollers as illustrated by Pavel Alexe, funded by our Patreon campaign.

IS-M based SPG as illustrated by Pavel Alexe, funded by our Patreon campaign.

IS-M specifications
Dimensions (L-W-H)	7 x 3.2 x 2.7 (m)/td>
Total Weight, Battle Ready	55 tonness
Crew	5
Propulsion	1,200 hp diesel (V12) M-40 with 4 turbochargers or 500-700 V series engines
Speed	40 km/h
Armament	122 mm D-25T 3x GVG machine guns 1 (?) DhSK machine gun
Armor	Turret: 160 mm (hull) front: 200 mm Sides: 160 mm Rear: 120 mm Roof and belly: 30 mm
Total Production	0, drawings only

Sources:

IS Tanks – Igor Zheltov, Alexander Sergeev, Ivan Pavlov, Mikhail Pavlov
Supertanki Stalina IS-7 – Maxim Kolomiets
Heavy Tank IS-4 – Maxim Kolomiets
Tank Power of the USSR – M. N. Svirin
Modest genius: who created the IS-2 tank, which became a symbol of Victory – Rossiyskaya Gazeta (rg.ru) – Sergey Ptichkin
Holes in the armor -Sergey Ptichkin, Sergey Zykov
Tank Archives: Modernization on Paper – Yuri Pasholok, Igor Zheltov, Kirill Kokhsarov
Tank Archives: Wrong Place, Wrong Time – Yuri Pasholok
IS-2: Struggle for the Assembly Line | Warspot.net – Yuri Pasholok
Not in the amplitude of the | Warspot.ru -Yuri Pasholok
Muzzle wedge for heavy tank | Yuriy Pasholok | Zen (dzen.ru) – Yuri Pasholok
Tank Archives: Improving the IS-2 – Peter Samsonov
“>Russian Heavy Tank Object 244 – The Original IS-3 (thedailybounce.net) -Harkonnen
IS-2Sh – unusual “Stalin” (voentex.ru)

WW2 Soviet KV-4

KV-4 (Object 224) K.T.T.

KV-4 by the Kuzmin, Tarotko and Tarapatin. Illustrated by Pavel Alexe.

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

The KV-4 program started in March of 1941 at LKZ (Leningrad Kirov Factory), after rumors of the development of German heavy tanks. Instead of undergoing a conventional design path, J. Y. Kotin, head of the project, suggested a competition between engineers and the best entries to receive rewards. Second place was originally given to a trio of engineers, but the entry was later disqualified as it lacked a turret.

As the designs never received individual designations, aside from the general KV-4 and 224 (Object 224), most KV-4 designs are differentiated by adding the designers’ name(s). In this case, Kuzmin, Tarotko, and Tarapatin (KTT). A common name to refer to this design is K.T.T.S., which adds the Russian word “самоходка” (samokhodka) meaning self-propelled gun. This is misleading, however, as this was a heavy tank, not a self-propelled gun.

Development

–Dear reader: A more detailed development analysis of the KV-4 program can be found in the KV-4 Dukhov article–

KV-4 designs

Placement	Name	Mass (t)	Dimensions (m) (LxWxH)	Armament	Crew	Top speed (theoretical)	Armor	Reward /Rubles
1	Dukhov KV-4	82.5	8.150 3.790 3.153	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DT machine guns	6	40 km/h	Front top plate: 135 mm Front bottom plate: 130 mm Side plate: 125 mm Top and belly: 40 mm	5000
2	Kuzmin, Tarotko, Tarapatin KV-4	88	9.26 3.78 3.175	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DS-39 machine guns	6	36 km/h	Front: 125 mm Side: 125-100 mm Top and belly: 40 mm	3000
3	Tseits KV-4	90	8.85 4.03 3.62	107 mm ZiS-6 2x 7.62 mm DS-39 machine guns Unspecified flamethrower	7	45 km/h	Front hul upper plate: 50 mm Front hull bottom plate: 125 mm Turret:130 mm Side plate: 125 mm Top and belly: 50 mm	2800
4	Sychev KV-4	95 – 100	9.23 4.00 3.40	107 mm ZiS-6 (F-42) 45 mm 20-K 2x 7.62 mm DT machine guns	6	40 – 45	Turret: 135-125 mm Hull: 105 mm Top and belly: 40 mm	2000
4	Ermolaev KV-4	90	8.22 4.00 3.25	107 mm ZiS-6	6	35	130 mm
4	Ermolaev KV-4	95	8.52 4.00 3.25	107 mm ZiS-6 45 mm 20-K	6	35	130 mm	2000
5	Shashmurin KV-4	92	9.50 4.00 3.85	107 mm ZiS-6 (F-42) main cannon (112 or 102 rounds) 76 mm F-11 secondary cannon (120 rounds) 2x 7.62 mm DT machine guns (400 rounds) Unspecified flamethrower (hull)	7	35 km/h	Front top plate: 125 mm Side plate: 125 mm Top and belly: 50 to 40 mm	1500
6	Buganov KV-4	93	7.70 3.80 3.90	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front 125 mm	1000
6	Moskvin KV-4	101	9.573 4.03 3.74	107 mm ZiS-6 45 mm 20-K	6	40 km/h	Front 130 mm	1000
7	Pereverzev KV-4	100	9.5 3.8 3.82	107 mm ZiS-6 45 mm 20-K 2x 7.62 mm DT machine guns	6	39 km/h	Front: 125 mm	500
7	Bykov KV-4	98.6	9.5 4.03 3.65	107 mm ZiS-6 45 mm 20-K 7.62 mm DS-39 machine gun	8	36 km/h	Front 130 mm	500
7	Kalivod KV-4							500
N/A	Fedorenko KV-4	98.65	8.10 4.03 3.70	107 mm ZiS-6 45 mm M.1938 3x 7.62 mm DT machine guns Unspecified flamethrower	6	35 km/h	Front upper plate: 140 mm Side plate: 125 mm Turret: 125 mm Top and belly: 50 to 40 mm
N/A	Kreslavsky KV-4	92.6	9 4 3.225	107 mm ZiS-6 45 mm Mod.1937 20-K coaxial 3x 7.62 mm DT machine guns	6	45 km/h	Turret: 130 mm Front hull plate: 130 mm Front upper plate: 80 mm Side plate: 125 mm Rear plate: 130 mm Top /bottom: 50 -40 mm
N/A	Kruchenykh KV-4	107.7	9.13 4.03 3.78	107 mm ZiS-6 45 mm 20-K 4x 7.62 mm DT machine guns	9	30 km/h	Front: 130 mm
N/A	Mikhailov KV-4	86.5	9 3.6 3	107 mm ZiS-6 (F-42) 45 mm Mod.1937 20-K (hull-mounted) 3x 7.62 mm DT machine guns	6	50 km/h	Turret: 130 mm Hull: 130 mm Belly and belly: 50 – 40 mm
N/A	Marishkin KV-4	86.4	8.7 3.6 3.5	107 mm ZiS-6 45 mm 20-K	7	40 km/h	Front: 130 mm Upper frontal: 80 mm
N/A	Pavlov & Grigorev KV-4	91	8.5 4.0 3.6	107 mm ZiS-6 45 mm 20-K	6	45 km/h	Front: 100 – 125 mm
N/A	Turchaninov KV-4	89.5	9.8 4.0 3.0	107 mm ZiS-6 45 mm 20-K DT machine gun	7	35 km/h	Front: 125 mm
N/A	Strukov KV-4	92	8.6 4.0 3.8	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front: 80 – 130 mm
N/A	Unknown KV-4
N/A	Unknown KV-4

Soviet intelligence services sent a report to the Main Directorate of Armored Forces (GABTU) on 11 March 1941, concerning the development of German tanks. Most noteworthy, or perhaps alarming, was the development of a 90 tonne heavy tank, armed with a 105 mm gun. With hindsight, we can say that these were some early plans of the Pz.Kpfw.VII or Löwe.

Soviet military officials immediately realized their lack of preparation in this regard. The only genuine heavy tank in service during the spring of 1941 was the KV-1. While it was good on paper, it had been rushed into service for propaganda purposes, more than as a direct combat weapon. Just a few months later, these critical shortcomings would come to haunt not just its LKZ designers, but the Soviet Army altogether, showing how unreliable, slow, and heavy the tank was. The KV-1, even on its best day, would not be enough in an all-out war. Thus, as early as 1940, work on heavier tanks commenced at LKZ, in the form of the T-150, the T-220, and later the KV-3. These were fine vehicles on paper, with guns and armor far superior to even the much later Tiger I, but they were very unreliable, i.e. the KV-220 broke 2 engines during its trials and weighed 62.7 tonnes.

A T-150 towing the KV-220 during trials.
Source: ofis-7andotherthings

Just 10 days after the initial report, on 21 March 1941, the GABTU sent the requirements for the development of the KV-4, designated Object 224 to LKZ, tasked with designing the vehicle, where it would be simply called “224”. The military required it to be a 70 to 72 tonne heavy tank, armed with the 107 mm ZiS-6 in the turret, as well as a secondary 45 mm 20-K and at least 3 DT machine guns. Armor was to be of 130 mm at the front and 120 mm towards the sides and rear. Propulsion was provided by a 1,200 hp M-40 engine, also developed at LKZ. Crew was to be of 6 men. The deadline for the blueprints was 17 July, after which they were to be sent to various factories responsible for component production, namely Plant No.92 for construction of armaments in September and to Izhora plant in October, in charge of hull and turret production.

At LKZ, specifically the SKB-2 design bureau, work had not even started when the GABTU changed their minds and altered the KV-4 requirements on 7 April, as well as those of the KV-3, which was now to be improved and act as a stopgap until the heavier KVs were made. Most surprisingly was the introduction of a new tank, even larger and heavier than the KV-4, the KV-5, with a mass of at least 90 tonnes and 170 mm of frontal armor. The KV-4 itself was also improved, its weight increased to 75 tonnes, frontal armor to 135 mm and side/rear to 125 mm.

Work on the KV-4 began on 10 April, with J. Y. Kotint as the head of the project. Due to the very loose requirements and ability to start from scratch, he decided to test his engineer’s creativity. Thus, with the approval of the factory director I.M. Zaltsman, he set up a competition for the KV-4’s designs. Engineers would brainstorm what the KV-4 would look like, encouraging original and innovative features.The top few designs would get a financial reward. Over 20 engineers competed, submitting over 20 individual designs. The winning design was that of N. L. Dukhov, which was essentially an enlarged KV-220, but with a peculiar semi-automatic loading system. Second place went to the trio of K. I. Kuzmin, V. I Tarotko, and P. S. Tarapatin, who designed a very unorthodox tank, resembling nothing seen before, with the gun mounted in a central rotating sponson, with a smaller turret on top, in a more ‘symmetric’ fashion compared to the American M3 Lee tank. Third place went to N.V. Tseits, with a more conventional design, but which sought to have as low a hull as possible, with a large cylindrical turret. Several other designers also received monetary compensation for their designs.

The Designers

This design was created by 3 different engineers working together, K. I. Kuzmin, V. I. Tarotko, and P. S. Tarapatin.

K.I. Kuzmin began his work at the Krasny Putilovets tractor plant, and would begin work at SKB-2 on the T-28. He would go on to work on most of SKB-2s tank projects, including the T-29, SMK, KV-1 also worked alongside L.E. Sychev on the PPG (Object 217). Furthermore, he worked on the KV-3, KV-4 and was design group leader on the KV-5 and was the hull designer of the KV-13.

V.I. Tarotko’s first project at SKB-2 was on the SMK, and later worked the KV-1 as part of a trainee team of young design engineers. After the start of the war, he began work on SPGs, including the SU-122 and SU-152. In late 1944, alongside G.N. Moskvin, V.I. Tarotko would develop the “pike-nose” armor layout for the Object 252U and IS-2U, becoming an iconic design feature on Soviet post-war heavy tanks. Afterwards he would work on the development of the IS-3 and IS-4. Worthy to note is that some documents mention S.V. Mickiewicz instead of V.I. Tarotko, though likely a mistake.

V.I. Tarotko
Source: Constructors of combat vehicles

Similarly to Tarotko, P.S. Tarapatin was also a young engineers, having just finished his studies. His career began working on developing the KV-1, but after the start of the war, he would work alongside his colleague Tarotko on the SU-122 and SU-152.

Design

The general layout of the KV-4 as proposed by the K.T.T. trio is one of the most unorthodox and unique amongst all other proposals. The driver and bow machine gunner sat in the hull, as on most other KV tanks. Yet right behind them was the engine and gearbox compartment, without any firewall or separation. Behind the powerpack was the fighting compartment, separated by a firewall. The main 107 mm ZiS-6 gun was mounted in a large, rotating sponson which could traverse 60° to both the left and right. Behind it, on the roof of the fighting compartment was a fully rotating turret, armed with a 45 mm 20-K gun. Right behind the fighting compartiment, separated by a partially curved firewall, was the air cooling system, which would both evacuate and intake air for the engine. While not ideal, there was simply no room to locate it closer to the engine. Thanks to the well integrated gun and low roof, the vehicle could have been relatively easy to transport (setting aside its weight) and presented a low profile, was it not for the small turret which placed it amongst the taller KV-4 designs, at 3.78 m. The engine was a M-40 V-12 aircraft engine, equipped with 4x TK-88 turbochargers, despite being a diesel engine. It had an output of 1,200 hp, and was connected to the gearbox which ran through the hull, in between the driver and bow machine gunner. Thus, the tank had frontal drive sprockets. It was estimated to reach a top speed of 36 km/h.

Due to its “turretless” layout, the tank is sometimes mistaken for a self-propelled gun, most notably, by Wargaming’s videogame World of Tanks. This is simply not the case. Similarly, N.F. Shashmurin had also opted to mount the main gun of his tank inside the hull, and after being forced (otherwise it would have been disqualified), he added a KV-1 turret on top. Truth is that there were plans on 18 April to design a KV-4 based SPG, but with just 60 mm of casemate armor and an improved 107 mm gun. The design by the K.T.T. trio is simply a heavy tank with the main gun mounted in the hull, albeit with a significant gun arc.

Side profile of the trio’s KV-4 proposal. The engine is situated between the driver and the fighting compartiment.
Source: ASKM

Crew

The crew was to be of 6 men, commander, gunner, 2 loaders, bow machine gunner, and driver. The gunner and one of the loaders sat within the fighting compartiment in the hull and manned the 107 mm ZiS-6 gun. The main gun shells were stowed on the floor of the tank and in racks to the rear of the compartiment. The tank’s commander and a second loader were in the turret. Here, the commander could scan the battlefield with the rotating turret, offering an excellent view, while also being able to independently engage targets. The second loader was also in the turret, but had to bend down from his seat to lift the light, 1.43 kg, 45 mm shells into the breech. Down into the hull, at the front, was the driver (left) and bow machine gunner (right), likely also tasked with operating the radio. Both had ball-mounted DS-39 7.62 mm machine guns at their disposal, for suppressive fire more than anything. Though lack of any other machine guns, especially one with an extended firing arc, in a “mostly” turretless vehicle is a major downside, especially as many other KV-4 designs had several turrets capable of rotating independently of each other.

Top down view of the KV-4 proposal where the 2 7.62 mm DS-39 bow machine guns can be seen.
Source: ASKM

Armor

Compared to other KV-4 designs, the tank in question’s armor was on the thinner side, with “just” 125 mm thick plates at the front, sides and rear. Top and belly plates were 40 mm thick. Curiously, despite being very similar to the T-50 or T-50-2 turret, the top turret was just as well armored, with what appears to be 125 mm thick plates all around, aside for the area around the gun mantlet and roof, which were 40 mm thick.

Armament

The main gun was the 107 mm ZiS-6, designed by V. G. Grabin in 45 days, at the request of Stalin himself for the new heavy tanks, although experiments and testing of similar guns started long before, in 1940. The shells weighed 18.8 kg and had a muzzle velocity of 800 to 840 m/s. Some sources claim it could penetrate 115 m of armor from 1,000 m.

The gun was mounted in a semi-rotating sponson. In other words, it was fixed on a rotating armored housing, where it could traverse 60° in both directions. Additionally, the gun had vertical movement of -5°. However, the elevation is unknown, as the document is damaged where the value is written. The crew would be required to move along with the gun, unless the gunner was attached to it, like in a conventional turret.

Regarding secondary armament, the tank had a single 45 mm 20-K Mod. 1938 gun, mounted in a smaller turret. It had 360° horizontal traverse and vertical elevation of +20°/-5°. This gun fired 1.43 kg shells with a velocity of 760 m/s. While this gun might seem underwhelming, in tandem with the 107 mm ZiS-6, it was more than useful. It was still the main gun in use on several Soviet tanks in service, from the BT-5, BT-7 and T-26, to the new T-50 and massive T-35. With hindsight, it is clear that this gun would quickly become obsolete, especially as a main weapon.

The KV-2 with the ZiS-6 107 mm gun and KV-3 mantlet during testing, June 1941.
Source: Thinky via WT forums

The tank only featured 2 DS-39 7.62 mm machine guns, both in fixed ball mounts in the hull, for the driver and bow gunner/radio operator. This opened large fire blindspots for the semi-turretless tank, increasing the dependence on the 45 mm gun, and in turn, strain on the commander, who acted as its gunner. Even so, the lack of any other machine gun meant that suppressive fire was impossible and the tank was vulnerable to rear infantry attacks.

Misinterpretation

The 3 engineers sought to create an eccentric vehicle, with several unique features, such as the sponson-mounted main gun or engine cooling layout. For these, Kotin and the judges initially awarded the design second place, landing the 3 men 3000 Rubles to share. However their joy was short-lived, as their design was later disqualified after concerns that it did not fit the GABTU’s requirements, which originally specified that the main gun was to be mounted in a fully-rotating turret. This detail was (likely) omitted in the second request. The result of their disqualification meant that the design by N.V. Tseits would be lifted to second place, which had a direct impact on the development of the KV-5, which used many aspects of Tseits’ KV-4 proposal. Oddly, Shashmurin’s design, which also mounted the main gun in a casemate, was not disqualified. Furthermore, he used the “wrong” gun, placing a KV-1 turret and gun on the roof of the casemate.

The KV-4 proposal as it is represented in the game World of Tanks, called KTTS. Note that it does not have the original 107 mm ZiS-6, but rather it has the 107 mm M-75, a gun which the KV-4 heavy tank was never intended to equip.
Source: Wargaming

The entire KV-4 project was rather hopeless. After the announcement in May of the competition’s winner, N.L. Dukhov, work on the KV-4 virtually stopped. Instead, the team shifted focus towards preparing blueprints for the KV-5. Work on these heavy tanks was slowed down by the German invasion of the USSR on 22 June, and eventually, completely halted in September, when German troops were approaching Leningrad and the SKB-2’s design bureau was evacuated to ChTZ, later renamed ChKZ, in Chelyabinsk.

The KV-4 as designed by Kuzmin, Tarotko, and Tarapatin (KTT). Illustration by Pavel Alexe.

Sources:Breakthrough tank KV – Maxim Kolomiets
Supertanki Stalina IS-7 – Maxim Kolomiets
KV 163 1939-1941 – Maxim Kolomiets
KV heavy tank – compiled by E.V. Egers
Confrontation – Ibragimov Danyial Sabirovich
Bronevoy Schit Stalina. Istoriya Sovetskogo Tanka (1937-1943) M. Svirin
About the forgotten creators of Soviet armored power. (historyntagil.ru) – S.I. Pudovkin
German Lion | Warspot.ru – Yuri Pasholok
Tank building on the verge of common sense | Warspot.ru – Yuri Pasholok
Large caliber for large HF | Yuriy Pasholok | Yandex Zen – Yuri Pasholok
Tank Archives: Soviet 107 mm Guns – Peter Samsonov
Tank Archives: KV-3 Mulligan – Peter Samsonov
Tank Archives: Heavy Tank Costs – Peter Samsonov
Tank Archives: ZIS-6 Characteristics – Peter Samsonov
Tank Archives: Modernization on Paper
Опытный танк с боевой биографией | Warspot.ru
Тарапатин П.С. (famhist.ru)
Танкостроение на грани здравого смысла | Warspot.ru
Soviet heavy tanks series kv. History of creation External fuel tanks tank KV 1 (ezoteriker.ru)
About the forgotten creators of Soviet armored power. (historyntagil.ru)
Revolution Dingxin (1) – I love to look at the bib (wakwb.com)
Soviet heavy tanks 45-65 – 0020.htm (narod2.ru)

KV-4 K.T.T. specifications
Dimensions (L-W-H)	9.26 – 3.175 – 3.78 m
Total Weight, Battle Ready	88 tonnes
Crew	6 (Commander, Gunner, Driver, Radio operator, loader, turret mechanic/loader assistant)
Propulsion	1,200 hp diesel/kerosene V-12 M-40 with 4 turbochargers
Speed	36 km/h (hypothetical)
Suspension	Torsion bar, 7 wheels per side
Armament	107 mm ZiS-6 (F-42) 45 mm 20-K 2x 7.62 mm DS-39 machine guns
Armor	Front: 125 mm Side: 125 mm Rear: 125 mm Top and belly: 40 mm
Total Production	0, blueprints only

WW2 Soviet KV-4

KV-4 (Object 224) Kresavsky

Post author By Pavel Alexe
Post date September 28, 2022
2 Comments on KV-4 (Object 224) Kresavsky

Interpretation of Kreslavsky's KV-4 design by Pavel Alexe. Illustration funded through our Patreon campaign.

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

The KV-4 program can be regarded as one of the most unsuccessful and short-lived tank design ideas of the Soviet Union during the WW2 period. This is especially true considering its expectations, the caliber of the engineers behind it, J. Y. Kotin and N. L. Dukhov, to name a few, and those who ordered it to begin with, including Stalin himself. Many designs were proposed in what was essentially a drawing competition, some quite sensible, while some were less so. One rather forgettable design was that by young engineer M. I. Kresavsky, who did not receive any awards for his design. Big, heavy, and with no advantages over other designs, it remained, and still is largely, forgotten, with just minor recognition in Wargaming’s World of Tanks.

Development

–Dear reader: A more detailed development analysis of the KV-4 program can be found in the KV-4 Dukhov article–

KV-4 designs

Placement	Name	Mass (t)	Dimensions (m) (LxWxH)	Armament	Crew	Top speed (theoretical)	Armor	Reward /Rubles
1	Dukhov KV-4	82.5	8.150 3.790 3.153	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DT machine guns	6	40 km/h	Front top plate: 135 mm Front bottom plate: 130 mm Side plate: 125 mm Top and belly: 40 mm	5000
2	Kuzmin, Tarotko, Tarapatin KV-4	88	9.26 3.78 3.175	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DS-39 machine guns	6	36 km/h	Front: 125 mm Side: 125-100 mm Top and belly: 40 mm	3000
3	Tseits KV-4	90	8.85 4.03 3.62	107 mm ZiS-6 2x 7.62 mm DS-39 machine guns Unspecified flamethrower	7	45 km/h	Front hul upper plate: 50 mm Front hull bottom plate: 125 mm Turret:130 mm Side plate: 125 mm Top and belly: 50 mm	2800
4	Sychev KV-4	95 – 100	9.23 4.00 3.40	107 mm ZiS-6 (F-42) 45 mm 20-K 2x 7.62 mm DT machine guns	6	40 – 45	Turret: 135-125 mm Hull: 105 mm Top and belly: 40 mm	2000
4	Ermolaev KV-4	90	8.22 4.00 3.25	107 mm ZiS-6	6	35	130 mm
4	Ermolaev KV-4	95	8.52 4.00 3.25	107 mm ZiS-6 45 mm 20-K	6	35	130 mm	2000
5	Shashmurin KV-4	92	9.50 4.00 3.85	107 mm ZiS-6 (F-42) main cannon (112 or 102 rounds) 76 mm F-11 secondary cannon (120 rounds) 2x 7.62 mm DT machine guns (400 rounds) Unspecified flamethrower (hull)	7	35 km/h	Front top plate: 125 mm Side plate: 125 mm Top and belly: 50 to 40 mm	1500
6	Buganov KV-4	93	7.70 3.80 3.90	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front 125 mm	1000
6	Moskvin KV-4	101	9.573 4.03 3.74	107 mm ZiS-6 45 mm 20-K	6	40 km/h	Front 130 mm	1000
7	Pereverzev KV-4	100	9.5 3.8 3.82	107 mm ZiS-6 45 mm 20-K 2x 7.62 mm DT machine guns	6	39 km/h	Front: 125 mm	500
7	Bykov KV-4	98.6	9.5 4.03 3.65	107 mm ZiS-6 45 mm 20-K 7.62 mm DS-39 machine gun	8	36 km/h	Front 130 mm	500
7	Kalivod KV-4							500
N/A	Fedorenko KV-4	98.65	8.10 4.03 3.70	107 mm ZiS-6 45 mm M.1938 3x 7.62 mm DT machine guns Unspecified flamethrower	6	35 km/h	Front upper plate: 140 mm Side plate: 125 mm Turret: 125 mm Top and belly: 50 to 40 mm
N/A	Kreslavsky KV-4	92.6	9 4 3.225	107 mm ZiS-6 45 mm Mod.1937 20-K coaxial 3x 7.62 mm DT machine guns	6	45 km/h	Turret: 130 mm Front hull plate: 130 mm Front upper plate: 80 mm Side plate: 125 mm Rear plate: 130 mm Top /bottom: 50 -40 mm
N/A	Kruchenykh KV-4	107.7	9.13 4.03 3.78	107 mm ZiS-6 45 mm 20-K 4x 7.62 mm DT machine guns	9	30 km/h	Front: 130 mm
N/A	Mikhailov KV-4	86.5	9 3.6 3	107 mm ZiS-6 (F-42) 45 mm Mod.1937 20-K (hull-mounted) 3x 7.62 mm DT machine guns	6	50 km/h	Turret: 130 mm Hull: 130 mm Belly and belly: 50 – 40 mm
N/A	Marishkin KV-4	86.4	8.7 3.6 3.5	107 mm ZiS-6 45 mm 20-K	7	40 km/h	Front: 130 mm Upper frontal: 80 mm
N/A	Pavlov & Grigorev KV-4	91	8.5 4.0 3.6	107 mm ZiS-6 45 mm 20-K	6	45 km/h	Front: 100 – 125 mm
N/A	Turchaninov KV-4	89.5	9.8 4.0 3.0	107 mm ZiS-6 45 mm 20-K DT machine gun	7	35 km/h	Front: 125 mm
N/A	Strukov KV-4	92	8.6 4.0 3.8	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front: 80 – 130 mm
N/A	Unknown KV-4
N/A	Unknown KV-4

Despite the Molotov-Ribbentrop Pact, and previous German-Soviet tank collaborations, in 1941, the situation in Europe was ugly, and German expansion was worrying for the Soviets. Things took a turn for the worse when, on 11 March, a report submitted by the Soviet Intelligence agencies regarding German armament development included a chapter on German heavy tanks. Here, amongst other tanks, a 90-tonne heavy tank armed with a 105 mm gun was mentioned. The Soviet military, recognising its unpreparedness against such a threat, ordered work on a Soviet tank that could match such an enemy tank.

Just 10 days after the initial report was sent, on 21 March, the GABTU (Main Directorate of Armed Forces) sent out the request for a new heavy tank, designated Object 224 or KV-4, as it was to be designed at the Leningrad Kirov plant (LKZ). The design of the tank was to be done by the SKB-2 design bureau, headed by the famous tank designer J. Y. Kotin. The Soviet state requested the tank to be a 70-72 tonne tank and armed with the 107 mm ZiS-6 main gun, a secondary 20-K 45 mm gun, 3 machine guns, and 1 flamethrower. Armor was to be of 130 mm at the front and 120 mm towards the sides and rear. Propulsion was to be provided by an M-40 aviation diesel engine, with 4 TK-88 turbochargers, outputting 1,200 hp. The crew was to be of 6. Deadline for the tank plans was 17 July.

It was not long until the GABTU changed their minds and, on 7 April, reordered the entire program. Firstly, the KV-3, which was previously under development, was reinstated and upgraded to act as a stopgap tank until the KV-4 and KV-5 were ready for production. The KV-5 itself was created, a 90-tonne tank which would have had 170 mm of armor at the front and 150 mm at the sides, though same armament and powerpack as the KV-4. The 2 would compete against each other, and the winning vehicle would be produced. The specifications of the KV-4 were also tampered with, increasing the weight to at least 75 tonnes, 135 mm of frontal armor and 125 mm on the sides and rear. The deadline for the tank’s drawings was narrowed to 15 June.

Work began on 10 April at LKZ, and Kotin, after seeking approval and funding from factory director I. M. Zaltsman, decided to let the engineers compete against each other. The best designs would be financially rewarded. The SKB-2 design bureau already had experience with heavy tank development. It was the same group of people behind the SMK, T-100, KV-1, T-150, KV-220, and KV-3. Over 20 engineers from SKB-2 competed against each other, some even teaming up, presenting well over 20 different tank designs. The winner was N. L. Dukhov, with a KV-4 that was essentially just an enlarged KV-220. Second place went to the trio of K. I. Kuzmin, V. I Tarotko and P. S. Tarapatin, which had the main gun inside the turret (and later got disqualified), and third place to N. V. Tseits, whose design featured a very low profile hull, but a massive turret. Though not all designs were as well received. Over 10 designs did not receive any rewards. One of these was the one by engineer M. I. Kresavsky.

M.I. Kresavsky

A young engineer from the Leningrad Politechnic institute, M.I. Kresavsky (also sometimes spelled Kreslavsky) was drafted by Kotin and worked for him for 30 years. Apart from his work on the KV-4, Kresavsky worked on the SMK and the transmission of the KV-1, alongside V. A. Kozlovsky. He also participated in the design of the KV-2 IS and IS-3 tanks.

A young M.I. Kresavsky at SKB-2.
Source: Constructor of Combat vehicles- N.Popov

Design

At first glance, the KV-4, as designed by Kresavsky, was nothing special, other than its sheer size. At exactly 9 m in length, and over 4 m in width, it landed on the larger side of the KV-4 spectrum. Mass-wise, the 92.6 tonne design was around average, with the lightest design being 82.5 tonnes and the heaviest 107.7 tonnes. Yet, a couple of details make it into a rather strange design from a mechanical aspect. Primarily, the engine was mounted over the 3rd and 4th roadwheels, right behind the driver, separated by a firewall. The transmission protruded through the firewall towards the final drive, located at the driver’s feet. This, in turn, worked the front drive sprockets. In terms of propulsion, the tank was, as requested by the GABTU, equipped with an 1,200 hp M-40 engine, with 4 TK-88 turbochargers. For vision, the driver had a complex, rounded armored bulge, extending from the hull, made from several cast and welded components. The bow machine gunner had his own such “bulge” on the opposite side of the hull.

The turret and fighting compartment were behind the engine room, separated by another firewall. Inside the hull, ammunition was stowed. Above was the hexagonal turret, made from 125 to 130 mm plates pressed into shape and welded together. On top, a conical turret with several vision slits was attached. The main 107 mm ZiS-6 gun was mounted to the left of the center, while the 45 mm 20-K to the right. Back inside the hull, a 4th compartment was added, which housed the fuel tanks and engine cooling system, which was pulled through the fighting compartment. While seemingly complex, this entire layout offered several advantages. Firstly, it protected the crew, ammunition, and fuel tanks from frontal impacts. Secondly, the turret was offset far enough to the rear that the gun barely hung over the hull, easing transport and reducing potential barrel damage during maneuvers in areas such as cities or forests.

Cutout side view of Kreslavsky’s design.
Source: ASKM

Crew

The vehicle had a crew of 6: commander, gunner, 2 loaders, driver, and bow machine gunner/radio operator. The commander, seated in the back of the turret, operated the cupola, equipped with 6 vision slits and one 7.62 mm DT machine gun. The gunner sat to the right of the 107 mm main gun and was very likely able to remotely operate the 45 mm gun too. The 2 guns had individual loaders sat behind them. Another ball-mounted DT machine gun was mounted on the rear plate of the turret, likely to be used by one of the loaders. There are no visible entry/exit hatches, but a reasonable assumption would conclude that there would be 2 hatches, one on the cupola and another on the left side of the turret roof.

The driver and bow gunner were seated in the hull, each on either side of the gearbox. Both had their own armored, rounded protrusions, which allowed for more headroom and better visibility, equipped with at least 4 vision slits each.

Top view drawing of Kreslavsky’s KV-4. The tracks are missing from this scheme. Note the gun mantlet and the way the guns are placed.
Source: AKSM

Armor

In relation to other KV-4 designs, the armor on Kreslavsky’s KV-4 was nothing special. Frontal plates on both the hull and turret were 130 mm thick and rounded, increasing the effectiveness from certain angles. Only the frontal upper plate was thinner, at just 80 mm, though it was angled at 10° from horizontal, bringing it to an LoS thickness of 461 mm. Armor on the driver’s cupola varied from 125 mm at the front to 60 mm on the roof. Side and rear armor was 125 mm thick, while roof armor was 50 mm and belly armor was 40 mm thick.

Armament

The main gun on all KV-4 designs was the ZiS-6, with a 107 mm caliber, designed by the famous V. A. Grabin. By March 1941, the Soviets had already worked for several months on 107 mm caliber guns, and were proving to be very powerful, especially in regards to armor penetration. Thus, when the news of German heavy tanks came, Stalin himself rang Grabin, requesting the design of a new, powerful gun. Thus the F-42 was born, completed in just 45 days. In March, it was renamed to ZiS-6. Factory trials proved promising after delayed tests were conducted on a KV-2 armed with the gun and a KV-3 gun mantlet. Production started shortly after. However, according to Grabin’s memoirs, after the cancellation of the LKZ heavy tanks, over 800 such gun barrels had to be melted. The gun itself had an 18.8 kg one-piece shell, with a muzzle velocity between 800 to 840 m/s.

One of the first ZiS-6 107 mm guns produced.
Source: Yuri Pasholok via Warspot

The secondary armament, a 20-K 45 mm, was mounted coaxially, to the right of the center of the mantlet. There was no space in between the 2 guns for another gunner, so it is assumed that the main and single gunner sat to the left of the main gun, and could remotely operate the 45 mm gun too, using some form of mechanical system. The gun itself fired BR-240SP AP rounds, which weighed 1.43 kg, had a muzzle velocity of 757 m/s and a (artificially calculated) penetration of 73 mm at 0 m.

A total of 3 DT 7.62 mm machine guns were mounted on ball mounts in the tank, one by the bow machine gunner, in the hull, one in the commander’s cupola and one on the rear turret plate, likely operated by one of the loaders, when necessary.

Drawings og the 45 mm K-20 gun with its turret gun mount.
Source: Armored Wiki via VK.com

Dinosaur Extinction

The KV-4 program did not go far at all. The LKZ staff failed to present final blueprints in time, and the program was delayed. Without them, the Izhora plant, tasked with production of the tank prototype, could not begin work either. The truth is that the program slowly died after the competition, and work shifted towards the more exciting KV-5. With the German invasion of the Soviet Union on 22 June 1941, work still continued. Only in August, when the German forces were approaching Leningrad, did work on these tanks pause. The SKB-2 design bureau was evacuated to the ChTZ, later renamed ChKZ in Chelyabinsk, and work on the KV-4 never resumed.

Conclusion

Though one might see the KV-4 program as unlucky and doomed, Kresavsky’s own proposal was even more so. It failed to spark any interest from the ‘judges’ and brought nothing revolutionary enough, in what was actually quite a large tank, even compared to other KV-4 designs. Only in the recent decade has Kreslavsky’s proposal received some ‘love’, being introduced in the massively multiplayer online game, World of Tanks.

KV-4 Kresavsky as interpreted by Wargaming. Note that it does not have the original 107 mm ZiS-6, but rather it has the 107 mm M-75, a gun that the KV-4 heavy tank was never intended to mount.
Source: TheDailyBounce.net

Interpretation of Kresavsky’s KV-4 design by Pavel Alexe. Illustration funded through our Patreon campaign.

KV-4 Kresavsky Specifications
Dimensions (L-W-H)	9.0 – 4.0 – 3.225 m
Total weight, battle-ready	92.6 tonnes
Crew	6 (commander, main gunner, driver, secondary gunner, radio operator, & loader )
Propulsion	1,200 hp diesel V-12 M-40 with 4 turbochargers
Speed	45 km/h
Suspension	Torsion bar, 7 wheels per side
Armament	107 mm ZiS-6 (F-42) (103 rounds) 45 mm Mod.1937 20-K coaxial (140 rounds) 3x 7.62 mm DT machine guns (4,000 rounds)
Armor	Turret: 130 mm Front hull plate: 130 mm Front upper plate: 80 mm Side plate: 125 mm Rear plate: 130 mm Top: 50 mm Bottom: 40 mm
No. Built	0, blueprints only

Sources

Breakthrough tank KV – Maxim Kolomiets
Supertanki Stalina IS-7 – Maxim Kolomiets
KV 163 1939-1941 – Maxim Kolomiets
Bronevoy Schit Stalina. Istoriya Sovetskogo Tanka (1937-1943) M. Svirin
Kreslavsky M.I. (famhist.ru)
Tank building on the verge of common sense | Warspot.ru – Yuri Pasholok
Tank Archives: Soviet 107 mm Guns – Peter Samsonov
Tank Archives: KV-3 Mulligan – Peter Samsonov
Tank Archives: ZIS-6 Characteristics – Peter Samsonov

WW2 Soviet KV-4

KV-4 (Object 224) Tseits

Interpretation of Tseits' KV-4 design by Pavel Alexe. Illustration funded through our Patreon campaign.

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

The KV-4 heavy tank program was started in April of 1941, based on an illusion of Soviet Intelligence services, which claimed that the Germans were working on a 90-tonne heavy tank. Design was undertaken at the LKZ factory via a competition of engineers. Amongst them was senior engineer N. V. Tseits, who designed one of the most successful KV-4 designs, being awarded third, and later, second place.

Development

–Dear reader: A more detailed development analysis of the KV-4 program can be found in the KV-4 Dukhov article–

KV-4 designs

Placement	Name	Mass (t)	Dimensions (m) (LxWxH)	Armament	Crew	Top speed (theoretical)	Armor	Reward /Rubles
1	Dukhov KV-4	82.5	8.150 3.790 3.153	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DT machine guns	6	40 km/h	Front top plate: 135 mm Front bottom plate: 130 mm Side plate: 125 mm Top and belly: 40 mm	5000
2	Kuzmin, Tarotko, Tarapatin KV-4	88	9.26 3.78 3.175	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DS-39 machine guns	6	36 km/h	Front: 125 mm Side: 125-100 mm Top and belly: 40 mm	3000
3	Tseits KV-4	90	8.85 4.03 3.62	107 mm ZiS-6 2x 7.62 mm DS-39 machine guns Unspecified flamethrower	7	45 km/h	Front hul upper plate: 50 mm Front hull bottom plate: 125 mm Turret:130 mm Side plate: 125 mm Top and belly: 50 mm	2800
4	Sychev KV-4	95 – 100	9.23 4.00 3.40	107 mm ZiS-6 (F-42) 45 mm 20-K 2x 7.62 mm DT machine guns	6	40 – 45	Turret: 135-125 mm Hull: 105 mm Top and belly: 40 mm	2000
4	Ermolaev KV-4	90	8.22 4.00 3.25	107 mm ZiS-6	6	35	130 mm
4	Ermolaev KV-4	95	8.52 4.00 3.25	107 mm ZiS-6 45 mm 20-K	6	35	130 mm	2000
5	Shashmurin KV-4	92	9.50 4.00 3.85	107 mm ZiS-6 (F-42) main cannon (112 or 102 rounds) 76 mm F-11 secondary cannon (120 rounds) 2x 7.62 mm DT machine guns (400 rounds) Unspecified flamethrower (hull)	7	35 km/h	Front top plate: 125 mm Side plate: 125 mm Top and belly: 50 to 40 mm	1500
6	Buganov KV-4	93	7.70 3.80 3.90	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front 125 mm	1000
6	Moskvin KV-4	101	9.573 4.03 3.74	107 mm ZiS-6 45 mm 20-K	6	40 km/h	Front 130 mm	1000
7	Pereverzev KV-4	100	9.5 3.8 3.82	107 mm ZiS-6 45 mm 20-K 2x 7.62 mm DT machine guns	6	39 km/h	Front: 125 mm	500
7	Bykov KV-4	98.6	9.5 4.03 3.65	107 mm ZiS-6 45 mm 20-K 7.62 mm DS-39 machine gun	8	36 km/h	Front 130 mm	500
7	Kalivod KV-4							500
N/A	Fedorenko KV-4	98.65	8.10 4.03 3.70	107 mm ZiS-6 45 mm M.1938 3x 7.62 mm DT machine guns Unspecified flamethrower	6	35 km/h	Front upper plate: 140 mm Side plate: 125 mm Turret: 125 mm Top and belly: 50 to 40 mm
N/A	Kreslavsky KV-4	92.6	9 4 3.225	107 mm ZiS-6 45 mm Mod.1937 20-K coaxial 3x 7.62 mm DT machine guns	6	45 km/h	Turret: 130 mm Front hull plate: 130 mm Front upper plate: 80 mm Side plate: 125 mm Rear plate: 130 mm Top /bottom: 50 -40 mm
N/A	Kruchenykh KV-4	107.7	9.13 4.03 3.78	107 mm ZiS-6 45 mm 20-K 4x 7.62 mm DT machine guns	9	30 km/h	Front: 130 mm
N/A	Mikhailov KV-4	86.5	9 3.6 3	107 mm ZiS-6 (F-42) 45 mm Mod.1937 20-K (hull-mounted) 3x 7.62 mm DT machine guns	6	50 km/h	Turret: 130 mm Hull: 130 mm Belly and belly: 50 – 40 mm
N/A	Marishkin KV-4	86.4	8.7 3.6 3.5	107 mm ZiS-6 45 mm 20-K	7	40 km/h	Front: 130 mm Upper frontal: 80 mm
N/A	Pavlov & Grigorev KV-4	91	8.5 4.0 3.6	107 mm ZiS-6 45 mm 20-K	6	45 km/h	Front: 100 – 125 mm
N/A	Turchaninov KV-4	89.5	9.8 4.0 3.0	107 mm ZiS-6 45 mm 20-K DT machine gun	7	35 km/h	Front: 125 mm
N/A	Strukov KV-4	92	8.6 4.0 3.8	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front: 80 – 130 mm
N/A	Unknown KV-4
N/A	Unknown KV-4

On 11 March 1941, the Soviet intelligence services sent a report to the Main Directorate of Armed Forces (GABTU) regarding German tank development. Amongst several other topics, heavy tanks had been discussed, of which a 90 tonne heavy tank armed with a 105 mm gun which was apparently under development.

This came as a large surprise to the Soviet military officials, which immediately realized their lack of preparation in this regard. At the time, the KV-1 was the main heavy tank of the Soviet armored forces, but it was completely unprepared for service, let alone combat. Its problems would become apparent at the start of the German invasion of the USSR, highlighting its poor mobility and mechanical unreliability. Work began as early as 1940 on creating a heavier and better armored KV-1, most notably the T-150, KV-220, and later the KV-3. Here, it is relevant to remember that even the KV-220, armored with a 85 mm gun, could have stood up to even the Tiger I, which entered service over a year later, had its crucial mechanical problems been fixed.

Shortly after, on 21 March 1941, the GABTU sent out the requirements for the development of the KV-4, designated Object 224, or just 224. It was to be a 70 to 72 tonne heavy tank, armed with the 107 mm ZiS-6 in the turret, as well as a secondary 45 mm 20-K and at least 3 DT machine guns. Armor was to be of 130 mm at the front and 120 mm towards the sides and rear. Propulsion was provided by a 1,200 hp M-40 engine, also developed at LKZ. Crew was to be of 6 men. On 27 March 1941, the deadline for the tank design was set to 17 July, not including the prototype building and armament testing, which were set as late as October of the same year.

Yet, in an unanticipated turn of events, on 7 April 1941, the GABTU rethought the requests on the KV-4. The weight was raised to 75 tonnes, and armor as thick as 135 mm. Side and rear armor was to be 125 mm thick. The blueprints’ deadline was also narrowed, to 15 June. It was at this time that the KV-5 was requested, a tank that was to weigh at least 90-tonnes, have 170 mm of armor at the front and 150 mm at the sides. Additionally, the KV-3 was ‘revived’ and improved to fulfill a stopgap role until the KV-4 and KV-5 tanks were ready for production.

At LKZ, the SKB-2 design bureau began work on 10 April. Head of the project was the famous J. Y. Kotin, who, after seeking approval and funding from factory director I. M. Zaltsman, decided approach the design of the tank in an unusual way, by creating a competition between the SKB-2 engineers. The top few designs would get a financial rewards. Over 20 engineers competed, submitting over 20 individual designs. The winning design was that of N. L. Dukhov, which was essentially an enlarged KV-220. Second place went to the K. I. Kuzmin, V. I Tarotko and P. S. Tarapatin trio, who submitted a tank with the main gun in the hull and secondary gun in a small turret. Third place went to N. V. Tseits, who submitted a tank with a very low hull, but large turret, to offset the lack of hull space.

N.V. Tseits

Nikolai Valentinovich Tseits* was born in Moscow in 1884 and studied engineering at the Bauman Moscow State Technical University, graduating in 1922. In 1925, he started working at the Ordnance-Arsenal Trust and from 1928 onwards worked in the Kazan German-Soviet tank facility. In 1930, he was arrested on counter-revolutionary charges and sentenced to 10 years in labor camps, but the charges were dropped in 1932, after working at a automobile and tractor design bureau. From 1934, he worked at the experimental plant No.185 and, from 1937, at the SKB-2 design bureau of LKZ, where he was the oldest, most knowledgeable and, in turn, most respected engineer. Through his tank design career, he worked on the T-28, T-29, T-35, SMK, KV-3, KV-5, and, lastly, the KV-13. In 1942, after working non-stop for months on the KV-13, he was granted 1 week leave by head engineer J. Y. Kotin, which he used for hunting. Upon his return to ChKZ in Chelyabinsk, he felt unwell and died shortly after at the factory medical office from an unidentified cause. According to the memoirs of N. F. Shashmurin, who was in the room before his death, Tseits had gifted him a slide ruler to remember him by. Tseits was 68 years old at the time. He was awarded the Order of Lenin and Order of the Badge of Honor.

*the spelling Tseits is an anglicized version of the Cyrillic name Цейц.

Nikolai Valentinovich Tseits.
Source: Wikimedia commons

Design

In terms of general layout, Tseits kept his design traditional, with the engine towards the rear and turret in the center of the hull. What was not traditional, at least for a Soviet tank, was the final drive, which had been moved to the front, as opposed to having it combined with the engine. Another unusual feature was the very low hull roof. In order to offset the low hull, the turret was large in all directions, so much so that it had to be ‘lowered’ into the hull, with the turret ring being below the level of the driver’s head. The height of the turret allowed for the main gun ammunition to be stowed vertically, in great numbers, with 100 to 120 rounds stowed on the turret side walls and underneath the turret ring. A secondary turret was placed on top, armed with a DT 7.62 machine gun.

The 1,200 hp M-40 engine, with 4 TK-88 turbochargers, was housed at the rear of the hull, resembling modern MBTs, as opposed to a design from 1941. The air cooling was directed via a protruding chamber, at the rear, as opposed to a curved plate, as on most KV tanks. The driveshaft ran from the engine over the torsion bars and underneath the fuel tanks that were in the center of the hull, underneath the turret ring. The final drive, brakes and gearbox were placed at the tip of the hull, at the feet of the driver and bow machine gunner.

Side view of Tseits’ KV-4 design. Note just how short the hull is in comparison to the turret height.
Source: ASKM

Top view of Tseit’s design. The circular turret can be seen, as well as part of the ammunition layout.
Source: ASKM

Crew

As designed, the tank was to have a crew of 7 men: commander, main gunner, main loader, loader assistant, driver, bow machine gunner and radio operator/secondary turret operator.

Unfortunately, exact positions for all the crewmen are not given, so some speculation is required. The driver and bow machine gunner were both seated inside the hull. Here, the hull roof was lifted to allow for placement of the 7.62 mm bow machine gun in a ball mount and to give room for the 2 crewmen’s heads. The driver had 3 periscopes for vision, in addition to the vision slit in the hull. The rest of the crewmembers were likely placed in the roomy turret. The gunner was to the left of the gun and the commander to the opposite side, on the right. Behind them were the 2 main loaders, each tasked with loading the gun from the opposing sides of the turret walls. The ammunition stowage did not have any rotation system, similar to later autoloaders, thus requiring several loaders to reach all sides.

Armor

The turret was made from curved armor plates into a semicircle 125 mm thick. The only exception was the front of the turret, which consisted of a single, angled, flat plate, 130 mm thick. On it was the gun mantlet. The roof of the turret was partly angled at the front and 50 mm thick. The lower frontal plate was 130 mm, as was the front of the driver’s cubicle. The upper frontal plate, angled very steeply, sas just 50 mm thick. Hull sides and rear were 125 mm thick. Other areas were 50 to 40 mm thick.

Armament

The main armament was the ZiS-6 107 mm gun, previously named F-42. It was designed by the famous V. G. Grabin in record time at Stalin’s personal request for the new heavy tanks. The gun was tested, after many delays, in June 1941 on a KV-2 with a KV-3 mantlet, and after good performances, entered production. According to Grabin’s memoirs, around 800 barrels had been built, and subsequently melted down after the failure of the KV-3, KV-4. and KV-5 programs. The gun could fire an 18.8 kg one-piece shell at 800 to 840 m/s.

KV-5

Tseits’ design was greatly appreciated and placed 3rd in the competition, losing only to Dukhov’s design and the design by the K. I. Kuzmin, V. I. Tarotko, and P. S. Tarapatin trio. However, shortly after, the latter design, which placed second, was ‘disqualified’, likely due to the design not respecting original technical specifications and requirements. This, in turn, moved Tseits’ design up to second place.

On 7 April, in addition to changing the specifications of the KV-3 and KV-4, the GABTU requested an entirely new tank, larger and heavier than the already 80 to 90 tonne KV-4. It was to weigh at least 90 tonnes, have armor as thick as 170 mm at the front and 150 mm at the sides. J. Y. Kotin initially intended to start its development in the same way as on the KV-4, via a competition between engineers. But, as the requirements were similar (and equally vague) to the KV-4, it was decided to save time and use the results from the KV-4 competition. As a result, Tseits’ design, now being on second place, was chosen as the basis for the KV-5, and N.V. Tseits was chosen as senior machine designer of the project. Other engineers that placed high in the competition were given different roles in designing different segments, such as K.I. Kuzmin (head of design group), L. E. Sychev, A. S. Ermolayev, L. N. Pereverzev, and V. Bykov among others.

The design was kept very similar to Tseits’ KV-4 design, such as the large turret and low hull, but major changes were made, including moving the final drive to the rear, making the turret a pentagonal shape (much easier to weld straight plates compared to stamping them into a curve), as well as the driver and bow machine gunner being seated into individual ‘pods’.

Original blueprints of the KV-5 showing the hull.
Source: ASKM

Conclusion

The KV-4 design created by N.V. Tseits was, arguably, the most successful KV-4 design. While N.L. Dukhov’s design did win the competition and was to become the final variant of the KV-4, Tseits’ design was the basis of an even more powerful tank, in the form of the KV-5. However, considering the KV-5s nearly pointless birth, short life and unmourned death, it is not much of a gratification to a series of projects considered by the designers themselves as madness.

Interpretation of Tseits’ KV-4 design by Pavel Alexe. Illustration funded through our Patreon campaign.

KV-4 Tseits Specifications
Dimensions (L-W-H)	8.85 – 4.03 – 3.62 m
Total Weight, Battle Ready	90 tonnes
Crew	7 (Commander, gunner, driver, machine gunner, radio operator, loader, turret mechanic/loader assistant)
Propulsion	1,200 hp diesel V-12 M-40 with 4 turbochargers
Speed	45 km/h (hypothetical)
Armament	107 mm ZiS-6 (F-42) 2x 7.62 mm DS-39 machine guns Unspecified flamethrower
Armor	Front hull upper plate: 50 mm Front hull bottom plate: 125 mm Turret front:130 mm Side plate: 125 mm Top and belly: 50 mm
Total Production	0, blueprints only

Sources

Breakthrough tank KV – Maxim Kolomiets
Supertanki Stalina IS-7 – Maxim Kolomiets
KV 163 1939-1941 – Maxim Kolomiets
Confrontation – Ibragimov Danyial Sabirovich
Bronevoy Schit Stalina. Istoriya Sovetskogo Tanka (1937-1943) M. Svirin
About the forgotten creators of Soviet armored power. (historyntagil.ru) – S.I. Pudovkin
German Lion | Warspot.ru – Yuri Pasholok
Tank building on the verge of common sense | Warspot.ru – Yuri Pasholok
Large caliber for large HF | Yuriy Pasholok | Yandex Zen – Yuri Pasholok
Tank Archives: Soviet 107 mm Guns – Peter Samsonov
Tank Archives: KV-3 Mulligan – Peter Samsonov
Tank Archives: Heavy Tank Costs – Peter Samsonov
Tank Archives: ZIS-6 Characteristics – Peter Samsonov
Танкостроение на грани здравого смысла | Warspot.ru
Branch of RGANTD | (archive.org)
About the forgotten creators of Soviet armored power. (historyntagil.ru)
Revolution Dingxin (1) – I love to look at the bib (wakwb.com)
Tanks are a war of minds. Designer of combat vehicles (wikireading.ru)

Cold War Romanian Armor

TMA-83 and TMA-79

TMA-83. Illustration by Pavel Alexe, funded through our Patreon campaign.

Socialist Republic of Romania (1984-1990)
Medium Artillery Tractor – 200+ Built

The TMA-83 (Tractor Mijlociu de Artilerie, Eng: Medium Artillery Tractor) was a Romanian medium artillery tractor meant to replace Soviet artillery tractors in service, but also work side by side with Soviet counterparts, namely the ATS-59 and ATS-59G. However, due to mechanical problems with the transmission, it was seen as inferior to its Soviet counterparts and was quickly retired.

Development

Throughout the 1950s, of the Romanian military, which, up until then, was just junk and leftovers from the Second World War, underwent a radical restructuring. During this period, various Soviet artillery pieces were purchased, including, among others the 122 mm A-19 and 152 mm ML-20 howitzers. However, by the 1970s, after the deterioration in the relationship between Romania and the Soviet Union, the country set out to build its own artillery pieces. Work began in the late-1970s and. By the 1980s, several howitzers had been created, including the 130 mm Ob.Md.1982, 152 mm Ob.Md.1981 and 152 mm Ob.Md.1985, after licenses from China and USSR. During the 1970s, Romania also purchased newer artillery tractors from the Soviet Union in the form of the ATS-59 and ATS-59G. Previously, artillery prime movers used by Romania were the light AT-L and heavy AT-S 712 and trucks, such as the ZiS-150, which were all growing increasingly obsolete and worn out.

In the mid-1970s, the program to develop domestic artillery tractors based on proven, existing technology began. Thus, the Institutul de Cercetare și Inginerie Tehnologică al Armatei din București (Eng: the Army Development and Technological Engineering Institute in Bucharest), or ICITA, began work on a light artillery tractor based on the Soviet AT-L. The result was the TAR-76, which entered service in 1977, and was intended to tow 122 mm and lower caliber weapons. In 1978, ICITA designed a medium artillery tractor, known as the TMA-79. It used components, such as the engine and running gear, from the ATS-59, but the transmission came from the AT-S 712. One prototype was built at the 102nd Truck and Tank Maintenance Base (nowadays 102nd Maintenance Battalion) in Bucov, in 1979. But, after testing, the vehicle was found to be mechanically unreliable. Thus, the mechanics were reworked, and the vehicle was renamed to TMA-83, and entered production at the Mizil Mechanical Factory in 1984. The first vehicles were delivered to units in 1985.

The TAR-76 light artillery tractor exhibited at the National Military History Museum Ferdinand I in Bucharest. Source: Maquetland

TMA-79

Originally, the TMA-79 medium artillery tractor was intended to be a larger version of the TAR-76 with a 4-door cabin. It used the main components of the Soviet ATS-59, but the conversion was made by switching the hull around (the final drive and sprocket were now in the rear) moving the engine to the front, splitting the frontal section of the cabin in half. Thus, a radiator and air intake were added to the front of the cabin. The main advantage of this was that it now had room for 8 men, including the driver, their personal weapons, food rations, radio, and personal gear. The driver and vehicle commander sat on individual seats on opposite sides of the engine compartment, while the remaining 6 soldiers sat on benches facing each other. Additionally, the cabin was thermally insulated with polystyrene, but not CBRN (Chemical, Biological, Radiation, Nuclear) protected via pressure difference, as on the Soviet ATS-59G. On the roof of the cabin, 2 ports were placed, one for the passenger to the right of the engine (usually commander) and one to the passenger behind the driver. Unfortunately, the conversion seems to have been complex, and while it gave advantages even over the ATS-59G, only 1 has been confirmed to have been built. The larger cab did not compromise the area of the flatbed, which was the same as on the ATS-59, essentially using what was ‘dead space’ on the Soviet counterpart.

The vehicle was, however, plagued by a series of mechanical issues. Moving the sprocket, final drive, and entire power transmission to the back, as well as moving the engine and transmission forwards, caused a series of mechanical issues, mostly with the AT-S 712 transmission and the clutch.

One of the few photos of a TMA-79 with the 4-door cab and front mounted engine. Note the rear drive sprocket, as opposed to the frontal one on the TMA-83.
Source: Artileria Română în Date şi Imagini, colorized by Smargd123

Instead of fixing the issues found on the TMA-79, it was decided that it would be faster and cheaper to simply use the readily available chassis found on the ATS-59. As it had the engine mounted in the center of the hull, above the 2nd and 3rd roadwheels, the cab was shortened to a 2-door one, with just 5 seats inside. The front of the cab was also redesigned, with a simple flat face.

TMA-83 Design

As the chassis of the ATS-59 was used, the running gear and lower hull were identical. The driver, on the left side of the cabin, would control the vehicle with 2 tillers, which in turn actuated the 2 clutch multidisc planetary brakes for the final drive. The TMA-83 had a 2-door cabin that could house 5 men on 2 rows, 2 men on each side of the engine, and 3 on a bench behind it. The engine placement was the same as on the original Soviet platforms, in-between the cabin and flatbed. The front of the cabin had a flat, simple face, with 3 horizontal outward grooves. One roof hatch was given to the front-right passenger, usually the vehicle’s commander. This would be used for guidance and communications during maneuvers and for self-defense using personal weapons.

TMA-83 at the Arsenal Park. Note the smaller 2-door cab and centrally-mounted engine, as on the ATS-59. This vehicle also has a dozer blade from an ATS-59G.
Source: Flickr

Soviet ATS-59G at the Romanian military museum Ferdinand I.
Source: Author’s collection

The engine was produced at the Timpuri Noi factory, on the outskirts of Bucharest. It was the D 199-12 V, a direct-injection V-12 diesel with a maximum power of 360 hp at 2,300 rpm. Maximum torque was 1,280 Nm at 1,600 rpm. The gearbox was a planetary disc with 5 forward and 1 reverse gears. Transmission between the engine and gearbox consisted of 2 axles, one of which was connected to a hydrostatic pump which transferred power to the cable winch, and the other axle was connected to the final drive. A preheating system was installed for easier starting of the engine during low temperatures. In case of failures, a manual starter motor had been included. It allowed for one person to start the engine by hand cranking the camshaft at 60 rpm, which was converted into the 200 rpm necessary for starting the engine. Maximum speed was 52 km/h, however, this decreased to 42 km/h when loaded with crew, ammunition, and towing an artillery piece, and further lowered to 25 km/h when driving over rough terrain.

On the flatbed, 4 men could be transported and the necessary ammunition for the towed artillery piece. There was an alarm installed in the cab for notifying the driver if the system towed had unattached by accident. The empty vehicle weighed 15.8 tonnes. The maximum weight on the flatbed was 4 tonnes, while the maximum towing weight was 15 tonnes and the maximum winching weight was 12 tonnes.

Variants

As it was intended to be the mainstay for the Romanian artillery tractor park, a few variants were thought out and made on the base of the TMA-83. These were designed and built at the 102nd Maintenance Base. However, due to the unreliability of their base chassis and the unfortunate political time when these vehicles were created, very few were made.

MHS-125

Developed in the mid-1980s, the MHS-125 (Macara Hidraulică pe Senile, Eng: Tracked Hydraulic Crane) was a tracked crane that used the chassis of the TMA-83. The cabin was changed to a smaller glass one for better vision when operating the crane. The engine had also been moved to the back for more operational room for the crane. A total of 4 telescopic arms were mounted on each corner of the chassis for stabilization during lifting operations. The crane itself was a HT-125, built at the Timișoara Mechanical Factory, which was mostly used for civilian vehicles. It had a maximum payload of 12.5 tonnes when the arm was retracted and elevated at 60°, though the range was just 2.25 m. The maximum range was of 11.2 m, achieved when the arm was fully extended and angled at 0°, although the payload decreased to just 1.8 tonnes. Of the few made, some are still used by units, but most have been sold to private collectors.

MHS-125 mobile crane. Note the cabin and rear mounted engine.
Source: Unknown

MST-802

An attempt from 1987 to make a domestic trench digging machine, the MST-802 (Mașină de Săpat Tranșee, Eng: Machine for Trench Digging) used the TMA-83 chassis. However, the cabin was cut in half to create a one-man glass cabin. The trench digging apparatus was of Soviet origin, borrowed from a BTM-3. It could dig trenches between 270 to 810 m long per hour. Series 0 of production was to start in 1988, but due to performance issues, homologation was postponed until 1990, when the hydraulic installation was reworked. But the original chassis of the TMA-83 proved to be unsuited for the task of a trencher, as the hull sides would warp under the immense stress caused by the trenching operation, and the overall hull was found to be too narrow. Further work on a domestic trencher was to continue through the 1990s, but budget cuts ended all work.

The only available photo of the MST-802, with its trencher extended. Note the 1-man cabin.
Source: Unknown

Replacement

The TMA-83s were used for towing various heavy howitzers and ammunition. They were also used for accessing remote communities during heavy snows and flooding. According to former mechanics, they were fine machines, when they worked. The main problem was the clutch, which failed often, but the entire transmission proved troublesome. Another issue was the very high fuel consumption. Thus, only 5 years later, when the Communist regime fell and military budgets were cut, the TMA-83 began retirement, as the money was no longer there to keep maintaining and repairing them, as well as satisfy their high fuel consumption. The last examples were retired in 2005. A similar fate was shared by most tracked artillery tractors in Romanian service.

The DAC 665T 6×6 truck first entered production in 1978 and worked hand in hand with artillery tractors in terms of towing and supplies. But, in the 1990s, as they were much cheaper to operate, faster and more reliable, they began replacing the tracked prime movers. In the mid-1980s, the 8×8 DAC 31.320 VFAEG was introduced, and was intended to tow heavy artillery pieces, as well as towing tanks, but only 16 were built. A dozen ATS-59G are still in service in the Romanian forces, towing the Ob.Md.1985, which is too heavy for the DAC-665T to tow.

All TMA-83s were retired by 2005, as Romania joined NATO and retired vast amounts of older equipment. At the moment, at least 4 are put for public display, 2 at the military museum in Constanta, and another 2 at Arsenal Park in Orastie.

ATS-59G towing a Ob.Md.81 near Suceava, 2021.
Source: MApN Facebook

Comparison of some artillery prime movers in Romanian service
Name	AT-S (712)	ATS-59	ATS-59G	TMA-83
Type	Medium artillery tractor	Medium artillery tractor	Medium artillery tractor	Medium artillery tractor
Country of origin	USSR	USSR	USSR	Romania
Production (year)	1950-1962	1959-1967	1969-1980s	1984-1990
Service in Romania	1950s-2005	1960s-2005	1970s-present	1985-2005
Mass (kg)	12,000	13,000	13,750	15,800
Engine (hp)	275	300	300	360
Fuel consumption (l/100km)	156	150-160	150-160	>100
Range (km)	350	350 (500 with external fuel tanks)	350 (500 with external fuel tanks)	530
Max. speed (km/h)	36	41	45	52
Pulling weight (kg)	14,000	14,000	14,000	15,000
Capacity (cabin + flatbed)	7+10	2+14	6+12	5+4

Conclusion

The TMA-83 was a legitimate attempt to nationalize medium artillery tractor production by using readily available and proven components. However, it was plagued by a series of mechanical issues relating to the gearbox and clutch. Additionally, the overall class of tracked artillery prime movers became more and more obsolete, as they were slow, cumbersome, and expensive to maintain. In contrast, trucks became more and more versatile, and eventually replaced tracked prime movers in most militaries.

TMA-83. Illustration by Pavel Alexe, funded through our Patreon campaign.

TMA-79. Illustration by Pavel Alexe, funded through our Patreon campaign.

TMA-83 Specifications
Dimensions (L-W-H)	6.88- 2.70- 2.68 m
Total weight, battle-ready	15,800 kg
Crew	12 (8 in cabin, 4 in flatbed) (TMA-79) 9 (5 in cabin, 4 in flatbed) (TMA-83
Propulsion	360 hp D 199-12 V12
Speed	52 km/h
Suspension	Torsion bar, 5 wheels per side
Armament	N/A
Armor	N/A
No. Built	Around 200 built

Sources

Artileria Romana in date si Imagini – Col. conf. Univ. Dr. Adrian Stroea, Lt. Col. Gheorghe Băjenaru
Tractorul Mijlociu de Artilerie Românesc – Major Eng. Eugen Petre
Sasiu Multifunctional de Geniu – Lt. Col. Eng. Pompiliu Bolan, Eng. Ilie Nicolae
(PDF) Contribuții la istoria dotării cu armament a armatei române între 1944 și 1959 | Sămușan Alin Bogdan – Academia.edu
(DOC) Evoluția dotării cu automobile a armatei române între 1948 și 1957 | Sămușan Alin Bogdan – Academia.edu
(PDF) Motorizarea tracțiunii în armata română între 1948 și 1957 | Sămușan Alin Bogdan – Academia.edu
Tun-obuzier cal. 152 mm (arsenal.ro)
Tractor ATS-59 | Encyclopedia of Military Equipment (war-book.ru)
SAGETILE DACIEI (2) – Romania Military (rumaniamilitary.ro)
Tractor AT-S | Encyclopedia of Military Equipment (war-book.ru)

WW2 Soviet KV-4

KV-4 (Object 224) Mikhailov

Post author By Pavel Alexe
Post date August 3, 2022
2 Comments on KV-4 (Object 224) Mikhailov

P. P. Mikhailov's KV-4 proposal. Note the cylindrical turret and sideskirts. Illustration by Pavel Alexe, funded through our Patreon campaign.

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

The KV-4 program started in spring 1941 as the response to rumors of German heavy tank development. A design competition between engineers at LKZ in Leningrad was held, with several designs awarded, though most others were ignored. One of these was the design proposed by P.P. Mikhailov, which brought several innovative features to the table, such as tracks within the hull, conical turret, and sideskirts. Who P.P. Mikhailov was, and his role at LKZ, is yet to be uncovered.

Development

–Dear reader: A more detailed development analysis of the KV-4 program can be found in the KV-4 Dukhov article–

KV-4 designs

Placement	Name	Mass (t)	Dimensions (m) (LxWxH)	Armament	Crew	Top speed (theoretical)	Armor	Reward /Rubles
1	Dukhov KV-4	82.5	8.150 3.790 3.153	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DT machine guns	6	40 km/h	Front top plate: 135 mm Front bottom plate: 130 mm Side plate: 125 mm Top and belly: 40 mm	5000
2	Kuzmin, Tarotko, Tarapatin KV-4	88	9.26 3.78 3.175	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DS-39 machine guns	6	36 km/h	Front: 125 mm Side: 125-100 mm Top and belly: 40 mm	3000
3	Tseits KV-4	90	8.85 4.03 3.62	107 mm ZiS-6 2x 7.62 mm DS-39 machine guns Unspecified flamethrower	7	45 km/h	Front hul upper plate: 50 mm Front hull bottom plate: 125 mm Turret:130 mm Side plate: 125 mm Top and belly: 50 mm	2800
4	Sychev KV-4	95 – 100	9.23 4.00 3.40	107 mm ZiS-6 (F-42) 45 mm 20-K 2x 7.62 mm DT machine guns	6	40 – 45	Turret: 135-125 mm Hull: 105 mm Top and belly: 40 mm	2000
4	Ermolaev KV-4	90	8.22 4.00 3.25	107 mm ZiS-6	6	35	130 mm
4	Ermolaev KV-4	95	8.52 4.00 3.25	107 mm ZiS-6 45 mm 20-K	6	35	130 mm	2000
5	Shashmurin KV-4	92	9.50 4.00 3.85	107 mm ZiS-6 (F-42) main cannon (112 or 102 rounds) 76 mm F-11 secondary cannon (120 rounds) 2x 7.62 mm DT machine guns (400 rounds) Unspecified flamethrower (hull)	7	35 km/h	Front top plate: 125 mm Side plate: 125 mm Top and belly: 50 to 40 mm	1500
6	Buganov KV-4	93	7.70 3.80 3.90	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front 125 mm	1000
6	Moskvin KV-4	101	9.573 4.03 3.74	107 mm ZiS-6 45 mm 20-K	6	40 km/h	Front 130 mm	1000
7	Pereverzev KV-4	100	9.5 3.8 3.82	107 mm ZiS-6 45 mm 20-K 2x 7.62 mm DT machine guns	6	39 km/h	Front: 125 mm	500
7	Bykov KV-4	98.6	9.5 4.03 3.65	107 mm ZiS-6 45 mm 20-K 7.62 mm DS-39 machine gun	8	36 km/h	Front 130 mm	500
7	Kalivod KV-4							500
N/A	Fedorenko KV-4	98.65	8.10 4.03 3.70	107 mm ZiS-6 45 mm M.1938 3x 7.62 mm DT machine guns Unspecified flamethrower	6	35 km/h	Front upper plate: 140 mm Side plate: 125 mm Turret: 125 mm Top and belly: 50 to 40 mm
N/A	Kreslavsky KV-4	92.6	9 4 3.225	107 mm ZiS-6 45 mm Mod.1937 20-K coaxial 3x 7.62 mm DT machine guns	6	45 km/h	Turret: 130 mm Front hull plate: 130 mm Front upper plate: 80 mm Side plate: 125 mm Rear plate: 130 mm Top /bottom: 50 -40 mm
N/A	Kruchenykh KV-4	107.7	9.13 4.03 3.78	107 mm ZiS-6 45 mm 20-K 4x 7.62 mm DT machine guns	9	30 km/h	Front: 130 mm
N/A	Mikhailov KV-4	86.5	9 3.6 3	107 mm ZiS-6 (F-42) 45 mm Mod.1937 20-K (hull-mounted) 3x 7.62 mm DT machine guns	6	50 km/h	Turret: 130 mm Hull: 130 mm Belly and belly: 50 – 40 mm
N/A	Marishkin KV-4	86.4	8.7 3.6 3.5	107 mm ZiS-6 45 mm 20-K	7	40 km/h	Front: 130 mm Upper frontal: 80 mm
N/A	Pavlov & Grigorev KV-4	91	8.5 4.0 3.6	107 mm ZiS-6 45 mm 20-K	6	45 km/h	Front: 100 – 125 mm
N/A	Turchaninov KV-4	89.5	9.8 4.0 3.0	107 mm ZiS-6 45 mm 20-K DT machine gun	7	35 km/h	Front: 125 mm
N/A	Strukov KV-4	92	8.6 4.0 3.8	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front: 80 – 130 mm
N/A	Unknown KV-4
N/A	Unknown KV-4

The KV-4 program was born from a letter sent by the Soviet Intelligence Services to the Soviet military. This letter, sent on 11 March 1941, had information regarding a German heavy tank, weighing 90 tonnes, and armed with a 105 mm gun. The Main Directorate of Armed Forces (GABTU) was alarmed, as the heaviest tank in Soviet service was the 45 tonnes KV-1, which at the time was mechanically unreliable, and entirely unfit for production. Over at LKZ (Leningrad Kirov Factory) in Leningrad, at the SKB-2 design bureau, where the KV-1 was created, several heavier tanks had been designed, such as the KV-220 and KV-3, but these were still no match for the suspected German heavy tank.

Thus, on 21 March, the GABTU sent LKZ the original requirements for the KV-4. It was to weigh around 70 tonnes and armed with the 107 mm ZiS-6 in a turret and a 45 mm 20-K in a secondary turret. The engine was to be a 1,200 hp enhanced aviation diesel V-12 M-40. Armor was set between 130 and 120 mm at the front, sides, and rear. On 27 March, the deadline for the complete blueprints was set to 17 July.

However, by 7 April, the requirements were changed again. The KV-3 was to be revived, and its specifications vastly improved. In turn, the KV-4 would also weigh 75 tonnes, and have its armor increased to 135 mm. The deadline was also brought forward to 15 June. Most interestingly, LKZ was also assigned the development of the KV-5, a 90 tonne tank, with 150 to 170 mm of armor but also armed with the 107 mm ZiS-6. It would compete against the KV-4, with trials expected to be held in the beginning of 1942. In the meantime, until either entered mass production, the KV-3 would act as a stopgap.

Chief Designer of the program was J.Y. Kotin, who, considering the liberal requirements for the program, decided to approach the design in a unique fashion. He set up a competition between the engineers at SKB-2. For encouragement, he offered financial rewards for the top 7 best designs. By 9 May, the competition was over and the winners were announced. In total, between 24 and 27 proposals were submitted, and 11 prizes were awarded to 13 designers, as several designs were given the same spot and some designers teamed up.

First place went to N.L. Dukhov, second to Kuzmin, Tarotko and Tarapantin, and third to Tseits. Mikhailov’s design was less fortunate, and was one of the many who did not receive any awards for his creation, despite a handful of creative features.

Unfortunately, unlike some of the other competitors, so far, there is no information on who P.P. Mikhailov was, his position at LKZ, what he worked on later on, or his life in general.

Design

In terms of general layout, Mikhailov had a standard approach, with the driver in the hull front, centrally mounted turret, and powerplant package in the rear. Yet the design of these components was very bizarre. The turret was inspired from that of the KV-3, having a large conical shape. Inside, the main 107 mm gun was mounted.

Cutout side view of the design. Note the pattern of the track being forced down by the two return rollers at the base of the hull, right above the roadwheels.
Source: ASKM

The hull is where the design gets more bizarre. The tracks were pushed into the hull, a unique feature, as most Soviet (and modern Russian tanks) have them mounted outside the hull, including the KV-1. Consequently, as moving the tracks inside the hull removed significant usable space the hull, the tracks were forced down onto the roadwheels, instead of laying straight in the center of the hull. This allowed for more space, increasing the hull width in those areas where ammunition and fuel tanks would be placed. Yet the hull was still shorter than many other KV-4 designs. The front of the hull was standard for a KV tank, but the driver and radio operator compartiment were raised in relation to the rest of the hull. The rear was a single plate, stamped into shape.

The KV-4 was powered by a M-40 V12 diesel engine outputting 1,200 hp, also developed at LKZ from 1938 (after the original designer was arrested and killed). It was mounted in the rear of the hull, separated from the crew compartment by a designated firewall. The V12 power plant was coupled to the transmission and final drive, which in turn drove the sprockets. To compensate for the bizarre angling of the tracks and their incorporation within the hull, the air cooling vents had to be angled at the same plane as the tracks, from where the air housing would protrude from the hull. As for air intakes, these were mounted on the engine deck, behind the turret.

Top view drawing of Mikhailov’s KV-4. Notice how the tracks are underneath the hull, and not outside of it.
Source: AKSM

The sprocket and idler were mounted at a “normal” level in relation to the hull. This allowed for adequate angles of attack, and in turn, the off-road capabilities were unharmed by the deviation of the track path. To lower the tracks down, two guide wheels were mounted on the external side of the track. These would also allow for smoother track travel, lowering the chance of the track hitting the hull and potentially hopping out of its travel path. Furthermore, the track’s guide pins would enter the roadwheels, which in turn acted as return rollers. There were 7 roadwheels per side, sprung by torsion bars. These were far larger in diameter compared to the standard KV wheel, while the idler was the same size.

Cutout rear view of Mikhailov’s design. Note the side skirts, which act as the side armor in itself.
Source: ASKM

Crew

The crew was to be of 6, consisting of the tank commander, main gunner, main loader, driver, secondary gun operator, and radio operator. They would communicate with a 10-R intercom.

The commander, main gunner, and loader were placed in the turret, with the gunner to the left of the gun, commander to the right, and loader behind the commander. The loader had to stand up and load the shells mounted in the hull, underneath the turret and to the sides. The drawings only show a single entry/exit hatch, right above the breech of the main gun. If the commander and gunner would not have their own hatches, this would have posed a great issue, not only in emergency exit situations, but in standard service and operation of the tank, with the 3 crewmembers having to wait for the others to enter and exit. The amount of periscopes and/or vision slits is unspecified, but if it were to follow a typical KV design, the commander and gunner would receive their own rotating periscope, in addition to various fixed periscopes around the turret. In contrast to other KV designs, the commander was also the operator of the radio, allowing for direct communication with other tanks.

The driver’s position was to the left of the side of the hull, while the secondary gun operator was to the right. He was quite overburdened, having to aim, fire and load the hull-mounted 45 mm 20-K gun. The two had their own individual entry/exit hatches, situated right above their seats, in the roof of the hull. Notable is that the roof was elevated in their positions, offering more room. The driver also had a ball-mounted DT machine gun. The radio operator was likely situated further in the hull or inside the turret.

Armor

At 86.5 tonnes, it would have been the third lightest design submitted. Yet despite its lower mass and smaller dimensions, it had the thickest plate out of all designs, regarding sheer thickness. The entirety of the turret was 130 mm thick. Measurements of the drawings reveal that the frontal turret plate was 130 mm (the mantlet had the same thickness, resulting in a cumulative of 260 mm). The turret did not have the shape of a homogenous cone, as it was angled at 75º at the front and rear, resulting in 135 mm of effective thickness, and 60º at the sides, resulting in 150 mm. The hull protection was standard, with 130 mm at the front and sides. Here, it is important to highlight that the side armor was on the external side, acting as a side skirt, a feature common on heavy tanks of the 1930s. Belly armor was 50 mm and roof and deck armor was 40 mm. The design of the turret resembles that of the KV-3, but rounder.

Wooden mock-up of the KV-3 tank in its later stages.
Source: Tank Archives

Armament

The main gun, just like on all the other KV-4s, was the 107 mm ZiS-6 gun. It was first designed by V.G. Grabin for the KV-3, after Stalin himself reached out, concerned about the armaments of the KV series of tanks. It was designed in just 38 days, based on the already existing F-42, but renamed ZiS-6. In March of 1941, the Izhora plant was tasked with building a test turret fitting the ZiS-6 in a KV-2. After tests in that summer, the gun was ready to enter production, but the tanks themselves were not ready. It has a muzzle velocity of 88 to 840 m/s and a shell weight of 18.8 kg. Ammunition appears to have been stored exclusively in the hull, underneath the turret. The gun could elevate to +20 and depress to -5. The B-420 rounds had a muzzle velocity of 830 m/s and could penetrate a 120 mm plate angled at 30° from vertical, from 1,600 m. These rounds weighed 18.8 kg.

One of the first ZiS-6 107 mm guns produced.
Source: Yuri Pasholok via Warspot

The secondary armament, a 20-K 45 mm, was mounted in the hull, with limited traverse. Its ammunition was stowed to the right of the gun, in between the track and fuel tank. It used BR-240SP AP rounds, which weighed 1.43 kg, had a muzzle velocity of 757 m/s and a (artificially calculated) penetration of 73 mm at 0 m. An unspecified flamethrower was also mounted in the hull, on the left side over the track.

Drawings of the 45 mm K-20 gun with its turret gun mount.
Source: Armored Wiki via VK.com

Scattered around the tank were three ball-mounted DT 7.62 mm machine guns, one in the hull, operated by the driver, and two in the turret, facing the rear. These would have been operated by the loader and commander, and offered some protection against approaching infantry.

Failed Program

After the competition was completed, progress on the KV-4 virtually halted. The situation worsened when Germany started their invasion of the USSR in June 1941. Work instead shifted to the KV-5, which had complete detailed blueprints by August. However, the German forces were getting closer and closer to Leningrad and the factory workers and engineers were evacuated to ChKZ in Chelyabinsk. The KV-4 and KV-5 programs were canceled, as they would not be of any immediate military use, and divert necessary funds for the war effort.

Conclusion

The entire KV-4 program ended up as a failure, but Mikhailov’s design was not considered as having any beneficial features, and was not taken in consideration or awarded in the competition. Mikhailov did add a series of interesting features, such as bringing the returning track links down, for a wider hull. But one of the most sensible decisions, and unique features of the program, was moving the tracks within the hull altogether, as opposed to having them on the outside. This allowed for a more compact tank and less overall mass.

Special thanks to Zinoviy Alexeev

P. P. Mikhailov’s KV-4 proposal. Note the cylindrical turret and sideskirts. Illustration by Pavel Alexe, funded through our Patreon campaign.

Side view of Mikhailov’s KV-4 with the sideskirts removed, showing the interior of the hull and running gear.

KV-4 Mikhailov Specifications
Dimensions (L-W-H)	9 – 3.6 – 3 m
Total Weight, Battle Ready	86.5 tonnes
Crew	6 (commander, main gunner, driver, secondary gunner, radio operator, & loader )
Propulsion	1,200 hp diesel V-12 M-40 with 4 turbochargers
Speed	50 km/h (hypothetical), 35 km/h (realistic)/td>
Suspension	Torsion bar, 7 wheels per side
Armament	107 mm ZiS-6 (F-42) 45 mm Mod.1937 20-K (hull-mounted) 3x 7.62 mm DT machine guns Unspecied flamethrower
Armor	Turret: 130 mm Front hull plates: 130 mm Side plate: 130 mm Belly: 50 mm Top: 40 mm
Total Production	0, blueprints only

Sources

Breakthrough tank KV – Maxim Kolomiets
Supertanki Stalina IS-7 – Maxim Kolomiets
KV 163 1939-1941 – Maxim Kolomiets
Bronevoy Schit Stalina. Istoriya Sovetskogo Tanka (1937-1943) M. Svirin
Tank building on the verge of common sense | Warspot.ru – Yuri Pasholok
Tank Archives: Soviet 107 mm Guns – Peter Samsonov
Tank Archives: KV-3 Mulligan – Peter Samsonov
Tank Archives: ZIS-6 Characteristics – Peter Samsonov

Cold War Romanian Armor Modern Romanian Armor

TAR-76

The TAR-76 light artillery tractor with the tarp cover mounted. Illustration by Pavel Alexe, funded through our Patreon campaign.

Socialist Republic of Romania/Romania (1977-2005)
Light Artillery Tractor – Around 100 Built

The TAR-76 (Tractor de Artilerie Românesc, Eng: Romanian Artillery Tractor) was a light Romanian artillery tractor meant for towing 122 mm, 152 mm howitzers and their crews, as well as 57 mm AA guns. It was based on recycled Soviet AT-L tractors and used the same running gear and powerpack, but had a larger cabin. Around 100 were produced through the 1970s and 1980s, however, due to the much cheaper operational cost, better reliability, and lower fuel consumption of domestically produced DAC-665T trucks, they were gradually retired after the fall of the Communist regime.

New Artillery

In 1948, the newly formed Romanian People’s Republic (RPR) began the reconstruction of its military. At the time, this consisted of whatever material was leftover from the war, of which the majority was damaged and non-functional. A report from 1950 unveiled that, in terms of artillery howitzers, from those functional to begin with, 55% were from before 1914. Thus, in 1949, with the budget for new armament purchases increased by 900%, and the signing of the “General Costescu” Accord on 4 June 1949, Romania would purchase a wide variety of modern Soviet artillery. Between 1949 and 1950, 84 ML-20 152 mm howitzers and 100 M-30 122 mm divisional howitzers were purchased. To tow the weapons, 22 Stalinets S-80 tractors and 135 ZiS-151 6×6 trucks were purchased, effectively doubling the number of available prime movers within the military. By 1952, another 50 M-30 122 mm howitzers were received. Lighter armament was towed by the 154 ZiS-150 trucks purchased in 1949. By 1957, the RPR had bought 35 AT-L light artillery tractors for towing S-60 57 mm AA guns and 37 AT-S 712 heavy artillery tractors for towing the 152 mm ML-20 howitzers.

Romanian AT-L light artillery tractors towing S-60 57 mm AA guns on 23 August parade, 1964.
Source: Life

It is important to highlight that, during this period, the RPR had just begun the mass industrialisation of a country that previously had no refined industry, and relied mostly on agriculture, raw material exports, and oil. Thus, an array of factories were built with the scope of producing military and automotive products. These factories were based in the halls of the few factories Romania had prior to the war, and whatever was left of them. It was not until after the 1968 Soviet invasion of Czechoslovakia, and Romanian leader Ceausescu’s strong criticism of it, that Romania focused heavily on industrial and military independence, leading to the creation of various domestically designed tanks, APCs, aircraft, helicopters, and ships, though most would be modifications of foreign patents, both of Soviet and Western origin.

Romanian AT-S 712 heavy artillery tractor towing a 152 mm M-20 mod.1937
Source: Cartula

Development

As such, at the beginning of the 1970s, the Institutul de Cercetare și Inginerie Tehnologică al Armatei din București (ICITA) (Eng: the Army Development and Technological Engineering Institute in Bucharest) drew up the specific design of a medium artillery tractor. When designing the vehicle, minimizing reliance on imports and use of existing systems was emphasized. Thus, the running gear and engine of the Soviet AT-L were recycled, but an entirely new larger cabin was added, as well as an all-metal flatbed. The 102nd Truck Maintenance Base (nowadays 102nd Maintenance Battalion) in Bucov was tasked with the initial production of said vehicles, yet the majority were built at the Mizil Mechanical Factory. The military received the first vehicles in 1977.

TAR-76 exhibited at the Military History Museum King Ferdinand I in Bucharest. The golden plate and the L-shaped arm holding it were welded on for the museum.
Source: Maquetland.com

Design

In contrast to popular belief that the TAR-76 was 100% a Romanian designed vehicle, it was actually built upon the chassis of the Soviet AT-L light artillery tractor. The entirety of the track and running gear ensemble remained unchanged. The cabin was lengthened and mounted directly over the engine and gearbox ensemble, splitting the cabin in half. The cabin could house 4 men, including the driver as well as their equipment and radio, and was constructed out of thin sheet metal. It had 2 hatches on the roof for observation and self-defense with the troop’s personal weapons. Each seat had an individual entry/exit door. In the flatbed, 8 soldiers could be carried or dozens of ammunition boxes. The pulling weight capacity was 7.6 tonnes, while the vehicle itself weighed 7.8 tonnes. As the AT-L chassis was used, it had 5 stamped steel roadwheels with rubber padding per side, sprung by torsion bars.

Front view of a TAR-76, without the nighttime masking light covers.
Source: Ebay

The engine was a 135 hp V-6 diesel D120 built at the Timpuri Noi factory in Bucharest. It had a fuel consumption of 80 l/100 km. In terms of steering, the driver had 2 tillers that would control the 2 multi disc clutch brakes. Maximum speed was close to 42 km/h. Fuel reserve was enough for 300 km.

TAR-76 towing an M-10 152 mm howitzer in a promotional video.
Source: Prague Military History Institute

Use and Retirement

Initially, the tractors were used to tow various guns purchased during the artillery restructure of the 1950s, from the heavy 152 mm M-20 and M-10 howitzers and A-19 122 mm howitzer to the 57 mm S-60 AA guns, effectively replacing the AT-L. However, with the beginning of the 1980s, Romania was developing its own field howitzers, the most common being a variant of the Soviet D-20 152 mm gun, the Ob. Md.1981, which the TAR-76 ended up towing after the older heavy howitzers were used for training and reserve purposes.

TAR-76 tractors towing Ob. Md.1981, 23rd August parade, 1984. Note the tricolor Romanian roundel on the door.
Source: Agerpres

In parallel with the development and production of the TAR-76, in the 1970s and 1980s, the Romanian military would purchase the ATS-59 and ATS-59G prime movers from the Soviet Union for towing heavy artillery. While the TAR-76 and ATS-59 would often work together and be used for the same roles, the ATS-59G inspired the development of a heavier Romanian artillery tractor. After just 3 years, the TAR-76 was taken out of production to make place for the TMA-79 (Tractor Mediu de Artilerie Eng: Medium Artillery Tractor) but it was delayed because of mechanical issues, and entered production in only 1984, as the TMA-83. Heavier and stronger, it offered a wider and more versatile platform, and it formed the base for various engineering vehicles, such as the MHS-125 crane and MST-802 trench digger.

Comparison of some artillery prime movers in Romanian service
Name	AT-L	TAR-76	ATS-59	DAC-665T
Type	Light artillery tractor	Light artillery tractor	Medium artillery tractor	6×6 transport truck
Country of origin	USSR	Romania	USSR	Romania
Production (year)	1947-1967	1978-1981	1959-1967	1978-1990s
Service in Romania	1955-1970s	1978-2005	1960s-2005	1978-present
Mass (kg)	5,800	7,800	13,000	5,800
Engine (hp)	135	135	300	215
Fuel consumption (l/100km)	100	80	150-160	32
Range (km)	400	300-600	350 (500 with external fuel tanks)	800-1,000
Max. speed (km/h)	42	42	41	85
Pulling weight (kg)	6,000	7,600	14,000	5,000
Capacity (cabin + flatbed)	3+8	4+4	2+14	3+4 (8 in flatbed if configured)

Both Romanian artillery prime movers were rather unsuccessful. Despite moderate production numbers, they began retirement as soon as the Communist regime fell and military budgets were decimated. They were unreliable, slow, and had high fuel consumption. They were also considered underpowered, struggling to pull 152 mm howitzers over rough terrain or hills. Even their Soviet counterparts, ATS-59 and ATS-59G, while suffering from the same fundamental issues, were more refined and reliable. Instead, heavy artillery would get towed by the DAC 665T truck, much cheaper, refined, faster, and versatile. The Ob.Md.1981 152 mm howitzer, which is the most used field howitzer, is still towed by DAC 665T trucks to this day. In terms of tracked tractors, only a small number of ATS-59G still operate, towing the 152 mm Ob.Md.1985, which is too heavy to be towed by the DAC 665T.

DAC 665T 6×6 trucks pulling Ob.Md.1981 howitzers, belonging to the 15th Mechanized Brigade “Podu Înalt”, during an exercise in April 2022.
Source: 15th Mechanized Brigade Facebook

Most TAR-76s began to be retired after 1990, partly because large quantities of field artillery were taken out of service, but also because of the aforementioned issues. The last examples were retired in 2005. One vehicle was sent to the King Ferdinand I military museum in Bucharest, where it can be seen today. At least another 2 had been restored at Faur works and sent to Arsenal Park in Orastie. Several other tractors, unable to be scrapped due to their service life not being fully exploited, were donated by the military to several isolated communes for use during meteorological hardships, such as heavy snows. For example, the Mircea Vodă commune in Brăila county received 2 such tractors for snow removal and firefighting. The military still retained a handful of tractors. One is kept in pristine condition, alongside mechanical components and drawings, at the school for tank and auto officer training in Pitești. A TR-125 in running condition and a prototype MLVM are also kept here, amongst others.

A TAR-76 from Arsenal Park used for tourist rides. Note the hatches in the roof.
Source: Nebuloasa.info

Conclusion

Despite the unreliability of the mechanical components, high fuel consumption, and slow speed, the TAR-76 was a legitimately good way to revamp and recycle obsolete AT-L tractors. The Romanian defense industry was still in its infancy, and the TAR-76 was the first domestically produced (or rather, converted) artillery tractor. It served as a basis for the more advanced TMA-83, but which suffered from similar problems. In turn, the entire class of tracked artillery tractors has become obsolete when faced with the considerable improvements of military trucks, like the DAC 665T.

Special thanks to Lt. (r) Aurel Chiriac

Sources

Artileria Romana in date si Imagini – Col. conf. Univ. Dr. Adrian Stroea, Lt. Col. Gheorghe Băjenaru
Tractorul Mijlociu de Artilerie Românesc – Major Eng. Eugen Petre
(PDF) Contribuții la istoria dotării cu armament a armatei române între 1944 și 1959 | Sămușan Alin Bogdan – Academia.edu
(DOC) Evoluția dotării cu automobile a armatei române între 1948 și 1957 | Sămușan Alin Bogdan – Academia.edu
(PDF) Motorizarea tracțiunii în armata română între 1948 și 1957 | Sămușan Alin Bogdan – Academia.edu
Adaptare: Gospodarul îşi face iarna car şi vara, tanchetă | adevarul.ro
ROM – TAR-76 (tracked artillery tractor) : Other – not yet classified (valka.cz)
Tun-obuzier cal. 152 mm (arsenal.ro)
Tractor ATS-59 | Encyclopedia of Military Equipment (war-book.ru)
SAGETILE DACIEI (2) – Romania Military (rumaniamilitary.ro)

TAR-76 specifications
Dimensions (L-W-H)	5.10 – 2.20 – 2.50 m
Total Weight, Battle Ready	7.8 tonnes
Crew	8 (4 in the cabin, including driver, 4 on flatbed)
Propulsion	135 hp diesel D120 V-6
Speed	42 km/h
Suspension	Torsion bar, 5 wheels per side
Total Production	Ca. 100

WW2 Soviet KV-4

KV-4 (Object 224) Fedorenko

Post author By Pavel Alexe
Post date July 13, 2022
2 Comments on KV-4 (Object 224) Fedorenko

The KV-4 design as drawn by S.V. Fedorenko. Illustration by Pavel Alexe, funded through our Patreon campaign.

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

In the spring of 1941, with the alleged new of a new German super-heavy tank under development, the Soviets triggered the development of several heavy tank programs. One of them was the KV-4, or Object 224. The LKZ factory in Leningrad was tasked with developing these via a competition amongst factory engineers. One of them was S.V. Fedorenko, the SKB-2 design bureau armament specialist. Yet despite his knowledge and vast array of tanks worked on, his KV-4 design was not taken into consideration.

Development

–Dear reader: A more detailed development analysis of the KV-4 program can be found in the KV-4 Dukhov article–-

KV-4 designs

Placement	Name	Mass (t)	Dimensions (m) (LxWxH)	Armament	Crew	Top speed (theoretical)	Armor	Reward /Rubles
1	Dukhov KV-4	82.5	8.150 3.790 3.153	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DT machine guns	6	40 km/h	Front top plate: 135 mm Front bottom plate: 130 mm Side plate: 125 mm Top and belly: 40 mm	5000
2	Kuzmin, Tarotko, Tarapatin KV-4	88	9.26 3.78 3.175	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DS-39 machine guns	6	36 km/h	Front: 125 mm Side: 125-100 mm Top and belly: 40 mm	3000
3	Tseits KV-4	90	8.85 4.03 3.62	107 mm ZiS-6 2x 7.62 mm DS-39 machine guns Unspecified flamethrower	7	45 km/h	Front hul upper plate: 50 mm Front hull bottom plate: 125 mm Turret:130 mm Side plate: 125 mm Top and belly: 50 mm	2800
4	Sychev KV-4	95 – 100	9.23 4.00 3.40	107 mm ZiS-6 (F-42) 45 mm 20-K 2x 7.62 mm DT machine guns	6	40 – 45	Turret: 135-125 mm Hull: 105 mm Top and belly: 40 mm	2000
4	Ermolaev KV-4	90	8.22 4.00 3.25	107 mm ZiS-6	6	35	130 mm
4	Ermolaev KV-4	95	8.52 4.00 3.25	107 mm ZiS-6 45 mm 20-K	6	35	130 mm	2000
5	Shashmurin KV-4	92	9.50 4.00 3.85	107 mm ZiS-6 (F-42) main cannon (112 or 102 rounds) 76 mm F-11 secondary cannon (120 rounds) 2x 7.62 mm DT machine guns (400 rounds) Unspecified flamethrower (hull)	7	35 km/h	Front top plate: 125 mm Side plate: 125 mm Top and belly: 50 to 40 mm	1500
6	Buganov KV-4	93	7.70 3.80 3.90	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front 125 mm	1000
6	Moskvin KV-4	101	9.573 4.03 3.74	107 mm ZiS-6 45 mm 20-K	6	40 km/h	Front 130 mm	1000
7	Pereverzev KV-4	100	9.5 3.8 3.82	107 mm ZiS-6 45 mm 20-K 2x 7.62 mm DT machine guns	6	39 km/h	Front: 125 mm	500
7	Bykov KV-4	98.6	9.5 4.03 3.65	107 mm ZiS-6 45 mm 20-K 7.62 mm DS-39 machine gun	8	36 km/h	Front 130 mm	500
7	Kalivod KV-4							500
N/A	Fedorenko KV-4	98.65	8.10 4.03 3.70	107 mm ZiS-6 45 mm M.1938 3x 7.62 mm DT machine guns Unspecified flamethrower	6	35 km/h	Front upper plate: 140 mm Side plate: 125 mm Turret: 125 mm Top and belly: 50 to 40 mm
N/A	Kreslavsky KV-4	92.6	9 4 3.225	107 mm ZiS-6 45 mm Mod.1937 20-K coaxial 3x 7.62 mm DT machine guns	6	45 km/h	Turret: 130 mm Front hull plate: 130 mm Front upper plate: 80 mm Side plate: 125 mm Rear plate: 130 mm Top /bottom: 50 -40 mm
N/A	Kruchenykh KV-4	107.7	9.13 4.03 3.78	107 mm ZiS-6 45 mm 20-K 4x 7.62 mm DT machine guns	9	30 km/h	Front: 130 mm
N/A	Mikhailov KV-4	86.5	9 3.6 3	107 mm ZiS-6 (F-42) 45 mm Mod.1937 20-K (hull-mounted) 3x 7.62 mm DT machine guns	6	50 km/h	Turret: 130 mm Hull: 130 mm Belly and belly: 50 – 40 mm
N/A	Marishkin KV-4	86.4	8.7 3.6 3.5	107 mm ZiS-6 45 mm 20-K	7	40 km/h	Front: 130 mm Upper frontal: 80 mm
N/A	Pavlov & Grigorev KV-4	91	8.5 4.0 3.6	107 mm ZiS-6 45 mm 20-K	6	45 km/h	Front: 100 – 125 mm
N/A	Turchaninov KV-4	89.5	9.8 4.0 3.0	107 mm ZiS-6 45 mm 20-K DT machine gun	7	35 km/h	Front: 125 mm
N/A	Strukov KV-4	92	8.6 4.0 3.8	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front: 80 – 130 mm
N/A	Unknown KV-4
N/A	Unknown KV-4

A letter sent to the Soviet authorities by the Soviet Intelligence Services regarding German tank development on 11th March 1941 included a section on the development of German heavy tanks. Here, 3 different models were described, a 30-tonne Pz.Kpfw.V, a 45-tonne Pz.Kpfw.VI, and lastly, a 90-tonne Pz.Kpfw.VII. Which exact tanks these were is unclear, as the real Pz.Kpfw.VII, nicknamed Löwe, did not appear in official documents until November of the same year. Previous tank designs fitting (loosely) descriptions would be the VK30.01 series, VK36.01 and VK65.01.

The idea of a 90-tonne German tank was alarming and the GABTU (Main Directorate of Armed Forces) would quickly request the development of a new super-heavy tank. It was designated Object 224 or, more commonly, KV-4, as called by the factory that would develop it- the Leningrad Kirov plant (LKZ) at its SKB-2 design bureau. The factory had not only designed the KV-1 and SMK heavy tanks, but also heavier variants, such as the T-150, KV-220, and KV-3.

It is important to note that the heaviest tank in service with the Soviet army at the time was the KV-1 itself, which, once the war broke out, would prove a great disappointment. This came as a result of the political rush to push it into military service, even when it was not completely ready. Thus, KV tanks suffered from constant breakdowns from the poorly designed gearbox. They were slow and crews generally preferred the T-34. The situation reached a point where Stalin himself wanted to remove it from production if the issues would not be fixed. To compound the problems with the KV-1, at the time, it was only equipped with the F-32 76 mm gun, a gun inferior to the F-34 on the lighter and more reliable T-34.

On 21st March 1941, the GABTU requested that the KV-4 would be a 70-tonne heavy tank, armed with the ZiS-6 (previously called F-42) 107 mm gun, a 45 mm 20-K secondary gun, 3 DT 7.62 mm machine guns, and even a flamethrower. Armor was to be as thick as 130 mm at the front and 120 mm at the sides and rear. The engine would be a M-40 1,200 hp V-12 engine, with 4 turbochargers. The crew was to be around 6 men. Only 6 days later, the LKZ plant was ordered to complete the blueprints by 17th July, the Izhora plant to complete the prototype turret and hull by 1st October and Plant No. 92 to deliver the necessary armament by 1st September.

However, by 7th April, the GABTU changed their minds. They would request heavier parameters for the KV-3, up to 68 tonnes and the same ZiS-6, while the KV-4 would be increased to 75 tonnes weight, armor improved to 135 mm at the front and 125 mm at the sides and rear. The deadline was also tightened to 15 June. In the same request, the GABTU requested an even heavier vehicle, the KV-5, with 170 mm at the front and 150 mm at the rear, and weight of 90 tonnes. The sudden changes in design, and the increased time pressure, as well as the pressure of Stalin’s interest in the project served to make the design process more problematic and have knock-on effects.

LKZ began work on the KV-4 on 10th April. The head engineer was J.Y. Kotin. Here, the requirements would be changed once again, placing the mass between 80 and 100 tonnes. Considering the loose specifications, Kotin approached the design in a unique manner. With approval from the factory director I.M. Zaltsman, Kotin would make the design of the KV-4 a competition between the best engineers of the SKB-2 design bureau. To encourage seriousness, the top places would even receive monetary compensation. By 9th May, the competition was over, and up to 27 different designs were submitted by over 23 different engineers. The first place went to N.L. Dukhov, who received the first prize of 3,000 Roubles. Second prize went to a design by 3 engineers working together, K.I. Kuzmin, P.S. Tarapanin and V. I. Tarotko, who split the 3,000 Roubles award. Third place went to senior engineer N.V. Tseits who received 2,800 Roubles. Another 8 designs would receive awards. However, S.V. Fedorenko’s design would not receive any awards for his bizarre but innovative design.

S.V. Fedorenko

Born in Chernihiv in 1907, Sergey Vasilyevich Fedorenko graduated from the Leningrad Polytechnic Institute in 1930. At just 23, he began working at the Krasniy Putilovets tractor plant, later renamed to Kirov Leningrad plant (LKZ). By 1937, he was head of SKB-2 artillery and armament section at LKZ. After the transfer to ChKZ in 1941, he was deputy chief designer, on which he worked on tanks like the IS-4. Post-war, he had various jobs, but would settle down for the last two decades of his life as a teacher on tanks at the KGM institute at the South Ural State University. He would pass away a few hours after holding lectures, in 1986, aged 79.

Working mostly with tank armaments and their implementation, S.V. Fedorenko was the man behind various aiming systems, tank optics, turret turning mechanisms, (he was the designer of the entire gun mount, aiming system and overall integration of the armaments on the first KV-1 U-0 prototype, which had a 76 mm gun and a 45 mm one) as well as the flamethrowers for the KV-8 and KV-8S. He would also work under leadership of N.L. Dukhov on the IS-4. During his career, he was awarded 2 Orders of the Badge of Honour, the Order of the Red Star, the Medal for Labour Valour, the Medal for Defence of Leningrad, and the Medal for Valiant Labour during the Great Patriotic War of 1941-1945.

S.V. Fedorenko while working as a professor on tanks and armament at the South Ural State University.
Source: Sergey Fedorenko – SUSU Encyclopedia

The KV-4 (Object 224) Fedorenko’s Design

In terms of the hull, Fedorenko’s KV-4 design approach was revolutionary, barely resembling that of its forebears. Firstly, the entire front consisted of a large single upper frontal plate, akin to that on the later variants of the IS-2. As for the lower plate, it too was a single plate, stamped to form a curve connecting the upper plate to the hull belly, similar to the style used on the American Sherman tanks. The rear was also unique, with the air intake hole being narrower and composed of two welded plates, as opposed to a single, curved steel sheet, as on other KV tanks. The sides were flat and vertical, forming a simple and efficient internal volume in which to install components as well as to mount the 8 road wheels per side, sprung by torsion bars. The sprocket was in the rear and the idler in the front. Armor on the lower frontal plate was 125 mm thick, while the upper was thinner, at just 100 mm, but being angled at 45°, it had a line-of-sight thickness of circa 141 mm. The side and rear plates were 125 mm thick, but were mostly flat. The driver and radio operator sat next to each other in the hull, with the driver in the centre and the radio operator to his left. To his right, he had the fuel tanks. Direct vision slits were cut through the hull armor. The radio operator had his communication equipment on the side walls, and a ball-mounted DT machine gun in the front.

The engine was the M-40 V-12 diesel engine, with 4 turbochargers, delivering 1,200 hp. A hypothetical top speed was to be circa 35 km/h. Fuel tanks were on the right side wall, next to the driver and ammunition. The engine and fighting compartment were separated by a firewall. It was mounted rather high in the hull, which required a protrusion in the engine deck and belts for the final drive.

Multi-view plans of Fedorenko’s KV-4. The front view shows the unorthodox profile of the vehicle.
Source: ASKM

Cutout view of the hull. Note the ammunition storage racks and fuel tanks.
Source: ASKM

Turret

As an armaments implementation engineer, Fedorenko let his creativity loose when it came to the turret and armaments. The turret had a distinctive and unusual rhomboid shape, allowing for a unique weapons layout and turret positions. It was centrally mounted in relation to the hull, but it had more overhang on the right side of the hull than on the left. The main armament was mounted centrally (with regards to the turret face) and had a coaxial DT machine gun. Behind the gunner’s seat, on the rear turret face, a ball-mounted DT machine gun was added. Additionally, a flamethrower was placed in a ball mount at the ‘corner’ of the turret cheek. Next to it, the tank for ignition fuel was placed, On the opposite side, the turret slanted towards the rear, creating a curved edge. Here, a spherical secondary turret was mounted, armed with a 45 mm gun. This turret would be able to move 360° on the horizontal axis, while the gun itself could elevate to 75°, presumably with an eye to engaging airborne or highly elevated targets, such as on the top floors of buildings. The secondary turret had no gun depression due to the recoil mechanism being mounted as low into the turret as possible. This turret can be seen as similar to a ball turret found in bombers.

Frontal view of the design. Note how the hull has been made as narrow as the engine allows. This causes a significant overhang of the turret.
Source. ASKM

Crew

The tank was intended with a crew of 6, tank commander, main gunner, 2x loaders, driver and radio operator. How exactly the crew operated this turret and how they were seated is unspecified and complex. Estimation and study of the drawings can reveal some possibilities. The gunner was seated to the left of the main gun, but would also be tasked with manning the flamethrower. The first loader would load the gun and probably operate the rear-facing DT machine gun. The commander would likely sit in the secondary turret, where he would not only have better vision but also rotation independent of the main turret. He would operate the 45 mm gun by himself, as the turret is too small to allow for a second crewmember. There are no periscopes drawn in on the secondary turret, so likely eye-level vision slits were intended. The second loader was likely in a position ‘between’ the turret and hull, and would be tasked with passing the ammunition for the various armaments, which was stowed in the hull. The driver and radio operator sat in the hull, with the driver in the center and the radio operator to his left, having a ball-mounted DT machine gun at his disposal.

The bizarre shape of the turret proposed by Fedorenko. Note that the rear-facing machine gun has had the armor pushed outwards to allow for additional room in the turret.
Source. ASKM

Armaments

As required by the state, the main armament was the 107 mm ZiS-6 (previously named F-42) gun, designed by V.G. Grabin a few months prior. It was mounted centrally (with regards to the hull) in the turret, and had a DT 7.62 mm coaxial machine gun. Circa 100 rounds for the main armament were stored in a horizontal ammunition rack placed against the left wall, with 8 more being stored between the torsion bars, running across the floor. The gun had a muzzle velocity between 800 and 840 m/s. Ammunition weighed 18.8 kg and was of the one-piece (unitary) type.

Secondary armament, as required, was a 45 mm 20-K gun model 1938 placed in an independently rotating turret. This iconic weapon was used on the vast majority of Soviet light tanks, such as the BT-7 and T-26, but was obsolete for fighting tanks in 1941. Even so, it would still have had considerable fighting value against lightly armored vehicles and other soft targets, where the ZiS-6 would have been ‘overkill’. Also, with HE rounds, it could have been very effective against infantry. The gun featured an electrical trigger and vertical plane gyroscopic stabiliser. It had a muzzle velocity of circa 760 m/s, and an elevation of 75°. A total of 150 rounds were carried for this gun.

Other weapons scattered around the tank were a coaxial 7.62 mm DT machine gun, a rear-facing DT machine gun in the turret, a ball-mounted DT machine gun in the front hull and a flamethrower of unspecified type in the turret cheek, facing the front. Its implementation was interesting, as it was vaguely required by the GABTU and, as a result, many designers left it out completely.

War!

After the end of the competition, the KV-4 progress was slow and focus shifted more to the drawings of the KV-5. The situation got so bad that on 12th June, Marshall of the Soviet Union G.I. Kulik requested LKZ to speed up work. Yet, just 10 days later, the German invasion of the USSR began. Work continued at LKZ, but the heavy tanks were no longer any priority. Nonetheless, the drawings of the KV-5 were complete by the time the Germans reached Leningrad in August. Then the SKB-2 design bureau would be evacuated to the ChKZ plant in Chelyabinsk. Work on these heavy tanks would not resume.

Conclusion

Fedorenko’s design was one of the many ‘unsuccessful’ KV-4 designs, as he did not receive any placement and monetary awards, though this may seem unjustified. His turret design had one of the most interesting and unusual turret layouts, being a rhomboid. He exploited this unusual shape to mount a variety of weapons in different positions. The hemispherical secondary turret is another interesting addition that did not feature a machine gun, as commonly seen on later tanks, but a full-fledged 45 mm gun. Even the hull had its own merits, employing a flat, slanted upper frontal plate, and elevating the engine deck for a shorter overall hull length. It is safe to say that Fedorenko presented a ‘delicate’ KV-4, as opposed to many other designs which were rawer, though this seemingly did not impress Kotin or Saltzman.

The KV-4 design as drawn by S.V. Fedorenko. Illustration by Pavel Alexe, funded through our Patreon campaign.

KV-4 (Object 224) Fedorenko specifications
Dimensions (L-W-H)	8.10 – 4.03 – 3.70 m m
Total Weight, Battle Ready	98.65 tonnes
Crew	6 (Commander, Gunner, Driver, Radio operator, loader, & turret mechanic/loader assistant)
Propulsion	1,200 hp diesel V-12 M-40 w/ 4 turbochargers
Speed	35 km/h (hypothetical)
Suspension	Torsion bar, 8 wheels per side
Armament	107 mm ZiS-6 (F-42) (110 rounds) 45 mm M.1938 20-K 3x 7.62 mm DT machine guns Unspecified flamethrower
Armor	Front upper plate: 140 mm Front lower plate: 125 mm Side plate: 125 mm Turret: 125 mm Top and belly: 50 to 40 mm
Total Production	0, blueprints only

Sources

Breakthrough tank KV – Maxim Kolomiets
Supertanki Stalina IS-7 – Maxim Kolomiets
KV 163 1939-1941 – Maxim Kolomiets
Confrontation – Ibragimov Danyial Sabirovic
Bronevoy Schit Stalina. Istoriya Sovetskogo Tanka (1937-1943) M. Svirin
Gunsmith S.V. Fedorenko (famhist.ru)
About the forgotten creators of Soviet armored power. (historyntagil.ru) – S.I. Pudovkin
German Lion | Warspot.ru – Yuri Pasholok
Tank building on the verge of common sense | Warspot.ru – Yuri Pasholok
Large caliber for large HF | Yuriy Pasholok | Yandex Zen – Yuri Pasholok
Tank Archives: Soviet 107 mm Guns – Peter Samsonov
Tank Archives: KV-3 Mulligan – Peter Samsonov
Tank Archives: Heavy Tank Costs – Peter Samsonov
Tank Archives: ZIS-6 Characteristics – Peter Samsonov

WW2 Soviet KV-4

KV-4 (Object 224) Shashmurin

Post author By Pavel Alexe
Post date June 17, 2022
4 Comments on KV-4 (Object 224) Shashmurin

Final variant of Shashmurin's KV-4. Illustration by Pavel Alexe.

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

The KV-4 program was launched in the spring of 1941 as a response to the rumor of a German super heavy tank. Thus the LKZ factory in Leningrad was set to design a heavy tank capable of challenging the alleged German tank. A design competition was started, with over 20 different tanks presented by engineers at LKZ. One of them was N.F. Shashmurin, who presented a vehicle with a KV-1 trurret over a casemate which housed the 107 mm ZiS-6 gun. For this design, he was awarded 5th place in the competition. However due to his personal disputes with the chief engineer, J.Y. Kotin, he did not participate in the development of the KV-5.

Development

–Dear reader: A more detailed development analysis of the KV-4 program can be found in the KV-4 Dukhov article—

KV-4 designs

Placement	Name	Mass (t)	Dimensions (m) (LxWxH)	Armament	Crew	Top speed (theoretical)	Armor	Reward /Rubles
1	Dukhov KV-4	82.5	8.150 3.790 3.153	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DT machine guns	6	40 km/h	Front top plate: 135 mm Front bottom plate: 130 mm Side plate: 125 mm Top and belly: 40 mm	5000
2	Kuzmin, Tarotko, Tarapatin KV-4	88	9.26 3.78 3.175	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DS-39 machine guns	6	36 km/h	Front: 125 mm Side: 125-100 mm Top and belly: 40 mm	3000
3	Tseits KV-4	90	8.85 4.03 3.62	107 mm ZiS-6 2x 7.62 mm DS-39 machine guns Unspecified flamethrower	7	45 km/h	Front hul upper plate: 50 mm Front hull bottom plate: 125 mm Turret:130 mm Side plate: 125 mm Top and belly: 50 mm	2800
4	Sychev KV-4	95 – 100	9.23 4.00 3.40	107 mm ZiS-6 (F-42) 45 mm 20-K 2x 7.62 mm DT machine guns	6	40 – 45	Turret: 135-125 mm Hull: 105 mm Top and belly: 40 mm	2000
4	Ermolaev KV-4	90	8.22 4.00 3.25	107 mm ZiS-6	6	35	130 mm
4	Ermolaev KV-4	95	8.52 4.00 3.25	107 mm ZiS-6 45 mm 20-K	6	35	130 mm	2000
5	Shashmurin KV-4	92	9.50 4.00 3.85	107 mm ZiS-6 (F-42) main cannon (112 or 102 rounds) 76 mm F-11 secondary cannon (120 rounds) 2x 7.62 mm DT machine guns (400 rounds) Unspecified flamethrower (hull)	7	35 km/h	Front top plate: 125 mm Side plate: 125 mm Top and belly: 50 to 40 mm	1500
6	Buganov KV-4	93	7.70 3.80 3.90	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front 125 mm	1000
6	Moskvin KV-4	101	9.573 4.03 3.74	107 mm ZiS-6 45 mm 20-K	6	40 km/h	Front 130 mm	1000
7	Pereverzev KV-4	100	9.5 3.8 3.82	107 mm ZiS-6 45 mm 20-K 2x 7.62 mm DT machine guns	6	39 km/h	Front: 125 mm	500
7	Bykov KV-4	98.6	9.5 4.03 3.65	107 mm ZiS-6 45 mm 20-K 7.62 mm DS-39 machine gun	8	36 km/h	Front 130 mm	500
7	Kalivod KV-4							500
N/A	Fedorenko KV-4	98.65	8.10 4.03 3.70	107 mm ZiS-6 45 mm M.1938 3x 7.62 mm DT machine guns Unspecified flamethrower	6	35 km/h	Front upper plate: 140 mm Side plate: 125 mm Turret: 125 mm Top and belly: 50 to 40 mm
N/A	Kreslavsky KV-4	92.6	9 4 3.225	107 mm ZiS-6 45 mm Mod.1937 20-K coaxial 3x 7.62 mm DT machine guns	6	45 km/h	Turret: 130 mm Front hull plate: 130 mm Front upper plate: 80 mm Side plate: 125 mm Rear plate: 130 mm Top /bottom: 50 -40 mm
N/A	Kruchenykh KV-4	107.7	9.13 4.03 3.78	107 mm ZiS-6 45 mm 20-K 4x 7.62 mm DT machine guns	9	30 km/h	Front: 130 mm
N/A	Mikhailov KV-4	86.5	9 3.6 3	107 mm ZiS-6 (F-42) 45 mm Mod.1937 20-K (hull-mounted) 3x 7.62 mm DT machine guns	6	50 km/h	Turret: 130 mm Hull: 130 mm Belly and belly: 50 – 40 mm
N/A	Marishkin KV-4	86.4	8.7 3.6 3.5	107 mm ZiS-6 45 mm 20-K	7	40 km/h	Front: 130 mm Upper frontal: 80 mm
N/A	Pavlov & Grigorev KV-4	91	8.5 4.0 3.6	107 mm ZiS-6 45 mm 20-K	6	45 km/h	Front: 100 – 125 mm
N/A	Turchaninov KV-4	89.5	9.8 4.0 3.0	107 mm ZiS-6 45 mm 20-K DT machine gun	7	35 km/h	Front: 125 mm
N/A	Strukov KV-4	92	8.6 4.0 3.8	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front: 80 – 130 mm
N/A	Unknown KV-4
N/A	Unknown KV-4

On 11th March, 1941, the Soviet Intelligence Services provided a letter to the state discussing the development of German tanks. One of the subsections focused on development of heavy tanks, and showcased 3 main types; a Mark V weighing 36 tonnes and armed with a 75 mm gun, a Mark VI weighing 45 tonnes and armed with a 75 mm gun and 20 mm, and finally, a Mark VII, weighing 90 tonnes and armed with a 105 mm gun and dual 20 mm guns.

This was slightly bizarre, as, during the spring of 1941, the Pz.Kpfw.VII, commonly known as the Löwe, did not exist. It would only appear in documentation in November. Other German heavy tanks however existed, such as the VK30.01, VK36.01 and VK65.01. What exactly was ‘discovered’ by Soviet agents remains a mystery and may have been little more than speculation.

The Soviets only had the KV-1 in service as anything even remotely close to the above mentioned German tanks. Yet the KV-1 was armed with rather lacklustre guns, the 76 mm F-11 and later F-32, and its gearbox would prove very unreliable. The original gearbox was designed by N.F. Shashmurin, but Kotin favored N.L. Dukhov’s gearbox, which proved to be a disaster. Other Soviet heavy tanks, the T-150 and KV-220, were still under development when the news of new German heavy tanks came in. Even so, their development would not continue, as the improvements in armament and armor they would have brought were not seen as significant enough. With hindsight, the KV-220, with its 85 mm L-30 gun and 100 mm of armor, would have been on par with the German Tiger tank entering production in August 1942, well over a year later.

Naturally, the prospect of even more heavily armored and armed German tanks potentially coming out raised an alarm at the GABTU (Main Directorate of Armed Forces), which did not have a heavy tank on par with these parameters. As a result, on 21st March, the GABTU released a set of requirements for a new tank which was to receive the index Object 224 and general name KV-4. This would have a weight of around 70 tonnes, armed with an 107 mm ZiS-6 gun in a fully rotating turret, and a coaxial 45 mm gun. Additionally, at least 3 DT 7.62 mm machine guns and potentially a flamethrower had to be added. Armor was to be 130 mm at the front and 120 mm at the sides and rear. The engine for this new tank was to be one capable of producing 1,200 hp. Unfortunately, there were no engines powerful enough at that moment, so temporarily, a 850 hp V-2SN would be used. The crew was supposed to be of 6 men; commander, gunner, driver, radio operator, and 2 loaders. On 27th March, GABTU requested that the blueprints be finished by 17th July.

However, by 7th April, the requirements were changed. The armor was increased to 135 mm and 125 mm to the front and sides, respectively. With increased armor, the prospective weight of the vehicle was increased to 75 tonnes. Submission date for the blueprints was also brought closer, to 15th June, nearly a month earlier than had been asked for previously and indicating the urgency of the work at hand. It was also on this day that the KV-3 requirements were improved, and the KV-5 was born. Both the KV-4 and KV-5 were expected to enter testing in 1942.

It was the LKZ, Leningrad Kirov Plant, headed by I.M. Zaltsman, that was tasked with designing the new heavy tank. LKZ had previously worked on the SMK, KV-1, T-150 and KV-220 heavy tanks, but none came to the sheer mass and size that the KV-4 had to reach. The lead engineer of the project was J.Y. Kotin. The Izhora plant had to construct a turret and hull prototype, while plant No.92 was tasked with supplying the main gun

Work at LKZ started 3 days later, on 10th April. Since it was an entirely new project with relatively loose requirements, J.Y. Kotin decided to make the general design of the tank a competition between the engineers at the SKB-2 design bureau. The result was that over 24 designs were submitted by 9th May. First place was awarded to N.L. Dukhov, receiving 5,000 Roubles. Shashmurin received the 5th place, with an award of 1,500 Roubles.

Unfortunately, much confusion surrounded the actual winner of the KV-4 competition. This was caused by a segment in N.F. Shashmurin’s memoirs, from which readers interpreted that he had won. This is incorrect, as his design had received 5th place, for which the 1,500 Rubles award was given. Below is the relevant translation. It must be noted that, throughout his memoirs, titled ‘50 years of Confrontation’, Shashmurin makes a series of mistakes and inaccuracies, but this is to be expected, as he wrote it in 1987, 50 years later.

Having received, along with other leading employees at the design bureau (SKB-2), the task of developing a project for such a cyclops*, obviously multi-turreted, I, without sharing the same optimism considering the previous circumstances (multi-turreted, how long ago have we given up on the ‘Muir & Mirrielees’**, crumbled by the SMK) made a ‘knight’s move’. Basically, the turret was removed, and the process as when installing the M-10 152 mm on the KV-1 was repeated, that is, a casemate superstructure on the hull. And since a new, practically super-heavy KV-3 had already been created,*** I decided to not be smart about the ‘supernova’ tank. Having dropped the turret, the process was repeated from previous high-power self-propelled guns, but this time with a 107 mm Grabin gun. Notiyfing in an explanatory note that, under specific conditions, the gun can be removed and instead a rifle squad of infantrymen can be placed in the fighting compartiment. This option was not accepted, as the requirements were not met – (it required) higher protection, weight between 80 – 100 tonnes, turreted (multi-turreted) gun placement. To avoid an unnecessary confrontation, I complied. Considering that a superheavy tank cannot be a (true) tank, to fulfil the specified protection parameters, (I) had to invest into about 90 tonnes, kept the casemate mounted main gun, and installed a serially produced KV-1 turret on the now shortened (casemate) roof. It ended up that I.M. Saltzman really liked the variant, (given its ‘sensibleness’, or as he put it, ‘versatility’) and I received the second prize with the amount of 1000 Roubles.**** That was great. I bought my wife a fur coat with this money.

– Nikolai Fedorovich Shashmurin, extract from ‘50 years of Confrontations’.

*Referring to ancient Greek mythology where Odysseus blinds the giant cyclops Polyphemus.
**Scottish-owned Trading company in then St. Petersburg, started by Muir and Mirrielees, famous for its two devastating fires.
***Probably referring to designs by his fellow engineers.
****Documents from the time prove him wrong. He had in fact received 5th place and 1,500 Roubles.

Interestingly, Shashmurin disliked the KV-4, not only his own creation, but the entire program. According to historian Dr. Gennadiy Petrov, who knew Shashmurin personally, he had written on the back of his drawings the letters Б.С. (B.S.) acronym for Бред сумасшедшего, translating to “delirium of a madman”. This unconfirmed, but plausible detail gives insight to Shashmurin’s long-lived jealousy and dislike for J.Y. Kotin, Chief Engineer at LKZ. His strong feelings were made public again in a magazine interview taken by Sergey Ptichkin in the 1990s, which was mostly aimed at answering questions regarding the shortcomings of the KV-1, though the KV-4 was once again mentioned. A translated extract:

“Instead of eliminating the identified defects (of the KV-1) at the Kirov plant, they (in regards to the GABTU, I.M. Zaltsman and J.Y. Kotin) began to design a series of armored mastodons: KV-3 weighing 65 tonnes, KV-4 – 80 tonnes, KV-5 – 100 tonnes! Regrettably, we showed clear signs of technical madness much earlier than in Germany, where only at the end of the Second World War they tried to create weapons of retaliation like the ‘mouse’ tank, weighing 180 tonnes.* The first days of the Great Patriotic War only confirmed that the KV-1 in the form in which it was produced, was not fit for fighting, since it did not have a reliable powerplant. So there was this tragic paradox; the armor was strong, but it was not a fast tank. It would seem that faith itself pushed for an urgent modernization of the KV, for the replacement of the inoperable gearbox**, but, alas, in the most difficult time for the country, from the end of the summer of 1941 to the spring of 1942, we continued to spend huge material resources and human forces for further scientific and technical research. In the autumn of 1941, an attempt was even made to remove the KV-1 from production and replace it with the KV-3, a powerful, but completely “raw” and unnecessarily heavy machine.”

– N.F. Shashmurin, extract from ‘Soviet Warrior’, interview by Sergey Ptichkin, 1990s.

*With hindsight this is wrong, German superheavy tank development started long before WWII, more or less simultaneously with Soviet superheavy tank projects. However, in pre-internet, post-Soviet Russia, this was not common knowledge.
**The iconically unreliable gearbox and transmission of the KV-1 was a sensible spot for Shashmurin, as he had designed the original gearbox, but the production gearbox was designed by N.L. Dukhov.

In a way, Shashmurin was conservative in regards to tank design. From his post-war works, he made it clear that he preferred a more controlled testing and development of the KV-1, which was more or less rushed into production. He had wished for modernising and improving its faults. He liked the KV-1S but greatly despised the KV-13, which he considered redundant, despite the fact that he was its Chief Designer, after the death of N.V. Tseits, which Shashmurin once again blamed Kotin for. He was also Chief Designer of the IS-2, which he believed was a very worthy tank and should have been upgraded and improved upon, instead of rushing new tanks into production like the IS-3 and IS-4, which he called “impressive but unreliable”.

In hindsight, Shashmurin was correct in this regard. Oddly though, he was very proud of the IS-7, of which he was Chief Designer, and claimed Western tanks would not match its capabilities for decades, and blamed its cancellation on Khrushchev’s* obsession with rockets and missiles.

(*Nikita Khrushchev, First Secretary of the Communist Party of the Soviet Union 1953 – 1964)

Prototype of the SMK, the tank for which N.F. Shashmurin designed the torsion bar suspension.
Source: TsAMO via Maxim Kolomiets

N.F. Shashmurin

Born in 1910 in what was called at the time St. Petersburg, Nikolai Fedorovich Shashmurin started his engineering studies at the Leningrad Polytechnic Institute in 1930, and graduated in 1936. By 1937, he had started to work at LKZ as an engineer for both the SKB-2 design bureau and the VNII-100 research institute. He designed important elements of mechanical components, such as torsion bars and transmissions. Likewise, he worked on the development of the majority of LKZ wartime developed tanks, such as the SMK, KV-1, KV-1S, KV-13, KV-85, IS, and IS-2. Postwar, he worked on tanks like the IS-7 and PT-76, as well as various tractors (LKZ partly resumed civilian tractor production).

By the 1970s, he was a PhD in technical sciences and worked as a professor at the Leningrad Polytechnic Institute. He died in 1996, aged 86. During his career, he received 2 Stalin Prizes, the Order of Lenin, the Order of the Red Star, and the Medal for Victory over Germany during the Great Patriotic War of 1941-1945 (II Degree).

N.F. Shashmurin in the 1930s. He was an important part of many tanks developed at LKZ.
Source: Bronetechnikamira.ru

Shashmurin’s design

Original layout

If his memoirs are to be believed, Shashmurin originally intended to have an enclosed casemate for the main armament, without the additional turret. The casemate would have also been taller, resulting in something akin, a parallel he drew himself, to the KV-1 with M-10 152 mm howitzer. This suggests a much taller casemate to what was used on the final design. The driver and radio operator were likely placed within the fighting compartment, instead of being ‘pushed out’. He had also intended that the gun could be removed and a rifle squad of infantrymen be carried instead. However, this variant was not approved as it was ‘too light’, did not have at least one turret-mounted armament and the armor was too thin.

Final design

When designing his final KV-4 proposal, Shashmurin had a different approach. As per the original state requirements, the main gun had to be mounted in a fully rotating turret, but after the additional requirements (some of which were contradicting with each other) set by the GABTU, several designers decided to install the 107 mm ZiS-6 main gun in a limited traverse mount.

Shashmurin, however, would decide to add what appears to be a KV-1 mod.1939 turret on top, armed with an L-11 76.2 mm gun. The fighting compartment was moved towards the centre of the hull and morphed with the engine compartment, which was kept more or less identical to the previous KV series of tanks. His design would have been a colossal vehicle. Weighing in at 92 tonnes, it would have also been the longest KV-4 designs, at 10 meters long including the barrel.

The blueprints of the KV-4 drawn by N.F. Shashmurin. They provide extensive detail to technical specifications of the vehicle, including internal and external views.
Source. ASKM

The type of armament layout Shashmurin decided upon had a series of advantages and disadvantages over methods employed by other engineers. Firstly, the KV-1 style turret allowed for engaging armored vehicles completely independently of the 107 mm main gun. In addition, the usage of a readily available turret in combination with a simple casemate construction meant the production cost would have been significantly lower compared to that of many large KV-4 proposals. The silhouette of the tank was also lower.

Having a limited main gun traverse significantly decreased the battle value of the 107 mm gun, although horizontal traverse was kept at an acceptable range of 15° to both sides. Nonetheless, other issues were created by this weapon arrangement, such as an extra crewman and a cramped interior complicated coordination and communications. Also, the lack of the coaxial 45 mm gun meant that there was no way to range in the main gun, leading to longer target engagement times and more ‘wasted’ 107 mm shells.

Other than the superstructure and upper hull, Shashmurin kept his design simplistic in terms of the lower hull. Most components were identical and reused from the previous KV series of tanks. The idler was in the front, sprocket in the rear, and 9 road wheels on each side, sprung by torsion bars. The engine used would have been the aviation diesel 4x turbocharged M-40 V-12 1,200 hp engine, partially developed at LKZ after the original designer was arrested in 1938.

Armor was, for the most part, straightforward. The frontal facing elements were 125 mm thick, with side and rear plates also at 125 mm thick. The lower plate was bent into a rounded shape. Top and roof plates were all 40 mm, while belly plates were 50 mm up to the first 3 wheels, from after which they decreased to 40 mm. The rear was stamped in the classic KV style, with a curved cover of the cooling intake.

KV-1 turret mystery

As aforementioned, there was, seemingly, a KV-1 turret added on top of the main superstructure. Yet what model this was is a mystery. From the side, it appears to be an original turret from 1939 and 1940, with rounded edges. However, the top view brings additional details of the turret. Instead of being mostly flat, aside from the rounded edges and rear bustle, the turret bustle angled inwards sharply, resembling the turret of the T-28 and T-35A. The implementation of a L-11 gun is equally strange. As early as 1940, this gun was replaced with more powerful 76 mm guns. The pig nose gun mantlet was also kept. To the right of the gun, on the same axis, a 7.62 mm DT machine gun was mounted. Likewise, a DT machine gun was mounted at the back of the turret, in a ball mount.

In terms of armor, it is unclear if Shashmurin kept the original KV-1 turret armor values of 75 mm all around the turret. If this was the case, it would have made it more vulnerable compared to the rest of the vehicle.

Side view of the KV-1 turret. Note the clear L-11 gun with its iconic gun mount.
Source. ASKM

Top view of the KV-1 turret. The sides are not flat, but rather curve towards the rear, like on a T-28 turret. Note the coaxial DT machine gun.
Source. ASKM

Crew

The crew consisted of 7 men. The driver and radio operator were seated in two protrusions from the main casemate, with the main gun barrel between them. Study of the blueprints shows that the two would have had plenty of space all around. Further inside the casemate were the main armament’s gunner and loader. In many KV-4 designs, two loaders were dedicated to manning the ZiS-6, however, as the ammunition was placed close by and there was no coaxial armament, it required only one loader. In the KV-1 turret, another gunner and loader were seated, manning the L-11 gun. Inside the turret was the commander as well, a position which would have offered great vision. Nonetheless, commanding the tank would have been a true challenge. The commander had to prioritise and coordinate target acquisition and engagement of both guns. He was completely isolated from the driver and radio operator, who relied upon the commander for orders. Additionally, as is the case with many turretless AFV, the main gunner and driver had to have good communication and synchronisation for engaging targets. This communication was provided by a 10-R intercom.

Armaments

The main armament used was a ZiS-6 (F-42) 107 mm gun, designed by V.G. Grabin between December 1940 and early months of 1941. It had a muzzle velocity of 800 to 840 m/s. Ammunition was one-piece and weighed 18.8 kg. The breech lock was mounted vertically and was semiautomatic. It could allegedly penetrate 115 mm of armor at 1,000 m. Gun elevation was of +13° and depression of -4°, while horizontal traverse was 15° to both sides. Ammunition was stowed vertically, with circa 112 or 102 (according to Shashmurin’s blueprints) rounds stowed inside. Armament in the turret was the L-11 76 mm gun, used on the first production variants of the T-34 and KV-1. It had a muzzle velocity of 610 m/s and a shell weight of 6.5 kg. Its gun elevation was +26° and depression was -7°. Around 120 76 mm rounds were stowed horizontally in the hull. Additionally, there was a coaxial DT 7.62 machine gun and one ball-mounted in the back of the turret, with +25° and -15°. A flamethrower was also mounted in the radio operator’s location, in a ball mount, with ’20 shots”.

Unlucky Cyclops

The KV-4 program as a whole was unsuccessful. After Dukhov’s design was named as winner, work should have started on detailed blueprints, allowing for the other factories involved to start prototype production. However, by the deadline (15th June), the blueprints were not submitted. Just a week later, on 22nd June, 1941, Nazi Germany attacked the Soviet Union. Work continued at the SKB-2 design bureau, especially on the KV-5, but the KV-4 seems to have been forgotten. By August, German forces were approaching Leningrad, and SKB-2 was evacuated to ChKZ. Work on these heavy tanks would not resume.

With the KV-1 engaging in full-fledged battles, its weaknesses were immediately apparent. It suffered countless gearbox failures, was slow and bulky and crews preferred the T-34. The situation was so bad that it was threatened to be put out of production. Hearing about the gearbox disaster, which he expected, Shashmurin was furious. Kotin would adopt his design, not after a fair share of arguments, for the gearbox of the KV-1S, a very well liked development of the KV-1. Shashmurin would later head the development of the KV-13 and IS as well.

Shashmurin’s KV-4 design was even less successful. While he did receive the 5th place in the competition, none of his design features would be reapplied in the KV-5. It was indeed one of the more distinctive and unusual designs, though its combat value would have been questionable.

Final variant of Shashmurin’s KV-4. Illustration by Pavel Alexe.

KV-4 Shashmurin specifications
Dimensions (L-W-H)	10.00 (9.50 without barrel) – 4.00 – 3.85 m
Total Weight, Battle Ready	92 tonnes
Crew	7 (Commander, main Gunner, turret Gunner, Driver, Radio operator, main loader & turret loader) )
Propulsion	1,200 hp diesel V-12 M-40 with 4 turbochargers
Speed	35 km/h
Armament	107 mm ZiS-6 (F-42) main cannon (112 or 102 rounds) 76 mm F-11 secondary cannon (120 rounds) 2x 7.62 mm DT machine guns (400 rounds) Unspecified flamethrower (hull)
Armor	Front top plate: 125 mm Side plate: 125 mm Top and belly: 50 to 40 mm
Total Production	0; blueprints only

Sources

Breakthrough tank KV – Maxim Kolomiets
Supertanki Stalina IS-7 – Maxim Kolomiets
KV 163 1939-1941 – Maxim Kolomiets
Confrontation – Ibragimov Danyial Sabirovic
50 years of Confrontation – Nikolai Fedorovich Shashmurin
Soviet Warrior (magazine), 1990 – Sergey Ptichkin
Bronevoy Schit Stalina. Istoriya Sovetskogo Tanka (1937-1943) M. Svirin
About the forgotten creators of Soviet armored power. (historyntagil.ru) – S.I. Pudovkin
German Lion | Warspot.ru – Yuri Pasholok
Tank building on the verge of common sense | Warspot.ru – Yuri Pasholok
Large caliber for large HF | Yuriy Pasholok | Yandex Zen – Yuri Pasholok
In the shadow of the Leningrad grandees | Warspot.ru – Yuri Pasholok
Tank Archives: Soviet 107 mm Guns – Peter Samsonov
Tank Archives: KV-3 Mulligan – Peter Samsonov
Tank Archives: Heavy Tank Costs – Peter Samsonov
Tank Archives: ZIS-6 Characteristics – Peter Samsonov

Cold War Romanian Armor Cold War Soviet Vehicles in Foreign Service Modern Romanian Armor

4K51 Rubezh in Romanian Service

Post author By Pavel Alexe
Post date June 6, 2022
No Comments on 4K51 Rubezh in Romanian Service

Post-1989 4K51 system, painted in the 90s with a 4 tone camo-pattern, until 2010.

Socialist Republic of Romania/Romania (1987-2024)
Anti-Ship Coastal Defense Missile System – 4 Purchased

While Romania’s topography consists mainly of great plains crossed by the Carpathian mountain chain, Romania has an opening to the Black Sea stretching over 245 km. For centuries, this opening has proved crucial for the local population, offering a great trading route with nearby territories, and a connection with the Danube river. When the Romanian Communist Party started its wide scale industrialisation program in the 1960s, the opening to the Black Sea would become even more important, and would require serious defending, both via the sea, but also directly from land. The last piece of equipment purchased by the Socialist Republic of Romania for this role was the 4K51 Rubezh, a Soviet mobile coastal anti-ship missile system, that could provide cheap and fast defense against naval threats.

4K51 Rubezh launching a missile at Capu Midia in 2010.
Source: MApN via Ștefan Ciocan

Background, the P-15 Termit in Romania

The Romanian re-armament plan of the 1960s consisted of purchasing a variety of modern Soviet equipment, most notably rockets and missiles. Such weapons became exponentially more important, offering immense destruction power, with short travel times and long ranges, with relative safety for the firing vehicle. One of these systems was the P-15 anti-ship missile, initially intended for ship-to-ship use.

In March of 1961, a delegation of the Romanian military was sent to Moscow to discuss the terms of the Warsaw treaty, as well as rearmament of the Romanian military. During this period, the acquisition of 6 Project 205 (Osa-class missile boats) for the Romanian Navy was decided, to be received in the period of 1962 and 1965. These ships were equipped with 4x P-15 Termit missiles each, and formed a brand new naval battalion. The new unit would be named the 133rd Vedete (Missile boat) battalion. A total of 5 Osa-class boats were imported in 1964, with several produced locally later on, the boats receiving the designation of NPR, Navă Purtătoare de Rachete (rocket carrying ship). The P-15 would be transported on land by SR-114 Bucegi trucks. The Romanian Frigate Mărășești also uses 4 P-15 launchers, with 2 launch tubes each.

The 4K51 Rubezh missile system was purchased in 1988 brand-new from the USSR, as Romania completely lacked a designated mobile coastal defense missile system, with only conventional artillery systems and the SA-N-2 Volhov stationary missile systems, which the Romanian military claims could also be used against naval targets. Just 4 systems were purchased and were delivered by March 1988. Interesting to note is that the systems have not undergone any sort of modification, either in the Soviet Union or Romania, and thus, all writing and information inside the vehicles are in Russian, in Cyrillic writing.

SR-114 Bucegi trucks of the Naval Forces transporting P-15 Termit missiles.
Colorized by Smaragd123

4K51 missile system

In the 1960s, the Soviets were analyzing their existing coastal-defense systems, the 4K87 Sopka and the 4K44B Redut. The Sopka was already obsolete, while the Redut, despite its supersonic cruise speed and long range, had a long fire preparation time and was simply too large. Additionally, it was not allowed for export. Thus, development started at the Raduga design bureau in 1970, with the Moscow Design Bureau of Mechanical Engineering designing the missile launcher, named 3S51 with KT-161 launch containers. The Design Bureau of the Minsk Automotive plant would undertake the necessary modifications for the chassis, based on their own 8×8 MAZ-543M truck. The 23-tonne truck used a 38.8 liter V-12 D12A-525A diesel, delivering 525 hp with 38,8 l and consuming 80 liters / 100 km (2.94 miles / gallon). It had an automatic gearbox and reached a top speed of circa 60 km/h. Fuel reserve was sufficient for 630 km.

The system consisted of 4 main components. The truck itself had the driver’s cab at the front, which was small in size in order to be able to fit the engine to the right. Behind was the telescopic radar. Behind it was the main control and firing cabin, which housed the crew of 6 men and all the FCS equipment and turbocharged power supply. Lastly, the two launching pods were mounted at the back, with a full 360° range. The launching of the missiles could only be done in a 110° range adjacent to the chassis, and the lowest elevation being 20°. Two lids, on both sides of the launcher tube, were opened automatically prior to launching.

The ZC51 Harpoon telescopic radar ensured the independence of the system, not requiring an external radar, though an extra long-range radar could be used (something Romania did not order for the Rubezh). The Harpoon radar had a range of 100 km and scanned the surface of the water level over this area. In tandem with the mobile 3S51 launchers, they ensured that the system was ready to fire in just 5 minutes, and could drive off even faster.

Testing of the vehicle began in late 1974, at the 141st independent Artillery Division, for which the 1267th Independent Coastal Missile Division was formed at the Black Sea. Firing tests were held at Cape Fiolent, in Crimea. A total of 23 launches were built between 1975 and 1977. It was adopted in service with the Soviet Navy on the 22nd October, 1978, after Decree from the Council of the Ministers of the USSR No. 853-875.

In the 1980s, a modernization was made, using an enlarged MAZ-543M truck. The launching system was named 3P51M.

4K51 Rubezh prior to a missile launch at MILREX 2007 at Capu Midia, with its Harpoon radar extended and tube 2 ready for launch. Note the 4-tone camouflage pattern.
Source: Bogdan Dinu

P-15M (P-21 & P-22)

The missile used on the 4K51 was the P-15M, which was an excessively modernized variant of the P-15 missile. It featured a trapezoidal wing, which was folded during transport in the vehicle, and would lock open after launch. Its empenagge consisted of a small vertical stabilizer and two horizontal stabilizers. Its propellant consisted of a two-stage rocket engine. The first engine was used at the initial launch and to reach the designated cruise altitude. Once it ran out of fuel, the cruise engine would start operating. The fuel used was the usual solid-state TG-02, in tandem with AK-20K nitric acid based oxidiser. The cruise engine was tasked with reaching a speed of 320 m/s (1,150 km/h) and maintaining it until it reached the target. During navigation, the rocket used an APR-25 autopilot, radio-based altimeter, navigational system and homing radar. The total range was thus increased to 80 km, at maximum cruise altitude of 250 m, but between 50 and 100 m above sea-level was recommended. It had a mass of 2,573 kg, out of which 513 kg was the conventional warhead. It was 6.565 m long, a wingspan of 2.4 m and a diameter of 0.76 meters. Each launcher had 2 different target acquisition systems, one with an active radar, while the other had a thermal infrared system. These missiles were sold internationally as the P-21 and P-22 respectively. The 2 target acquisition types offered crews flexibility in regards to what missile to launch, taking into consideration the target. Alternatively, firing both missiles ensured a higher chance of a hit, especially if the enemy vessel tried to jam the systems.

Loading of a NPR with P-15M rockets. Note the folded wings.
Source: Flacăra

Organization

On 30th of November 1987, as per the General Staff, the 460th Coastal Rocket Battery was formed, part of the garrison at Mangalia. The unit received all 4 systems by March 1988. First firing exercises were held on 18th of May, 1989, at the Tuzla firing range. On 30th of July, 1990, the unit changed name into the 508th Coastal Rocket battalion, and in 2005 it was integrated into the 190th Naval Rocket battalion. Since 2017, the 585th C.B.R.N. defense company is integrated into the 508th Coastal Rocket battalion.

4K51 Rubezh in 2017, with new NATO 3-tone camouflage. Note the retracted Typhoon radar, in driving position.
Source: Unknown

Camouflage

After the original reception, these vehicles were painted in the standard dark green color and given a Romanian roundel on the door. During the 1990s, the vehicles were repainted in a 3-tone camouflage with light blue, light green and yellow over the base dark green coat, resulting in a flamboyant 4-tone camo. This was usual practice, as there was no camouflage norm set by the General Staff, so units would paint their vehicles with whatever paint was available, resulting in some interesting colors and patterns. Between 2007 and 2010, the vehicles were repainted again, this time in a 3-tone camo, with light green, yellow and brown. In 2017, with higher budgets to individual units and reorganization, the vehicles were painted to the standard NATO 3-tone camouflage with khaki, black, and brown.

Rubezh system with its radar extended and 3-tone yellow, brown, and light green camouflage.
Source: Ro Navy

Raytheon Replacement – NSM

There are rumors that, in the mid-2000s, the 4K51 and subsequent P-21 and P-22 missiles were to be taken out of service. Apparently, after a firing test, the missile destroyed the naval target on first hit, thus extending the service life of the missiles in Romania, both on the 4K51 but also for the ships that used it. Financial issues are the more probable reason behind this extension, but the Romanian Army loves its myths. After being in service with the Romanian Navy for over 30 years, the 4K51 system is showing its age. Even early in its life, the system was questioned for its relatively short range (not necessarily an issue for Romania’s moderately small coast) but, more importantly, interception of the missile and jamming of the guiding systems. Additionally, Romania’s stock of these missiles is getting smaller, to the point that firings of real rockets are not undertaken anymore.

Since 2017, the Ministry of Defense (MApN) has shown interest in replacing the 4K51 systems with the NSM, Naval Strike Missile, developed by Kongsberg Norway. A contract was signed in May 2021, worth €286 million. This consists of 4 mobile launcher systems, 1 mobile command & control center, 1 loading and transport vehicle, as well as all testing, logistical, maintenance and training aspects. The systems will be delivered in 2024.

The NSM is a light anti-ship missile, with a range of 185 km and weighing only 125 kg. It uses an infrared sensor to identify and guide itself to the target, which makes it hard to detect by radar and is classified as a ‘stealth’ missile that can be used all-weather.

Poland acquired the system in 2008, and the US adopted the system in 2018.

Missile	P-15M	NSM
Dimensions (length – wingspan)	6.565 – 2.4 m	3.96 – 1.36 m
Mass	2.573 kg	407 kg
Warhead mass	513 kg (conventional)	125 kg
Cruising Speed	320 m/s (1152 km/h) (716 mph)	240 – 326 m/s (864 – 1173 km/h)
Cruising altitude (above sea level)	Recc. 50 – 100 m (max 250 m)	Sea-skimming (< 50 m)
Range	80 km (50 miles)	185 km (115 miles)
Target acquisition and homing system	Active radar (P-21) and thermal infrared (P-22)	Infrared imager, passive sensors, GPS

Romanian 4K51 (left) and Polish NSM (right) based on a Jelcz truck at Sea Shield 21. The difference in size between the two missile launchers is very clear.
Source: MApN Facebook

Post-1989 4K51 system, painted in the 90s with a 4 tone camo-pattern, until 2010.

4K51 Rubezh in Romanian service with the 3-tone camo pattern from 2007 to 2017.

In 2017, all 4K51 systems were painted in the standard NATO 3-tone camouflage. All illustrations by Pavel Alexe.

4K51 Rubezh missile system in Romanian service specifications
Dimensions (L-W-H)	14.2 x 2.97 x 4 meters
Total Weight, Battle Ready	40+ tonnes
Crew	6
Propulsion	D12A-525A diesel V-12 525 hp 38.8 l with 80 l/100 km consumption.
Speed	60 km/h
Armament	2x P-15M (P-21 & P-22) missiles, launched from the 3S51 with KT-161 launch containers.
Armor	N/A
Total Purchasedn	4 launchers

Sources

Forțele Navale Române (navy.ro)
TiV No.5 2021
Rachetele armatei române şi criza vectorilor nucleari sovietici trimişi în Cuba (1960-1963) | Contributors – Petre Opriș
Rachete balistice sovietice în România (1961-1998) | Contributors – Petre Opriș
https://www.hotnews.ro/stiri-defense-23117440-armele-romaniei-care-sunt-rachetele-sistemele-artilerie-din-arsenalul-militarilor-romani.htm – Victor Cozmei
OFICIAL Armata cumpără sisteme mobile cu rachete anti-navă NSM din SUA. Când vor fi livrate primele sisteme care vor păzi coasta Mării Negre – HotNews.ro – Victor Cozmei
Dotări noi la Forţele Navale Române. Rachetiştii se inst (cugetliber.ro) – Andreea Perhaiță
NSM – Naval Strike Missile – Missile Systems – KONGSBERG – Kongsberg Defence & Aerospace

WW2 Soviet KV-4

KV-4 (Object 224) Dukhov

The KV-4 as designed by N. L. Dukhov. Illustration by Pavel Alexe.

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

Tank design in the 1930s Soviet Union was a period of great experimentation and versatility, with designs ranging from jumping and flying tanks to super heavy multi-turreted ones. Yet as the Soviet tank industry matured, tank designs became more sensible and, by the late 1930s, some very promising vehicles were in development, such as the T-34 and KV-1. Nevertheless, with tensions rising in Europe after the German invasion of Czechoslovakia, Poland, and then France through the Benelux, Soviet engineers had to fall back to some older drastic ideas. One of these was the KV-4, one of the most curious heavy tank programs in Soviet tank history, as it involved a competition between dozens of designers.

Development

KV-4 designs

Placement	Name	Mass (t)	Dimensions (m) (LxWxH)	Armament	Crew	Top speed (theoretical)	Armor	Reward /Rubles
1	Dukhov KV-4	82.5	8.150 3.790 3.153	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DT machine guns	6	40 km/h	Front top plate: 135 mm Front bottom plate: 130 mm Side plate: 125 mm Top and belly: 40 mm	5000
2	Kuzmin, Tarotko, Tarapatin KV-4	88	9.26 3.78 3.175	107 mm ZiS-6 45 mm K-20 2x 7.62 mm DS-39 machine guns	6	36 km/h	Front: 125 mm Side: 125-100 mm Top and belly: 40 mm	3000
3	Tseits KV-4	90	8.85 4.03 3.62	107 mm ZiS-6 2x 7.62 mm DS-39 machine guns Unspecified flamethrower	7	45 km/h	Front hul upper plate: 50 mm Front hull bottom plate: 125 mm Turret:130 mm Side plate: 125 mm Top and belly: 50 mm	2800
4	Sychev KV-4	95 – 100	9.23 4.00 3.40	107 mm ZiS-6 (F-42) 45 mm 20-K 2x 7.62 mm DT machine guns	6	40 – 45	Turret: 135-125 mm Hull: 105 mm Top and belly: 40 mm	2000
4	Ermolaev KV-4	90	8.22 4.00 3.25	107 mm ZiS-6	6	35	130 mm
4	Ermolaev KV-4	95	8.52 4.00 3.25	107 mm ZiS-6 45 mm 20-K	6	35	130 mm	2000
5	Shashmurin KV-4	92	9.50 4.00 3.85	107 mm ZiS-6 (F-42) main cannon (112 or 102 rounds) 76 mm F-11 secondary cannon (120 rounds) 2x 7.62 mm DT machine guns (400 rounds) Unspecified flamethrower (hull)	7	35 km/h	Front top plate: 125 mm Side plate: 125 mm Top and belly: 50 to 40 mm	1500
6	Buganov KV-4	93	7.70 3.80 3.90	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front 125 mm	1000
6	Moskvin KV-4	101	9.573 4.03 3.74	107 mm ZiS-6 45 mm 20-K	6	40 km/h	Front 130 mm	1000
7	Pereverzev KV-4	100	9.5 3.8 3.82	107 mm ZiS-6 45 mm 20-K 2x 7.62 mm DT machine guns	6	39 km/h	Front: 125 mm	500
7	Bykov KV-4	98.6	9.5 4.03 3.65	107 mm ZiS-6 45 mm 20-K 7.62 mm DS-39 machine gun	8	36 km/h	Front 130 mm	500
7	Kalivod KV-4							500
N/A	Fedorenko KV-4	98.65	8.10 4.03 3.70	107 mm ZiS-6 45 mm M.1938 3x 7.62 mm DT machine guns Unspecified flamethrower	6	35 km/h	Front upper plate: 140 mm Side plate: 125 mm Turret: 125 mm Top and belly: 50 to 40 mm
N/A	Kreslavsky KV-4	92.6	9 4 3.225	107 mm ZiS-6 45 mm Mod.1937 20-K coaxial 3x 7.62 mm DT machine guns	6	45 km/h	Turret: 130 mm Front hull plate: 130 mm Front upper plate: 80 mm Side plate: 125 mm Rear plate: 130 mm Top /bottom: 50 -40 mm
N/A	Kruchenykh KV-4	107.7	9.13 4.03 3.78	107 mm ZiS-6 45 mm 20-K 4x 7.62 mm DT machine guns	9	30 km/h	Front: 130 mm
N/A	Mikhailov KV-4	86.5	9 3.6 3	107 mm ZiS-6 (F-42) 45 mm Mod.1937 20-K (hull-mounted) 3x 7.62 mm DT machine guns	6	50 km/h	Turret: 130 mm Hull: 130 mm Belly and belly: 50 – 40 mm
N/A	Marishkin KV-4	86.4	8.7 3.6 3.5	107 mm ZiS-6 45 mm 20-K	7	40 km/h	Front: 130 mm Upper frontal: 80 mm
N/A	Pavlov & Grigorev KV-4	91	8.5 4.0 3.6	107 mm ZiS-6 45 mm 20-K	6	45 km/h	Front: 100 – 125 mm
N/A	Turchaninov KV-4	89.5	9.8 4.0 3.0	107 mm ZiS-6 45 mm 20-K DT machine gun	7	35 km/h	Front: 125 mm
N/A	Strukov KV-4	92	8.6 4.0 3.8	107 mm ZiS-6 45 mm 20-K	6	50 km/h	Front: 80 – 130 mm
N/A	Unknown KV-4
N/A	Unknown KV-4

On 11th March, 1941, the GABTU (Main Directorate of Armoured Forces) was informed by the Soviet Intelligence services of the existence of new German heavy tank projects. The report, naturally, was a mixed bag of real information and rumours. It is important to note that, while the Soviet Union and Nazi Germany were more or less allies during this period, tensions were high and any sort of technological advancement of the opposition had to be met with a proportional (or, in this case, disproportional) response.

The document received was titled “The direction of development of the German armed forces and changes in their state” and discussed several tank projects. When it came to heavy tanks, a chart presenting 3 tank models was shown:

Mark V (36 tonnes, 75 mm gun, 2x machine guns, ≤ 60 mm of armor)
Mark VI (45 tonnes, 75 mm gun, 20 mm gun, 3x machine guns, ≤ 70 mm of armor)
Mark VII (90 tonnes, 105 mm gun, 2x 20 mm gun, 4x machine guns, unknown armor)

The report also mentioned, based on unconfirmed information, 72 tonne French tanks (possibly the Char 2C, which weighed 69 tonnes) present at the occupied Renault factory, in addition to 60 and 80 tonne tanks being built at Škoda and Krupp.

On the one hand, the Germans had indeed begun development of several heavy tanks, such as the 30-and 36-tonne projects (VK30.01(H) and VK36.01(H)). A month after the original Soviet report, in May, the Germans decided that, for 1942, the armor of future heavy tanks had to be improved. This would consist of 100 mm of frontal armor and 60 mm at the side. In terms of heavier vehicles, the VK65.01 appeared in January 1939.

Interestingly, the Pz. Kpfw. VII, commonly known as the Löwe, with its many variants and stages, would not appear until November of 1941, with development starting in December. Mentions of a tank armed with a 15 cm L/40 existed earlier on. This begs the question on what the Soviet report was based on. It was very likely a combination of several tank designs and proposals, alongside rumours and speculations, likely cherry picked to sound as alarming as possible.

To put things into perspective, during this period, the best heavy tank in Soviet service was the KV-1, armed with the 76 mm L-11, meant as a stopgap until the introduction of the F-32 gun, which was not a significant improvement anyway. These guns were seen as problematic, especially by armament designer V.G. Grabin, but the political rush to push the KV-1 into production and military service left it with considerable faults and problems, including the armament and the infamous gearbox, which, it must be noted, was designed by N.L. Dukhov himself. The most important aspect of the KV-1 was its armor, with 90 mm at the front of the turret and 75 mm at the front of the hull. By 1941, the Soviets had several improvements of the KV-1 in the works, including the T-150 and KV-220, which brought more armor and better armament. With hindsight, the KV-220, with its 85 mm F-30 gun and 100 mm of armor all around, would have been (on paper) on par with the German Tiger I, which entered production only in August of 1942, 1.5 years later. It seems it would have been rather reliable, running 967 km with the V-5 700 hp engine (only needing 2 idlers, a torsion bar, 6 idler axles replaced and shearing 2 teeth in the transmission and destroying the eyelet of the clutch) after the 2 V-2N supercharged experimental engines broke.

Nonetheless, the Soviet authorities did not take the report lightly and immediately ordered work on an even heavier tank. It was expected that the gun used would be the 105 mm Flak 39. The Soviets had previously purchased this gun in 1940 for testing and, after firing trials, it was noted that a tank required 130 mm of armor or more to withstand fire from it. The Kirov Leningrad plant’s SKB-2 design bureau was tasked with the design of the new tank. At the same time, they were working on the KV-3, at the time a 50-tonne heavy tank, already superior to any German tank at the time. The Kirov plant had also worked on the T-150 and KV-220 tanks, which were further developments of the KV-1.

Technical requirements

Design and technical requirements were given only 10 days after the initial report, on 21st March, 1941. The new super heavy tank was named KV-4 (the acronym KV stands for Kliment Voroshilov, People’s Commissar for Defense of the Soviet Union until 1940) and received the GABTU designation Object 224. It was to weigh around 70 to 72 tonnes, with a frontal armor of 130 mm, side armor of 120 mm, and 40 mm on the belly and top. The main armament was to consist of the ZiS-6 F-42 107 mm gun. It was meant to have a full traverse range of 360° (though a handful of designs would mount the gun in a casemate with limited traverse). Elevation was to be between 15° to 17° and depression between -2° and -3°. Secondary armament would consist of a 45 mm gun (model 1937 or 1938) and 3 DT machine guns; one coaxial, one in the turret bustle and one at the front of the hull. Mounting of a 76 mm ZiS-5 gun was also desired as an alternative to the ZiS-6, though this was eventually dropped. A flamethrower was also mentioned for protection against approaching infantry.

The powerplant was meant to be a 1,200 hp engine, with the tank reaching an estimated top speed of 35 km/h. However, since there were no such powerful engines available at the moment, the 850 hp V-2SN was to be used as a temporary fix. For the KV-5 (and potentially the KV-4 as well), mounting 2 V-2SN was also considered until the M-40s were ready. Eventually, LKZ managed to produce 58 M-40 engines by August. Another variant was considered, the M-50, giving out 1,000 hp, which was meant for torpedo boats. The fuel was meant to last for 10 hours of continuous driving, in conditions between -40° and 40° Celsius. The gearbox had to be an automatic planetary type and the brakes had to hold up the tank’s weight on a 45° slope angle. The crew was to be composed of 6 men: Commander, gunner, loader, turret mechanic (loader assistant), driver, and radio operator, with the last two in the hull.

On 27th March, the Council of Ministers of the USSR released the plans for the development of the heavy tanks, presenting the deadlines of the development process. The LKZ plant was to provide drawings by 17th July, Plant No. 92 to deliver a 107 mm ZiS-6 and 76 mm ZiS-5 by 1st September and Izhora plant in Leningrad to build the hull and turret by 1st October. In terms of powerplants, the V-2SN and M-40 engines were considered. From a letter dated 30th May, the development (from blueprints to prototype testing and improvement) of the KV-4 was expected to cost 3,100,000 Roubles, while the KV-5 was estimated at 3,600,000 Roubles. Just the construction and factory trials of the KV-4 were estimated at around 1,800,000 Roubles. To put this into perspective, the production of a single KV-1 was around 295,000 Roubles (May 1942).

In an interesting turn of events, by 7th April the plans were changed entirely. The KV-3 program was revitalized, with the weight increased to 68 tonnes, armor increased to 120 mm and mounting a 107 mm gun. Consequently, in a letter to LKZ factory director I.M. Zaltsman, the KV-4 requirements were increased to a weight of 75 tonnes, 135 mm (some sources claim as much as 140 to 150 mm) of armor on frontal areas, and 125 mm on the sides and rear. The deadline for the blueprints was brought forward to 15th June. The hull and turret were expected on 15th August. Simultaneously, the KV-5 was brought to life. It was to be a response to the so-called ‘Pz.Kpfw.VII’, with a mass of 90 tonnes, frontal armor 170 mm thick, and 150 mm thick on the sides. It was to be built by 10th November.

The turrets had to be of welded and stamped construction, as castings at these thicknesses were not technologically possible at the time. Another issue with the armor was the connection. The Soviet armor industry could barely handle welding 75 mm armor plates, let alone anything above 125 mm. This issue was partially solved on the KV-5 (which got further into its developmental stage), where steel rods would be pushed and welded in holes drilled through the two armored plates, which in turn would be laid onto one another.

The main gun required between 70 and 80 rounds of ammunition. To top it all off, in a letter from the chief or the Main Auto and Armour Directorate of the Armoured Forces to the LKZ and Izhor factories, the prototypes of KV-4 (and KV-5) were expected to be completed and enter the testing phase by 1942.

Connecting pins for the large steel plates. This system was used on the KV-5, and likely on the KV-4 as well. The German Maus used them as well. Note, however, that the Soviet counterparts did not use interlocking plates, but rather L-shaped connections.
Source: Andrew Hills

Drawing competition

Work began on the KV-4 at Kirov on 10th April. The head designer was J. Y. Kotin. Considering that the tanks were to be designed from scratch, Kotin decided upon doing a competition. After getting Zaltsman onboard, they decided to even give prizes for the best designs. Most of the engineers at the Kirov SKB-2 design bureau would participate in the competition. No details were given about the layout, prompting a variety of unique and creative designs. However, a bit of confusion seems to have risen regarding specific details, as the specifications set up at LKZ did not entirely match the ones requested by the GABTU. The mass was set between 80 and 100 tonnes, armament consisting of the ZiS-6 107 mm and a 45 mm gun mod.1937, with the second gun meant for zeroing in the main gun and for dealing with softer targets. The Soviet military allegedly requested a flamethrower as well, but some designs lack it.

By 9th May, the competition was over and the winners were announced by I.M. Saltzman. In total, 27 different designs were submitted (excluding different variations of the same design). In first place came N.L. Dukhov, who received 5,000 Roubles. Second place was given to a design made by 3 engineers, K.I. Kuzmin, P.S. Tarapatin, and V. I. Tarotko, who received 3,000 Roubles to be split between them. On third place came N.V. Zeits, who received 2,800 Roubles. The list continues to the 7th spot, with many places having several designs. Unfortunately, some designs have been lost to time, and some designs have unknown authors, or some lost drawings. From the 11 ‘winning’ designs, only Kalivoda’s project is missing blueprints. Kotin himself received 3,100 Rubles for leading the engineering team. To put these sums in perspective, a soldier would be awarded 500 rubles for destroying an enemy tank on the front.

Designer name	Place	Prize received (Rubles)
N.L. Dukhov	1	5,000
K.I. Kuzmin, P.S. Tarapanin and V. I. Tarotko	2	3,000
N.V. Tseits	3	2,800 (2,000 according to another archive document)
L.E. Sychev	4	2,000
A.S. Ermolaev	4	2,000
N.F. Shashmurin	5	1,500
K.I. Buganov	6	1,000
G.N. Moskvin	6	1,000
L.N. Pereverzev	7	500
V. Bykov	7	500
Kalivoda	7	500

Other engineers who presented designs but did not receive any awards were F.A. Marishkin, S.V. Federenko, M.I. Kreslavsky, V. Pavlov and D. Grigorev, P. Mikhailov, G. Turchaninov, N. Strukov, and 2 other unnamed designers.

Despite the exciting competition, the progress was slow. By 12th June, 3 days prior to the deadline, Marshal of the Soviet Union G.I. Kulik sent a letter to LKZ demanding the speed-up of the design process. Yet the drawings were never submitted. Just 10 days later, on 22nd June 1941, German forces began their invasion of the Soviet Union.

The GABTU decided that the KV-3, which was in an advanced stage, would continue development and be implemented as a stopgap measure until the KV-4 and KV-5 were ready. These two would be tested against each other and the winner would be produced. Development of the KV-5 continued until August, albeit at a much slower rate, when the Germans had already reached Leningrad. The workers and engineers at LKZ, including SKB-2, were moved to ChKZ in Chelyabinsk.

N. L. Dukhov

The winner of the KV-4 competition, Nikolai Leonidovich Dukhov, was born in 1904 in Veprik, in modern day Ukraine. He was behind several Soviet tank projects. In his first years as an engineer, he worked at the Putilovets tractor factory, on the Universal tractor. In 1936, he worked on his first tank project, a modernization of the T-28. A few years later, his team at the LKZ (Kirov) SKB-2 design bureau was responsible for designing the KV-1 heavy tank. After the Siege of Leningrad, SKB-2 was moved to ChKZ, from where he continued designing tanks. Other noteworthy tanks designed under his leadership were the KV-1S, KV-2, KV-85, KV-13, IS, IS-2, IS-3, and IS-4.

After 1948, he was involved in the Soviet nuclear program, being deputy chief designer at KB-11 (since 1992 known as the ‘Russian Federal Nuclear Center’) and participated in the development and testing of the RDS-6s thermonuclear hydrogen bomb, with a yield between 400 to 500 kt. In 1954, he became chief director and supervisor at branch No.1 of KB-11, which still bears his name to this day. He led it until his death in 1964, at just 59 years. He received 3 Hero of Socialist Labour medals, 4 Lenin Orders, 5 Stalin Prizes, the Lenin Prize, the Order of Suvorov, the Order of the Red Banner of Labour, the Order of the Red Star, the medal for Labour Valour, the Medal For the Victory over Germany in the Great Patriotic War 1941–1945, the Medal for Valiant Labour in the Great Patriotic War 1941–1945, the Jubilee Medal 30 Years of the Soviet Army and Navy, and the Jubilee Medal 40 Years of the Armed Forces of the USSR.

Nikolai Leonidovich Dukhov, one of the most important Soviet tank designers of the Second World War, in charge of designing some of the most iconic Soviet tanks, like the KV-1.
Source: Wikipedia.ru

Dukhov’s design

Dukhov presented at least 4 drawings of his proposal, one side view of the entire tank, one cutout top view of the turret, one partial cutout of the hull and one showing the automated round lifting system. The design was very similar to the KV-220, a tank designed with L.E. Sychev and B.P. Pavlov (both of whom submitted KV-4 designs), but much larger. The hull was essentially an up-armored and lengthened KV-1 hull, with 8 wheels per side, sprung by torsion bars. Other details and components remained mostly identical to those of previous prototypes and of the KV-1 mod.1941. The exact number of return rollers is unknown, but comparing to previous designs, 4 appears most likely. Curiously, the rear engine deck plate was angled downwards, similar to the KV-1S. His design was the lightest of all KV-4 designs, estimated at ‘just’ 82.5 tonnes.

The single KV-220 prototype, armed with an 85 mm F-30 gun. It served as a basis for the KV-3 tank, and as a great inspiration for Dukhov and his KV-4 drawings.
Source: Tank Archives, colorized by Smargd123

The main engine considered was the M-40 aviation engine, developed at LKZ (after the original designer, A.D. Charomsky, was arrested in 1938, during the Purges). It had an output of 1,000 horsepower (later improved to 1,200) with 12 cylinders arranged in a V-shape, and 4 TK-88 turbochargers. Displacement was of 91.07 liters. Since it was based on an aviation engine, it could run on both diesel and kerosene, allegedly even gasoline. With such a powerplant, Dukhov expected his design to reach an optimistic 40 km/ top speed. There was also an upgraded version, the M-40F, delivering up to 1,500 hp. The other engine considered was the V-2SN, which was an upgraded variant of the classic V-2 12 cylinder engine. It was boosted with a turbocharger to 850 hp.

Side cutout view of Dukhov’s KV-4. The similarities to the KV-220 are very clear.
Source: ASKM

The turret designed by Dukhov was also similar to the KV-220, with the main difference being that the frontal plate (mostly covered by the mantlet) was angled, as opposed to flat like on previous KV tanks. A total of 4 plates were used for the turret, with the frontal plate angled at circa 20° and 130 mm thick. The side armor plate would have been circa 125 mm thick and stamped into shape. The rear plate was flat and 125 mm thick. On top of the main turret, a smaller turret was added armed with a DT machine gun. This turret had circa 3 vision periscopes for the commander. Another 4 periscopes were scattered around the turret to give vision to the rest of the crew members.

Top view of the turret, with view of the two guns and turret floor.
Source. ASKM

In terms of placement of the 6 crewmen, the driver and radioman were placed in the hull, in identical positions to other KV series tanks. The gunner was seated to the right of the 107 mm gun, while the commander was standing behind him, operating the cupola. As for the loaders, one was seated to the right of the 45 mm gun and was tasked with loading it and lifting ammunition for the 107 mm. The other loader was standing behind the main gun and had the task of loading the main gun. They used a 10-R intercom for communication between each other.

Top view of Dukhov’s hull, the front of the hull has been cut out. The ammunition loading system can be seen, using special components holding the shells by the ends.
Source: ASKM

Armament

The KV-4 used the F-42 ZiS-6 107 mm as the main gun. It was designed by the iconic V.G. Grabin at factory No.92. First appearing in documentation in December 1940 as the F-42, but renamed to ZiS-6 in March 1941. The gun was ready by 14th May, taking only 38 days to design according to Grabin himself, after both Marshal of the Soviet Union Kulik and Stalin spoke to Grabin about the issue, though a phonecall between Grabin and Stalin revealed that the gun had to be designed in 45 days. Plant No-92 was forced to work ahead of schedule, and on 27th May, sent a gun to LKZ for mounting on the KV-2 for testing. Yet the Izhora plant, tasked with making the turret for the test ring, using a KV-3 gun mount, was progressing very slowly. On 18 June, Marshal Kulik had to intervene (again), for the Izhora plant to finish the turret. Testing finally began on 25th June and ended on 5th July. After the initial test, faults were fixed, and the gun was deemed ready for production. Serial production began at the New Sormovo plant in July. But, according to Grabin’s memoirs, the lack of cooperation and work from the tank factories was a large dissapointment.

The production of the ZiS-6 increased daily. But there was still no sign of the tank for which the gun was intended. Even after the beginning of the war, the Kirov plant did not deliver a single tank. The lack of the new tank forced us to limit production and eventually, cancel it. It is difficult and embarrassing to write about this, in those days when everything that could shoot, even museum pieces, were sent to the front, around 800 gun barrels had to be sent back to the melting furnace

– V.A. Grabin, extract from his memoirs.

In September, the ZiS-6A was discussed for the KV-4, which involved the mounting of a 45 mm gun coaxially, but it remained just an idea, mostly because of the abandonment of the KV-4.

The KV-2 fitted with an 107 mm ZiS-6 and the KV-3 gun mantlet in June 1941.
Source: Thinky via WT forums

In terms of technical data, the ZiS-6 had an muzzle velocity of 800 to 840 m/s. Ammunition was one-piece and weighed 18.8 kg. The breech lock was mounted vertically and was semiautomatic. It could allegedly penetrate 115 mm of armor at 1,000 m.

Regarding secondary armament, Dukhov fitted his design with a coaxial 45 mm mod.1937. With a muzzle velocity of 750 m/s, it would be used for ranging in the main gun, while also engaging targets that would not require the main 107 mm gun. Loading would be done by any of the two loaders. There was no firing mechanism designed for it, but it was likely fired independently from the main gun by the gunner. The tank also had at least two DT machine guns, one mounted in a ball mount in the hull, and the other in the secondary turret on the top of the main turret. Ammunition for it was stowed in the hull, on both sides of the turret ring.

Dukhov had envisioned 2 ways to load the main gun. The first was the classic way, by simply lifting the ammunition stored in the floor of the tank’s hull. There must have been a form of turret floor, as the entire hull floor was peppered with ammunition. This was in no way a simple endeavour, but with two loaders, it was a realistic task. The second option was a semiautomatic loader system, which had a system that would lift up the shells from the hull to the same level to the gun breech, from where the loader could load them in. The shells would be lifted by a chain-like system, in-line with the gun breech. These would be stored across the hull, and would have been required to be placed manually in the lifting system.

View of the loading layout and system proposed by N.L. Dukhov for his KV-4.
Source: ASKM

German invasion

Even after the German attack on the Soviet Union, work on tanks continued at LKZ. For the KV-5, the engineers who had received the top places in the KV-4 competition (except the 3 in second place) would work together on the KV-5. This gained traction and blueprints were being drawn, including the turret, hull and running gear components. As for the KV-4, there was barely any progress. Dukhov’s design was awarded as the best, but what this truly meant for the KV-4 is all speculation. Whether Dukhov’s would have been the main layout of the final KV-4 prototype is unknown. Work continued on the KV-5 and KV-3 until August, by which time the Germans were quickly approaching Leningrad. To deal with this, the SKB-2 design bureau was evacuated to ChKZ in Chelyabinsk. There, work on the KV-4 and KV-5 would not resume, as they were seen as a large waste of time and money when the Soviet Union needed tanks yesterday.

With the KV-1 seeing combat against the Germans, it was truly confirmed how unprepared for service it truly was. Dozens of reports came in about transmission and gearbox failures, the vehicle being too heavy and slow, and crews preferring the T-34. The situation got so serious that Stalin himself said that, if the issues would not be fixed, the KV production would be discontinued. This obviously came as a serious blow to LKZ engineers, which immediately began improving the KV.

Additionally, the conspired German heavy tanks never came. Thus, all unnecessary heavy KV projects were left behind and work was focused on improving the KV-1. The work eventually resulted in the heavily praised KV-1S, experimental KV-13 and, finally, the iconic IS.

The KV-4 designed by Dukhov, as represented in the MMO World of Tanks by Wargaming.net.
Source: Wargaming.ne

Conclusion

Arguably one of the most interesting Soviet heavy tanks of the Second World War, the KV-4 was not just a massive vehicle, but also involved the interesting competition tactic which would not be applied again by Soviet designers. This brought a variety of interesting and unique ideas. However, no matter how advanced or revolutionary the KV-4 designs were, the entire program was simply too expensive and worthless, especially once the Soviets had entered war against the Axis. The program was not without its merits.

Dukhov’s KV-4 incorporated an efficient and trialed design into what was seen as the most successful KV-4 variant. It was the lightest, simplest, and almost a natural evolution from the KV-220. Equally interesting, he envisioned a partially automated loading system, with shells being lifted to the level of the gun breech. This gave him the victory against all the other engineers, but it was to no avail.

The KV-4 as designed by N. L. Dukhov. Illustration by Pavel Alexe.

KV-4 Dukhov’s variant specifications
Dimensions (L-W-H)	8.150 – 3.790 – 3.153 m
Total Weight, Battle Ready	82.5 tonnes
Crew	6 (Commander, Gunner, Driver, Radio operator, loader & turret mechanic/loader assistant)
Propulsion	1,200 hp diesel V-12 M-40 with 4 turbochargers
Speed	40 km/h (hypothetical)
Suspension	Torsion bar, 8 wheels per side
Armament	107 mm ZiS-6 (F-42) 45 mm Mod.1937 coaxial 2x 7.62 mm DT machine guns
Armor	Front top plate: 135 mm Front bottom plate: 130 mm Side plate: 125 mm Top and belly: 40 mm
Total Production	0; blueprints only

Sources

Breakthrough tank KV – Maxim Kolomiets
Supertanki Stalina IS-7 – Maxim Kolomiets
KV 163 1939-1941 – Maxim Kolomiets
Confrontation – Ibragimov Danyial Sabirovich
Bronevoy Schit Stalina. Istoriya Sovetskogo Tanka (1937-1943) M. Svirin
About the forgotten creators of Soviet armored power. (historyntagil.ru) – S.I. Pudovkin
German Lion | Warspot.ru – Yuri Pasholok
– Yuri Pasholok
Tank building on the verge of common sense | Warspot.ru – Yuri Pasholok
Large caliber for large HF | Yuriy Pasholok | Yandex Zen – Yuri Pasholok
Tank Archives: Soviet 107 mm Guns – Peter Samsonov
Tank Archives: KV-3 Mulligan – Peter Samsonov
Tank Archives: Heavy Tank Costs – Peter Samsonov
Tank Archives: ZIS-6 Characteristics – Peter Samsonov

Cold War Soviet Prototypes

7.5 cm SPG (Soviet Hetzer Starr)

Post author By Pavel Alexe
Post date May 2, 2022
7 Comments on 7.5 cm SPG (Soviet Hetzer Starr)

Soviet copy of the German Hetzer Starr. Illustration by Pavel Alexe.

Soviet Union (1945-1946)
Self-Propelled Gun – Partial Blueprints Only

Bridging the seemingly non-existing gap between fiction and reality are the post-war Soviet experiments on the German Hetzer Starr technology. The German use of a rigidly mounted gun in an AFV, without any recoil absorption systems, interested the Soviets so much that German engineers that worked on the project were brought in. Studies were made, with blueprints of an AFV hull nearly identical to that of the German Jagdpanzer 38(t) Starr. To what extent these studies went, and if a vehicle was truly intended for testing, is unknown.

Origins

The German Jagdpanzer 38(t), usually referred to and more famously known as the ‘Hetzer’, has become an icon of the latter part of the German armored fighting vehicle arsenal during the Second World War. Its combat record and value impressed many, so much so that production continued post-war in Czechoslovakia as the G-13. It used well sloped armor on all sides, allowing for good protection despite the thin armor plates. The 7.5 cm Panzerjägerkanone 39 L/48 proved to be well suited for a variety of duties.

Truth is that the concept was not entirely new. The Romanians had experimented with the concept of angled walls prior to the Jagdpanzer 38(t), in their Mareşal program. On the other hand, the Soviets began as early as 1940 to work on a very cheap, light self-propelled gun which would use angled plates for better protection. Throughout the war, many variants were drawn up, built and tested, but none ever saw service. They usually tend to be simply called Russian Hetzer(s), a post war designation probably originating from Russian author Mikhail Svirin.

The last of these projects began in late 1945 and sought to offer the Soviet army an extremely cheap vehicle. It used the widely available parts from various obsolete vehicles, of which thousands were leftover after the war effort. The project was inspired from the Hetzer Starr variant, a late war production variant of which less than 20 were built. For this, German designers were brought in.

Hetzer Starr out of the December 1944 – April 1945 production batch at Skoda factory.Source: Topwar.ru

Jagdpanzer 38(t) Starr

The Jagdpanzer 38t Starr, the basis for the Soviet project, began life almost as soon as the first production versions rolled out. The word ‘starr’ is German for rigid or reinforced. The main theory behind it was to simplify production and lower the weight. Two critical points were explored, namely attaching the gun mount to the hull floor instead of the front plate roof and removing the recoil systems. Other features of the upgrade included replacing the infamous saukopf (English: pigs snout) mantlet with a more angled, bullet-shaped one, and the replacement of the engine, which in turn required a new engine deck and exhaust system.

Changing the gun mount would lower the overall weight of the vehicle, and improve production cost and speed. Another advantage of the system was more internal space for the crew, thanks to the removal of recoil equipment. Both Alkett and Rheinmetall-Borsig had made various gun mounts and trials on the idea, with several outcomes, including a 10.5 cm gun mount.

Yet the entire project proved problematic throughout the development process, as the high recoil shock and stress created gaps, cracks and loosening in the different gun and hull components. These issues were more or less fixed by the end of the war, but how reliable this technology would be in an active fighting vehicle remained an unanswered question.

A production batch of 10 vehicles was ordered in December 1944 and ended in April 1945. Yet only 2 of these vehicles left the Milovice training center.

The gun mount of the Jagdpanzer 38(t) Starr. Note how it is mounted to the hull floor and the new, more streamlined gun barrel.Source: Panzerfahrer

Development

After the end of the Second World War, the Soviets were able to capture and analyze the Starr, and were impressed by its use of a fixed mount for the gun. Thus, in November 1945, German engineers that worked on the Starr project were brought to the USSR to continue the project for the Soviet military. Studies continued into summer of 1946. As per Russian author Mikhail Svirin, one study was made for the production of a Soviet variant, more or less identical to the original German AFV. The project was commissioned by M.N. Shukin, chief designer at OKB-38.

Previous light Soviet tank destroyer projects were made at the Gorkovsky automobile plant (today known as Nizhny Novgorod), with some ‘Hetzer like’ projects as early as 1942. Work continued throughout the war, with the most advanced being the GAZ-75, also named the SU-85 (not to be confused with the T-34 based SU-85), an 18-tonne tank with 82 mm of frontal armor and an 85 mm D-5S-85 gun. It was designed in just 26 days, with I.V. Gavlov as lead designer. Despite the promising work head engineer of the GAZ factory, A. A. Lipgard canceled all AFV developments at his factory. This was not done as an act of sabotage, but rather because he wanted to prepare the factory for peacetime, when an automobile plant would not need to build tanks. By March 1944, the GAZ-75 (SU-85) was dead.

The GAZ-75 (SU-85), the apex of wartime Soviet light tank destroyers. It was armed with a 85 mm gun and 82 mm of frontal armor. Source: Yandex.ru, colorized by Smaragd123

After the great efforts of the Great Patriotic War, the Soviets found themselves with a large amount of equipment from obsolete light tanks, such as the T-30, T-40, T-60, T-70, and T-80. In a letter from the 10th of April, 1945, Deputy Commander of the Armored and Mechanized Forces, Colonel General of the Tank Forces Korobkov stated:

These vehicles are obsolete, as they have weak armament and insufficient armor. They cannot be used in battle and are only used in training units.
It would take a considerable expense to restore these tanks. Repair units are loaded with repairs of modern tanks, and it is not reasonable to distract them with repairs of obsolete vehicles.
I ask for your permission to use the aforementioned tanks until they require refurbishment, after which they will be written off and disassembled for parts. These parts will be used for light and medium repairs of tanks that are still being used.
These parts proved to be useful for many post-war AFV developments, with certain factories, like OKB IC SV in Moscow, were notorious for using components from these obsolete light tanks. Thus, there is no surprise that, when developing a light and very cheap light self-propelled gun, their components were to be used.

Where exactly the German-Soviet Hetzer Starr design was made is unknown. Equally uncertain is how far the project went. It could have simply been a technology transfer to simply test the viability of a rigidly mounted gun in an AFV. Or, as M. Svirin suggests, it went as far as an SPG designed for the Soviet army. There is not much to back this claim up other than a set of blueprints which lack any sort of automotive components.

Design

Soviet-German efforts largely reproduced the ‘Hetzer Starr’. Drawings of the hull of the project and its gun are almost identical to those of the original German blueprints. Yet some design elements were changed, for example having a single armored side plate instead of two. The drawings do not give a name to the project, and are simply labeled as 7.5 cm KwK self-propelled gun, signed by Captain Dernov. The point was to create a simple and cheap vehicle, in part to replace obsolete light tanks and SPGs. The gun was mounted to the floor of the tank, and able to pivot towards the sides an unknown amount. The crew consisted of 4 men, a commander, gunner, loader, and driver. The crew compartment and the engine were separated by a firewall. Ammunition was probably stowed along the angled side walls.

The studies made by the German and Soviet Engineers. Note that they are almost identical to the Jagdpanzer 38(t), with some exceptions, such as the single side armor plate.Source: M. Svirin via Topwar

The armament was of German origin, likely a 7.5 cm PaK 39/1 (L/48). Even the roof periscope was a typical German design, firmly attached to the gun and traversing via a cutout in the roof, covered by an armored plate. The system had a gun elevation of 15° and -8° of depression.

7.5cm Panzerjägerkanone 39 L/48 anti-tank gun armor penetration
(The data was obtained on a firing range. The armor plate was laid back at a 30-degree angle)
	Pzgr.Patr. 39	Pzgr.Patr. 40	Gr. Patr. 38 HL
Shell Weight	6.8 kg	4.1 kg	5 kg
Initial velocity	750 m/s	930 m/s	450 m/s
Range
100 m	106 mm	143 mm	100 mm
500 m	96 mm	120 mm	100 mm
1000 m	85 mm	97 mm	100 mm
1500 m	74 mm	77 mm	100 mm
2000 m	64 mm		100 mm
(Source: Spielberger, Jentz and Doyle)

Armor would have been the same as on the German Jagdpanzer 38(t), with 60 mm at the front, sloped at 30°. The side and rear armor was 20 mm.

German drawings showing the armor thickness and angles of the Jagdpanzer 38(t).Source: User Wotichen via WT Forums

Components not drawn in were likely meant to be of Soviet origin, tying in with the aforementioned obsolete light tanks and GAZ experience with designing such light tanks. Propulsion could have been dual GAZ-202 70 hp engines, for a total of 140 hp, or dual GAZ-80 85 hp engines. Considering the similarities with the German Hetzer Starr, the total weight would have been between 15 and 16 tonnes. A hypothetical speed of 40 km/h could have been reached. No details are yet available on the running gear. If already available components were to be used, then 5 to 6 wheels sprung by torsion bars seem logical.

Conclusion

The Soviet experiments on the Hetzer Starr disappeared as fast as they appeared. M. Svirin claims the possibility that progress on a working prototype might have started, but that is highly unlikely. As a matter of fact, the entire project was just an experiment of testing fixed-mounted guns, as a new budget SPG based on WWII equipment was redundant and had no place in the rebuilding Soviet army. A German 75 mm gun had no place in the Soviet army, let alone after the war was already over, clearly not capable of dealing with new Western tanks. The problems of recoil damage to the hull and gun mounts were not yet fixed. The last nail in the coffin came with the development of new and more powerful recoilless guns. While harder to implement in an enclosed AFV, the whole concept was more fruitful than the rigidly mounted gun.

Soviet copy of the German Hetzer Starr. Illustration by Pavel Alexe.

Soviet Hetzer Starr Specifications
Dimensions (approx) (L-W-H)	3.70 – 2.63 – 2.10 m
Total weight, battle-ready	15-16 tonnes
Crew	4 (Commander, Gunner, Driver & Loader)
Propulsion	2x GAZ-202 70 hp enginesOr2x GAZ-80 85 hp engines
Speed	40 km/h (hypothetical)
Suspension	Torsion bar, 5 to 6 wheels per side
Armament	7.5 cm Pak 39 L/48
Armor	Armor: 60 mm angled at 30 deg.20 mm side and rear
No. Built	0, partial blueprints only

Sources:

Stalin’s self-propelled guns M. Svirin
Soviet Hetzers – M. Svirin via Soviet Hetzers (topwar.ru)
The theory of armored errors: the middle of the Great Patriotic | Warspot.ru – Yuri Pasholok
Лёгкие САУ с большими пушками | Warspot.ru – Yuri Pasholok
http://www.pzfahrer.net/starr.html
Tank Archives: Obsolete Tanks – Peter Samsonov
Tank Archives: Soviet Light Tank Destoyers – Peter Samsonov
Tank Archives: An Alternative from Gorky – Peter Samsonov

Cold War Soviet Heavy Tank Prototypes

Object 718

The Object 718 (incorrectly known as Object 705A). Illustrated by Pavel Alexe

Soviet Union (1945-1948)
Superheavy Tank – Blueprints Only

Megalophilia is a term rarely encountered in the world of military history, yet the phenomenon has been a recurring theme since the beginning of mankind (and, ultimately, wars). Massive weapons of war, envisioned to destroy and conquer any enemy resistance, more often than not failed hilariously, hurting their creators more than the enemy. In popular history, Nazi Germany is the one most often mentioned in regards to this topic. One does not even have to mention the Maus tank, Schwerer Gustav railway gun, Bismarck battleship or the Me 323 Gigant transport aircraft.

The fascination for super-heavy tanks was a common theme prior to the Second World War in several nations and continued into the war. The Soviets had their own fair share of such heresies, such as the Edward Grote’s designs, T-42, KV-4, and KV-5 and more. However, the theme of such heavy tanks slowly died during the war, with the occasional exception. One such exception was the Object 718, often called Object 705A – a 100-tonne super-heavy tank armed with a 152 mm gun and having dozens of centimeters of raw armor, as Soviet tank design moved towards more advanced protection philosophies, such as low silhouettes and steeply angled plates requiring thinner armor.

Yet, with the discovery of the German monster tanks, like the Maus and Jagdtiger, Soviet officials realized that their own heavy tanks were inferior. Although the war was over, further developments on even heavier tanks continued. On the 11th of June, 1945, the GABTU ordered the development of a 60-tonne heavy tank armed with a S-26 130 mm gun and the suspension had to be torsion bars. Kirov Chelyabinsk (ChKZ) answer to this request came in the form of the Object 705 and Object 718, while Kirov Leningrad (LKZ) came in the form of the Object 258, Object 259 and Object 260 (IS-7).

Ironically, on the 2nd of April, 1946, not even a year after the initial request, V.A. Malyshev ordered all heavy tank projects above 65 tonnes to be canceled. However, his request did not hold up in practice, with the 100 tonne Object 718 still being under development and the ultimate versions of the IS-7 weighing over this threshold.

One of the final IS-7 prototypes. While certainly a massive tank, and likely on par with the Object 718 in terms of dimensions, the 100-tonne weight of the Object 718 makes them hard to compare.
Source: Soldat.pro

Design

The Object 718 was a direct evolution from the Object 705, a lighter 65-tonne heavy tank. Both vehicles featured a rear-mounted turret for better balancing of weight and to reduce gun overhang. The Object 718 was to be armed with a colossal 152 mm M-51 gun, using two-part ammunition and two loaders. Weighing 100 tonnes on paper (a figure likely to grow as the design would transition from paper to reality), the armor would have been impressive in raw thickness, yet clever use of angling the side armor plates into a diamond-like shape, the overside protection was increased. To protect itself from infantry, soft-skin vehicles, and even aircraft, a secondary turret was added to the rear of the turret, armed with 2 KPVT 14.5 mm heavy machine guns.

It likely had a crew of 5; commander, gunner, 2 loaders and driver, in a standard Soviet crew layout. The driver sat alone in the hull, while the massive turret encompassed the rest of the four crewmen.

Silhouette of the Object 705. The Object 718 would have likely been similar in layout, just larger.
Source: TiV No. 09 2013

Hull

The exact details of the tank remain mostly unknown. Even a full blueprint of the hull is, so far, missing. Careful analysis and speculation would indicate that the hull was very similar to that of the ‘lighter’ Object 705, but lengthened to fit the larger turret and heftier rounds. The Object 718 would have been 35 tonnes heavier, out of which at least 10 tonnes would come from the larger turret and the 152 mm gun and its ammunition. The remaining 25 tonnes would likely come from thicker frontal armor, overall increased hull volume, and a new engine. This new engine would have been either a diesel or turbinepower output of 2,000 hp, to be able to reach useful speeds. This engine was likely the outcome of post-war Soviet-German work on turbine engines. The transmission was a planetary system automatic. In terms of suspension, a single torsion bar per wheel was used.

One of the main reasons behind the Object 718 was for more armor. Although the exact armor values are yet unknown, comparison to the Object 705 and other heavy tanks of the time (also taking in consideration the weight) results in the frontal hull being at least 220 mm thick, angled at circa 60 degrees. The side armor would be at least 150 mm thick angled inwards at circa 57°. The rear armor angled upwards and was at least 120 mm thick. According to a document on the project, it was to whitstand incoming shells with a muzzle velocity of 1200 m/s.

152 mm M-51

One of the few certain things about the Object 718 is the main armament, the M-51 152 mm gun, developed at Factory No.172 as a tank variant for the 152 mm M-31. In terms of ballistics, it was mostly identical to the regular M1935 Br-2 howitzer, but with considerable upgrades in other areas. Firstly, the archaic breech block door was replaced with a more modern horizontal sliding breech block. It also received the famous TsAKB style slotted muzzle brake, which could absorb up to 70% of the recoil, decreasing the need for powerful recoil absorption pistons. It still had two recoil absorption cylinders and two brake cylinders to absorb recoil, but these were considerably lighter, and in tandem with the muzzle brake, decreased the recoil from 1,400 mm (on Br-2) to 520 mm. Very noticeable is the sheer volume of the breech, which was needed to offset the long barrel. One prototype of the gun was built and passed factory tests in the summer of 1948.

Soviet slotted muzzle brake compared to a German-style muzzle brake.
Source: Tank – The Military Publishing House of the Ministry of Defense of the USSR

Turret

The only known blueprint is of the turret, a lengthened variant of the original. It almost resembles a UFO-like shape to increase the angle at which most projectiles would hit the surface. To cut down on the weight, the rear and top has been limited to around between 30 and 50 mm of armor, while the front has over 250 mm thick. The mounting of the M-51 gun is also very clear, showing the lack of gun depression. It is also significantly longer than the original to compensate for the larger recoil and potentially even turret-stowed projectiles.

On the roof of the turret, the turret ring of a second, smaller turret can be seen. This was a brand new design feature incorporated on some heavy ChKZ designs, first incorporated on the Object 726, and apparently, also the Object 718 (as the two were likely designed simultaneously). The turret resembles contemporary American tank secondary turrets, having a hemispherical shape. It was armed with a pair of 14.7 mm KPVT heavy machine guns. It was far too small for a crew member to fit in it, and was probably mechanically controlled from within the turret by one of the loaders. The idea was not entirely dropped after the cancellation of these super-heavy tanks. The Object 777 still used a similar turret, but with only one turret KPVT. For the turret traverse, ChKZ created hydraulic drives in 1948, but they were deemed unsuccessful and shortly after, the entire project was canceled.

Cutout view of the turret showing its armor thickness and the M-51152 mm gun.
Source:TiV No. 09 2013

The Object 726 model 1947, designed in parallel with the Object 718, but weighing less than half of it, at just 48 tonnes.
Source: TiV No.10 2014

The 4-tracked Object 726 mod. 1948. The second turret on top was likely very similar to that of the Object 718.
Source: TiV No.10 2014

Suspension & Running Gear

As this would be amongst one of the heaviest tanks ever designed by SKB-2, seriously strong suspension and running gear were needed. An entirely new set of large-diameter wheels was designed for the program. The Object 705 likely used the same wheels.

As per the blueprints, the wheels were steel-rimmed, clamped between two stamped steel lids. This left a distinctive space between the rim and the interior of the wheel. The same wheel system is mirrored on the other side. The two parts are held together with large bolts, creating a space for the track guides.

The suspension consisted of relatively simple torsion bars, running from the wheel straight into the narrow hull. The torsion arms were mounted in opposite facing pairs, instead of facing the same direction, like on other torsion bar sprung tanks. The spacing in-between each torsion bar pair was enough to fit another torsion bar, as seen in the blueprints.

Side cutout view of the wheels used on the Object 718. These were likely designed specifically for the project.
Source: TiV No. 09 2013

Side cutout view of the torsion arm and torsion bar attachment on the Object 718. Note the steep angle of the hull.
Source: TiV No. 09 2013

Cutout top view (left) and cutout side view (right) of the torsion bar arrangement. Note how they are mounted in opposite facing pairs, an unusual solution.
Source: TiV No. 09 2013

A Maturing Tank Force

Although being under development for almost 3 years (a very long time for Soviet standards), the Object 718 never got particularly far. Both the GABTU and Soviet officials began discouraging especially heavy tank projects. Even internally, ChKZ was focusing on other, more fruitful projects, like the IS-3 and IS-4 or various self-propelled guns.

It also started to become clear that heavy tanks were beginning to get outperformed by medium tanks. Development of the T-54 had reached an advanced stage in the late 1940s, with better mobility and lower weight, yet the firepower and armor were not far behind.

In contrast, heavy tanks, especially super heavy ones, like the Object 718, would hinder the Soviet tank force rather than improving it. Such a heavy tank, not only requiring massive amounts of money and resources poured into developing, production and maintenance, would also require an entirely new logistical force, from rail cars to mobile bridges.

Ultimately, the Object 718, alongside its lighter brother the Object 705 and its LKZ rival, the IS-7, all got their lives cut short by the Council of Ministers of the USSR on the 18th of February, 1949, where it was requested that the development of all heavy tanks and SPGs weighing over 50 tonnes should be terminated.

The Soviet Union would ‘force itself’ into adopting a new heavy tank into service, despite the rather large disappointments in the form of IS-3 and IS-4. This would be the T-10, one of most modern heavy tanks of the time. Whether or not it was necessary is up for debate. The British Conqueror heavy gun tank and American M103 heavy tank entered service in the mid to late 1950s.

Soviet heavy tank development continued into the 1950s, with very advanced designs, such as the Object 279 and Object 770, far ahead of any contemporary Western heavy tank. They were, however, redundant as by now, new Soviet medium tanks could easily outperform any heavy tank using new technologies. On 22nd July 1960, Nikita Kruschev forbade the development and adoption into service of all tanks weighing over 37 tonnes. Thus, all heavy tank development stopped.

The Object 718 (incorrectly known as Object 705A). Illustrated by Pavel Alexe

Object 718 Specifications
Dimensions (L-W-H)	7.2 – 3.7 – 2.4 m
Total Weight, Battle Ready	100 tonnes
Crew	5 (Commander, Gunner, Driver & 2 Loaders)
Propulsion	2000 hp diesel/turbine engine
Speed	35 km/h (hypothetical)
Range	Torsion bar, 7 wheels per side
Armament	152 mm M-51 gun coaxial 14.5 mm KPVT heavy machine gun Secondary turret w/ dual 14.5 KPVT
Armor	Hull armor: Approx. Front top plate: 220 mm at 55° Front bottom plate: 200 mm at -50° Side plates: 150 mm at 57° (inwards) Rear plates: 120 mm Top: 30 mm Belly: 30 mm
Total Production	0, blueprints only

Sources

Domestic armored vehicles 1945-1965 Soljankin, A.G., Pavlov, M.V., Pavlov, I.V., Zheltov
TiV No.10 2014 A.G., Pavlov, M.V., Pavlov
TiV No. 09 2013 A.G., Pavlov, M.V., Pavlov
https://yuripasholok.livejournal.com/2403336.html
The genius of Soviet artillery. Triumph and tragedy of V. Grabin – Shirokorad Alexander Borisovich

Cold War Soviet Heavy Tank Prototypes

Object 705 (Tank-705)

Soviet Union (1945-1948)
Heavy Tank – None Built

Background

In the latter stages of the Second World War, a great deal of Soviet tank design focused on improving existing heavy tanks, such as the IS-2, and building entirely new designs. This resulted in a number designs, with various degrees of performance and success, such as the IS-6 and IS-3.

After the discovery of the Maus and an in-depth look at German projects, the Soviets thought that the new imminent war against the West would require serious heavy tanks, with more armor and better guns than what they currently had. So, on 11th June, 1945, the GABTU (Main Directorate of Armored Forces) requested the development of new heavy tanks armed with the 130 mm S-26 gun, weighing 60 tonnes, and using torsion bar suspension. This led to a series of complex heavy tank and SPG designs, which would eventually lead to the heaviest Soviet tank of all time – the IS-7.

Developed and built at Kirov plant Leningrad after almost 5 years of development, the IS-7 is often regarded as the peak of heavy tank design. However, the Soviets officials’ displeasure with such heavy vehicles led to the cancellation of design and development of all AFVs weighing over 50 tonnes. The act came into practice at the meeting of Ministers of the Soviet Union on 18th February 1949, ending the IS-7’s life.

But few know of the other Kirov plant’s design, meant as a rival to the IS-7 (Object 260). Kirov Chelyabinsk (ChKZ) and Kirov Leningrad (LKZ) had been rivals for years, and so there are many parallel projects by the two factories. Their design was called Tank-705 as per the blueprints, but would eventually be known as the Object 705. The project started in June 1945 and was terminated in 1948, alongside other heavy tanks.

Development first began in June 1945, immediately after the discovery and analysis of German heavy AFVs. This triggered a series of projects over several design bureaus and factories. For ChKZ, the IS-3 was proving to be a success, and the IS-4 (Object 701) was soon to enter production. In contrast, LKZ had just lost several programs, most importantly, the IS-6. But the experience gained from it led to a series of promising designs. Fast forward a couple of years, and LKZ had full-scale mock-ups of one of the best heavy tanks ever designed, and was beginning prototype production. Meanwhile, Chelyabinsk and its design institute, SKB-2, had a series of disappointments, especially in the IS-4. In parallel, ChKZ had been working on the Object 705 and 718 (also called Object 705A) designs, but, as they were not deemed crucial or urgent, progress was slow. Further problems came with the 80th order on 2nd April, 1946 from V.A. Malyshev, when the mass of heavy tanks was limited to 65 tonnes. While the Object 705 still fit the criteria, the Object 718 did not. Yet work continued regardless.

The 1946 LKZ Object 260 was very similar to the Object 705 in terms of capabilities, although it came slightly later.
Source: Domestic armored vehicles 1945-1965

Design

All that remains of the Object 705 are two drawings, one general silhouette and one detailing the armor profile and thickness. The tank was meant to weigh around 65 tonnes, use heavily sloped armor plates, and mount a thick cast turret mounted to the rear. This was done not only to use the engine as protection, but to also offset the length of the gun. What exact engine it would have used is unknown, but likely one between 750 and 1,000 hp for it to reach the expected 40 km/h. The transmission was a planetary automatic design. It is important to highlight is the sheer size of the tank design, being 3.6 m wide and 7.1 m long (just the hull), dwarfing the IS-4 (6,682 (hull only) x 3.26 x 2.4 m).

Dark silhouette view of the Object 705 with the dimensions. This is the only known drawing showing the complete view of the vehicle.
Source: TiV No.9 2013

The crew was probably of 4: commander, gunner, loader, and driver. The crew were all situated inside the turret, with the gunner on the left side of the gun, the loader behind, and the commander on the opposite side. The driver was placed inside the turret, and would have a pivoting station, which allowed to always face the front of the hull. This was not the first, nor last, time Soviet designers would try to incorporate this idea. Two of the periscopes were mounted on the turret roof, the one on the left side was to be used by the commander and the one on the right was to be used by the loader. The driver also had his own periscope, but mounted further forwards. The gunner likely did not have his own periscope, and had to rely on his sight and/or crew callouts.

Armament

In terms of main armament, it is uncertain what the Object 705 would have used. Some sources claim it was a high-power 122 mm gun, while others state directly that it was a BL-13 122 mm gun. This was no new and revolutionary gun by the late 1940s, it was actually developed by OKB-172 in 1944, with several upgrades made later, such as the BL-13T and BL-13-1. The rate of fire varied between the different versions of the gun, as the upgraded variants had a mechanical gun rammer, but it was between 5 to 10 rounds per minute. Such long reload times were caused by the two-part ammunition. Secondary armament consisted of a coaxial 12.7 mm DhSK heavy machine gun mounted on the right side of the gun and potentially a roof-mounted DhSK.

However, a larger caliber gun (130 mm) is not entirely out of the equation, as later IS-7 designs used such a caliber, and the diameter of the barrel on the silhouette of the tank is thicker than that of a 122 mm gun. To back this theory up, on 11th June, 1945, specifications clearly stated that the gun on the new heavy tank should be a 130 mm S-26, the land version of the naval B-13. At the same time, the BL-13 was already deemed obsolete when facing German heavy tanks.

The S-26 was developed between 1944 and 1945 at TsAKB by head engineer V.G. Grabin. It was largely based on the B-13 130 mm naval gun (not to be confused with the previously discussed BL-13) with a semi-automatic horizontal sliding breech lock, slotted muzzle-brake, and barrel smoke evacuator. Rate of fire was around 6 to 8 rounds per minute. The shells weighed 33,4 kg and had a muzzle velocity of 900 m/s.

Ammunition was stored along the angled sidewalls, a solution present on most Soviet tanks with angled sidewalls. The exact number of rounds stowed is hard to estimate, but most tanks using similar guns carried around 30, split into charges and projectiles.

Digitally blue-tinted drawings of the BL-13 122 mm gun. Note that the barrel length proportions are not to scale.
Source: Warspot

S-26 130 mm gun. This was the gun GABTU requested to be mounted on the heavy tank in the summer of 1945.
Source: Domestic armored vehicles 1945-1965 Soljankin, A.G., Pavlov, M.V., Pavlov, I.V., Zheltov

Armor

A study of the drawing showcases the armor thickness and the complex arrangement of the armor plates. The upper frontal plate consists of one 140 mm thick plate, angled at 60°. On the top corners, it is met by a plate angled upwards across the upper side of the engine bay. The lower plate is also 140 mm, angled 55º from the y-axis. In terms of side armor, a very interesting idea was adopted. The two 130 mm armored side walls were brought inwards at a steep 57° angle, creating a diamond-like shape from the front. SKB-2 had used angled walls on the IS-3, but only on a minimal level for more interior space. Instead, such diamond-shaped sides were first used by the Kirov Leningrad plant on the first IS-7 design, the Object 257. This option provided excellent side protection from conventional projectiles, but also increased mine resistance, as the blast force was directed outwards. All this came as a trade-off for interior space. A major issue with this design feature is the narrow-angle created at the bottom of the tank. This space is very hard to use, and essential components like engine and transmission have to be moved up, making the tank taller. Another big issue was the suspension, namely where exactly to put it. On the Object 257, the issue was resolved by designing a brand new external suspension, using volute spring bogies like on the Sherman tank. The exact solution on the Object 705 is, naturally, unknown, but a handful of different options could have been used.

The turret was rounded and flat, creating angles between 50º and 57º. Armor varied greatly depending on the strike face, with the thickest front part being 140 mm and the thinnest roof section being 20 mm.

Cutout armor profile of the Object 705. Note the protrusions from the hull for the final drive.
Source: TiV No.9 2013

Roadwheels and Suspension

One of the most curious aspects of the design was its wheels. Seven large steel-rimmed wheels per side were used. A hint comes from SKB-2’s other super heavy tank project at the time, the massive 4-tracked Object 726 behemoth, which featured among other wheel and suspension ideas, large, steel rimmed roadwheels. There is a serious possibility of them being used on the Object 705 as well. These wheels would later become a mainstay in heavier ChKZ designs, such as the Objects 752, 757, 770, and 777, the latter two using hydropneumatic suspensions.

Steel-rimmed roadwheel from the Object 770 at Kubinka.
Source: Magic Models

Yet blueprints of the Object 718 show a slightly different set of wheels. These were drawn as steel rimmed and with deep spacing between the rims and rest of the stapled steel lids. The wheels seem to have been mostly unique to the Object 705A. The Object 705 could have used the same wheel design or something else, as the lower weight allowed for more playroom in terms of weight thresholds on the components.

Cutout view of the roadwheel used on the Object 718. These were different to other large-diameter wheels used by ChKZ.
Source: TiV No.9 2013

Implementing conventional torsion bars running across the length of the hull initially seems challenging due to the hull floor being so narrow, due to the inwards angled side walls. Yet the simple solution to this was that the tank hull was simply very wide. This allowed the side walls to keep a steep angle while still allowing for a sufficiently long torsion bar to be mounted. Such issues had been encountered by Soviet engineers both previously and later, with a variety of solutions such as bundled torsion bars, lifting the torsion bars higher up into the hull, or moving the torsion arm on the outside of the wheel.

Cutout view of the suspension (single torsion bar) used on the Object 705A. Note the angle of the hull.
Source: TiV No.9 2013

Object 705A

At some point during the development of the Object 705, an even heavier variant was designed. It would have weighed 100 tonnes and be armed with the 152 mm M-51. Just the mass alone would place the Object 705A as one of the heaviest Soviet tanks designed post-war. Yet blueprints only show specific details, such as the turret, suspension, roadwheels, and transmission. A lack of hull blueprint makes it hard to legitimize it as a complete design, and it is entirely possible that its hull never got drawn to begin with. This naturally leaves the proposal in a lot of mystery and up to significant speculation.

Conclusion – Weight Shaming

With so little information available, it is hard to properly judge the capabilities of the Object 705 and 718, even when compared to the different variations of the IS-7. The vehicles were likely designed between 1947 and 1948, at which point the BL-13 was already outclassed (Kirov Leningrad had used it on the IS-6 and other projects in 1945). So, in that respect, the Object 705 fell behind the IS-7. Yet in terms of armor, it was on par, if not even better protected than the most advanced IS-7 variant. As for the Object 718, the lack of information prevents any conclusions to be drawn, with the one and main issue being the weight of 100 tonnes. When discussing both the Object 260s and Object 705s, it is generally clear that such heavy vehicles could prove vulnerable and simply too heavy for effective battlefield use. The heaviest Soviet tank in service, the IS-4, weighed 53 tonnes and was still considered overweight and too slow. Thus it seems almost natural that the Soviet government saw the limitations and waste of resources devoted to such heavy vehicles. The final nail in the coffin for these designs was the cancellation of all AFVs above 50 tonnes on 18th February, 1949.

Object 705 rendition, illustrated by Pavel ‘Carpaticus’ Alexe

Object 705 specifications
Dimensions (L-W-H)	7.1 – 3.6 – 2.4 m
Total Weight, Battle Ready	65 tonnes
Crew	4 (Commander, Gunner, Driver & Loader))
Propulsion	1,000 hp engine of unknown type
Speed	40 km/h (hypothetical)h
Armament	130 mm S-26 or 122 mm BL-13 gun coaxial 12.7 mm DShK heavy machine gun
Armor	Hull armor: Front top plate: 140 mm at 55° Front bottom plate: 140 mm at -50° Side plate: 100 mm at 57° Top: 20 mm Belly: 20 mm
Total Production	Blueprints only

Sources

Has Own Video WW2 German Fake Tanks

Geschützwagen E 100 (Fake Tank)

Post author By Pavel Alexe
Post date April 2, 2022
7 Comments on Geschützwagen E 100 (Fake Tank)

German Reich
Self-Propelled Gun – Fake

Since the Second World War, the weapons of Nazi Germany have given rise to great myths and legends, many only lightly connected to historical reality or physical plausability. The famous Tiger tank or the massive Maus have sparked massive interest amongst amateur and veteran historians alike. This phenomenon can be seen most prominently within the military modelling community, where the surplus of pieces and time removes all limits for those ensconced by the German military’s real or imagined might. Naturally, many unique creations have been made, some completely disregarding any historical or technical factors, being part of a hobby for personal enjoyment, and not for serious historical discourse. One such creation is the Schwerer Geschützwagen Löwe 24 cm (Eng: Heavy gun carrier Lion 24 cm) created by a German modeller in the 2000s. Over a decade later, the video game company Wargaming was looking for a German self-propelled gun to fill the spot for the Tier X German Self-Propelled Gun (SPG) line in their game World of Tanks. The modeller’s abomination suited their needs.

The Model

The creator of the model is Sebastian Nast, who converted and merged a Dragon Models 1:35 E 100 model kit and a Precision Models 24 cm K4 resin kit. He did, however, make drastic changes to those parts. The Schwerer Geschützwagen Löwe is essentially a lengthened E 100 hull (one extra set of overlapping wheels per side) with the engine moved to the middle, behind the driver. The gun, a 24 cm K 4 Sf, manned by a crew of 8, is housed inside a large open-topped superstructure heavily inspired by the real Geschützwagen Grille 17/21. As a matter of fact, the entire model seems to have been inspired by the Grille, being a ‘what-if’ even larger variant. Interestingly, the creator provided a short fictional “history” of the vehicle. Its translation from German:

“As early as 1942/43, the Army Weapons Office made a demand for heavy and very heavy self-propelled guns. By the end of 1944, the Grille self-propelled gun, based on an extended Tiger II B chassis, was almost ready for serial production. The 17cm K 44 and/or 21cm Mörser 18 were intended as armaments. After detailed tests, it turned out, however, that these armaments did not bring satisfactory results. Therefore, at the beginning of 1945, the demand was made to install the new 24cm K 4, which had been newly developed in 1944 and which had made a great impression during firing attempts, in the new self-propelled gun. The Grille chassis, however, could not support this armament. It was planned that the new self-propelled gun should be based on the new E90 / E100 chassis. Codename for this project was Hummel/Wespe. Army introduction was planned for 1946 at the latest. Due to the events of the war, however, this project did not get beyond the drawing board stage. The first preliminary studies are said to have been very promising…”

The Schwerer Geschützwagen model, as seen on Ebay.
Source: Ebay

The modeller provided a series of images, showing the SPG next to a Grille model, and being loaded by a half-track with ammunition. Nast calls it a “historical-logical reconstruction” and the most probable variant if the E 100 hull would have ever been used as a SPG. You can find more images of the model and a short text by Nast himself on the model here, written in June of 2001.

The model was put up for sale on Ebay by seller ‘Goldenstern114’ in the summer of 2020 and sold that same October for €176.

Size comparison of the SPG with the E 100 Salamander, another fake E 100 based vehicle. Note how much longer the Geschützwagen hull is.
Source: Nast-sonderfahrzeuge.de

Historical elements

Like most such scratch builds, the Schwerer Geschützwagen is based on some form of reality. The E 100 chassis was, of course, a real thing, that was partially built and completed by Adler in January 1945 at Hauestenbeck, where the Allies would later find it in early April 1945.

The unfinished E 100 hull, as found by the Allies.
Source: World War Photos

The gun, the 24 cm K 4, was also historical, but never left the drawing board and was certainly never tested, as Nast claims. Regardless, it would have been too big to fit, even in the extended E 100 hull. There were drawings of it fitted on three Tiger heavy tank chassis, or on a chassis similar to the Gerät 040/041, and even then, in an open fashion, similar to that of a railway gun. The K4 was to replace the K3 cannon and, in 1941, a contract was given to Rheinmetall-Borsig and Krupp to develop the gun. It required high mobility, a projectile weight of 160 kg and a range of 48/49 km. The barrel length was 17,280 mm (L/72) or 16,000 mm (RhB Special Panzer). The towed piece weighed 65,500 kg when transported, and 55,000 kg combat weight.

Unfortunately, the Precision Models resin kit does not seem to remotely resemble the plans of the real weapon. Nast enlarged the weapon, but it is still far off, and looks more like the 24 cm Kanone 3.

Rheinmetall’s 24 cm K4 on Tiger tank chassis for transport. This paints a view of just how large the K4 truly was.
Source: H.L. Doyle

There were plans to make a self-propelled assault gun out of the E 100, namely the 15/17 cm Sturmgeschütz auf E 100 Fahrgestell, an extremely well-armored vehicle meant to take on heavy Allied tanks and fortifications from long range, but it never went past mock-up stage. Apart from blueprints showing the gun mantlet and mount, everything else has been lost.

Practicality

Judging something for more than it actually was meant to be is never a good thing, but for the sake of the argument, a quick analysis of the vehicle can show how infeasible the design would have been. Firstly, the chassis still keeps the E 100 levels of protection, with a maximum thickness of 200 mm, and the heavy side panels, completely useless considering the almost paper-thin gun housing and open-top. Also, the long-range of the 240 mm K 4 cannon would have made any armor pointless, as it would fire from far behind the frontline.

Nonetheless, the weight of the vehicle was still an estimated 137 tonnes. The engine, an unspecified 1,500 hp Maybach V12, would have propelled the SPG at a whopping 42 km/h, a completely exaggerated number. The E 100 tank, weighing less than the SPG, would not have been able to reach this speed. Combined with the incredible strain on the transmission and destructive ground pressure, the vehicle would have been a mechanical disaster, unable to be produced by a struggling Germany in 1945. German heavy tanks at half this weight and less struggled mechanically, let alone something of this size.

Nonetheless, the Schwere Geschützwagen was just an interesting model, with a moderately sensible ‘history’, albeit exaggerated in its mechanical aspects. However, this is nitpicking when discussing an amateur model kitbash.

World of Tanks

Things took a weird turn when Wargaming needed a vehicle to fill their top of the line Tier X spot for German artillery. The lower tiers are filled in by historical vehicles, such as the Hummel, G.W. Panther or Grille 17/21, but at tier VIII and X, Wargaming’s research team seemed to struggle. Thus, two fake vehicles were introduced, the G.W. Tiger P and G.W. E 100. While the G.W. Tiger P is a lengthened Tiger P hull with a Geschützwagen Grille casemate, probably a Wargaming invention, the G.W. E 100 is heavily inspired by the Schwere Geschützwagen Löwe model.

Appearance

Wargaming shortened the SPG back to the regular E 100 hull size, but did keep the rear overhang and most other visual aspects of the original model, like the gun shield and camouflage net holders. They did change the other performance aspects for game balancing. Interestingly, World of Tanks also provides a false history of the G.W. E 100, however, it never mentions it as being fake.

“Project for a 210 mm mortar on the chassis of the E 100. The vehicle was never produced.”

Most importantly, the gun was changed. In the game, it now has a ‘21cm Mörser 18/2’, a fictional name for the real 21 cm Mörser 18, but with the slightly changed name to differentiate between the two, as the latter is present in lower tier vehicles. The real Mörser 18 was a replacement for the 21 cm Mörser 16 from WWI. It had a weight of 16.7 tonnes, a range of 16,725 m, a muzzle velocity of 550 m/s and a High Explosive (HE) shell weight of 113 kg. The fictional vehicle can carry 30 rounds. There is an openable port on the front of the superstructure, which was probably meant to allow the use of a direct fire sight. A large gun crutch is present at the front of the top of the hull.

The much more rational World of Tanks model, but altogether an unnecessary mongrel, which can come off as something real.
Source: MMOWG.net

The engine and other performance indicators were also changed, the engine being a Maybach HL 234 TRM P45, with a 900 hp output. This was a real engine that was hoped to reach up to 1,200 hp, so this variant is in line with historical reality (the project failed to reach the desired engine power). The engine has been moved from its rear position to the center of the vehicle, similar to the Jagdpanzer E 100 vehicle from World of Tanks. This was a common change for German artillery SPGs, also being a feature of the Hummel, Wespe and Grille Ausf.M. The transmission remained at the front, as on the regular E 100. The exhausts were moved to the front of the superstructure, an interesting location. In game, the G.W. E.100 can reach a theoretical top speed of 40 km/h, again probably overly optimistic for the transmission, suspension and engine, although the vehicle usually drives at much lower speeds.

In terms of weight, it is 87 tonnes, giving it a hp/tonne ratio of 10.34, with a well-armored hull, with 80 mm at the front, 50 mm at the sides, and 40 mm at the rear. This is significantly less than on the real E 100 tank hull, which had 200 mm of angled armor at the front, 120 mm at the side and 155 mm at the rear, so this fake SPG version would have been based on a new-built chassis, not on the already built E 100 hull from Adler. There are 60 mm thick armored skirts on the sides, originally designed for the E 100. These significantly improved the protection over the side and tracks, which were otherwise rather thin, at least compared to the rest of the tank, and flat. However, these are notably useless for a long-range artillery SPG and would represent dead weight. They were probably added in because they are a distinctive part of the E 100 look, and not for historical purposes. Two tow hooks are present on the front of the hull and another two at the rear.

The crew also dropped to 6 (commander, gunner, driver, radioman, and two loaders), with the driver and radio operator in a different compartment in the front of the vehicle, separated from the fighting compartment by the engine. The driver has a single periscope pointing toward the front, right in front of his hatch. There was no hull machine gun on the E 100 or on this vehicle. A single Notek lamp is placed at the middle of the front glacis. The rest of the crew is placed in the rear superstructure which they can access through a double door at the rear, which would probably have been kept open during firing in order to allow ammunition resupply from ammunition half-tracks. The large metal plate present at the rear of the Grille 17/21, meant to assist with turning the vehicle faster when deployed, is notably absent from the G.W. E 100.

Rear-top view HD model of the G.W. E 100 in World of Tanks.
Source: MMOWG.net

Historical Alternatives

By now, fake tanks are more common than should be acceptable in a game that variously styles itself as realistic, historical or accurate. In the early days of World of Tanks, such fake vehicles used to be reserved only for spots that could not be filled with historical vehicles. Oddly though, there are real German designs that could fill in the spot for both the G.W. Tiger P and G.W. E 100. Walter Spielberger mentions in his book ‘Tiger and its Variants’ of self-propelled guns built using Tiger elements (perhaps the Grille chassis itself) armed with 305 mm and 420 mm Czechoslovak Škoda mortars. Alternatively, the 30.5 cm L/16 auf Sfl. Bär, armed with a 305 mm and designed by Krupp in 1943, also used Tiger components, despite being meant as a heavy assault mortar. Why these were not implemented instead, is hard to say.

There were rumors in 2013 that a second German artillery branch would be added, including the Sturmtiger and eventually the Bär at a high tier, which may have been the reason why these vehicles were not used. The rumors have not yet materialized. Other rumors also claimed that Wargaming was replacing the G.W. E 100 with the 30.5cm / 42cm Schwerer Granatenwerfer auf Selbstfahrlafette. While the two variants differed a little, they were largely identical. Developed at Pilsen in early 1945, they weighed between 55 and 65 tonnes. Most likely discovered by Yuri Pasholok, Wargaming historian at the time, it is not clear why they have not replaced the G.W. E 100. Ultimately, Wargaming never has and most likely never will replace the G.W. E 100 or the lower tier fake G.W. Tiger P because of the controversy surrounding self-propelled guns within World of Tanks.

The 30.5 cm L/16 auf Sfl. Bär was and still is an acceptable historical alternative to the G.W. E 100.
Source: Doyle

The 42 cm Schwerer Granatenwerfer auf Selbstfahrlafette.
Source: For the Record

Conclusion

Starting off as a typical model scratch built by a modeler, the G.W. E 100 has become an iconic fake tank due to its almost decade-long existence within World of Tanks. Even though it is a more ‘innocent’ fake, it is still a fabrication that is here to stay because of Wargaming’s satisfaction with how it fits into the German artillery line, and their lackluster care and attention to historical realism, especially nowadays, when entire tech tree lines are falsifications.

G.W. E 100 Specifications (WoT Version)
Dimensions (L-W-H)	≈ 9.000 x 4.480 x ≈ 3.500 m
Total Weight, Battle Ready	87 tonnes
Crew	6 (Commander, Driver, Gunner, Radio Operator, 2x Loaders)
Propulsion	Maybach HL 234 TRM P45, outputting 900 hp
Speed	10 – 40 km/h
Armament	1x 21cm Mörser 18/2 (30 rounds)
Armor	Hull: Front: 80 mm Side: 50 mm + 60 mm sideskirt Rear 40 mm Casemate: Front: 75 mm Side + Rear: 40 mm
Total Production	none; fake vehicle

Sources

http://nast-sonderfahrzeuge.de/fotosammlung/displayimage.php?album=37&pos=10
https://wiki.wargaming.net/en/Tank:G61_G_E
https://picclick.de/Schwerer-Gesch%C3%BCtzwagen-L%C3%B6we-24cm-Prototyp-Entwurf-135-143768685952.html
https://tanks.gg/tank/gw-e-100/model
http://www.nast-sonderfahrzeuge.de/images/militaer/loewe/page_01.htm

Cold War Soviet Prototypes

Object 715

Artist interpretation of the Object 715, as per the blueprints. Illustration by Pavel Alexe.

Soviet Union (1946-1947)
Heavy Self-Propelled Gun – Partial Blueprints Only

The Object 715 was a heavy self-propelled gun based on the chassis of the IS-4 developed by SKB-2 at Kirov Chelyabinsk plant (ChKZ). A direct successor to the Object 704, in turn based on the IS-3, the Object 715 never even had full blueprint studies before the design was canceled due to the shifting in military philosophies, with heavy gun platforms falling out of favor with militaries across the world.

Background and Development

The end of war usually indicates a moment of peace and joy, and in tank-related terms, the cancellation of many designs and projects. However, the end of the Second World War could not have been any more different. The clear political and military tensions between the USSR and Western nations meant that tank development never really halted after the defeat of the Axis powers. As a matter of fact, the Soviets invested heavily into more powerful tanks. So much so that many programs overlapped with each other, such as the IS-3 and IS-4 heavy tanks for the SKB-2 (design bureau of the Chelyabinsk Kirov plant) alone.

Surviving IS-4M heavy tank.
Source: Pinterest

The IS-4 (designation Object 701), like the IS-3, was meant to replace the IS-2 heavy tanks. Envisioned to be the pride of the Soviet tank forces, the IS-4 was given extremely thick armor, weighing 60 tonnes, and driven by a 750 hp V-12 diesel, allowing it to reach up to 43 km/h. However the IS-4 would end up becoming a very troublesome tank, with serious reliability issues throughout its development and service life, caused by its heavy weight, unreliable mechanical components and poor design.

Most importantly, the IS-4 had the same 122 mm D-25T gun like the IS-2 and IS-3. Production started in March 1947 and ended just a couple of years later, in 1949, when all activity on tanks weighing over 50 tonnes was canceled. The tank proved to be too heavy and sluggish and poorly constructed. Another small batch of 25 units was built in 1951 with some upgrades, called IS-4M. All previous tanks were upgraded to this level. In total, only 249 were built.

The idea of an self-propelled gun based on the Object 701 appeared in February 1945, after the positive conclusion of the trials of Object 701 prototype No.5, as it was proposed to enter production and that ISU-152 and ISU-122 SPGs be based upon it. In 1947, with the IS-4 entering mass production, the ChKZ plant began development of several derivatives based on the IS-4. One of these was the Object 715, a heavy SPG based on the hull of the IS-4. The SKB-2 design bureau had done something similar just a couple years earlier, designing the Object 704 SPG right after the IS-3 (Object 703). One prototype was built in spring 1945 and tested in the autumn of that year. State trials of the Object 704 revealed several issues with the SKB-2 SPG. The iconic sloped armor sides severely decreased the space available inside the crew compartment, hindering the loader from accessing all the shells properly, and the breech operator’s position was very tight, having a hard time extracting the explosive charges. This also led to a rather limited ammunition count. Trial officers recommended that the walls were to be made vertical again, like on the ISU-152.

The single prototype built of the Object 704 survives today at Kubinka, where it was brought for testing in 1945. Source: World War II Wiki

An exact timeline of the development of the Object 715 is hard to establish. At some point during 1946, work began on the Object 715, when interest from the state in heavy SPGs armed with 152 mm guns grew again. SKB-2 would base this SPG on their new IS-4, which had gotten far in development. Interestingly, their rival, the Kirov plant in Leningrad, also got far with their designs on the Object 260 (IS-7) heavy tank and based their SPGs on this chassis.

Purpose

The versatility that heavy SPGs showed during the Second World War had greatly impressed the Soviets. Their large-caliber guns, whether 122 mm or 152 mm, were powerful enough to deal with almost any kind of threat. Casemates, machine gun nests, and other static defenses, would be deleted from the face of the earth, doubling down as iconic propaganda machines to this day. Even the heaviest German tanks would prove vulnerable to a direct hit from a 152 mm shell, cracking open welds and rupturing armor via pure momentum and force.

Deep Battle doctrine, a complicated and much-debated philosophy from the first Soviet use of tanks, proved to be effective after the Axis’ defeat. Here, self-propelled guns would prove important and critical in weakening enemy defenses prior to an attack, but support infantry and tanks with unparalleled firepower. Theoretically, such self-propelled guns would target remaining enemy troops after indirect fire shelling, which would allow the infantry to push along with the ‘regular’ tanks. But reality pushed these vehicles to adopt a more aggressive style of combat, acting a lot more like an assault gun. The ISU-152’s armor proved insufficient for such purposes, which was why the Object 704, at first designed at the beginning of 1945, focused greatly on protection, with thick, angled plates across the casemate.

But after the war, the philosophy and environment changed. Raw armor thickness simply would not cut it. Battle tanks had increasingly more powerful guns and warfare got more mobile. To cope with these changes, designers had to increase the engagement distance of SPGs, in turn allowing for less armor. New medium and heavy tanks, both domestic and foreign, proved to be more and more self-sufficient in all areas. Self-propelled guns were no longer needed on the first line of attack and could afford to cut down on protection by engaging from as long ranges as possible. This would have required a seriously powerful gun.

Design

The design of the Object 715 was almost identical to that of the Object 704. The front of the vehicle was dominated by a large gun mantlet. This mantlet was a redesign of the one found on the Object 704, where water used to gather into the gap beneath the mantlet, meant to allow the mantlet to depress the gun. On the new design, the mantlet was depressed straight into the fighting compartment, and protected by an outer sleeve along the sides. The roof was also redesigned to allow the gun to depress more.

Only available blueprints of the Object 715. The gun shown is likely a modernization of the M-31 152 mm, sometimes called the M-48.
Source: Tank Archives

The most noticeable feature of the new SPG was the small volume of the casemate. The new armament had almost 3 times less recoil distance compared to the Br-2 howitzer. This allowed the designers to shorten the casemate significantly. The blueprints also show the lower hull of the IS-4 chassis, which has been altered to fit the casemate. Of great interest is the armor thickness of the lower plate, or lack thereof. Despite these changes, the blueprints of the Object 715 perfectly match and fit into those of the IS-4. The exact mass is unknown, but some sources claim 60 tonnes. While not impossible, this meant that it would have been heavier than the IS-4 itself.

Using the IS-4 chassis, most mechanical components remained the same.The engine was a V-12 diesel outputting 750 hp at 2,100 rpm, coupled to a 6-speed forward, 2-speed reverse manual gearbox.

Crew

Soviet tanks are not known to have vast and lavish crew spaces, and the Object 715 would have been no exception. This trend began with the pressures of the war in the 1940s, forcing designers to make sacrifices. This issue continued until the 1950s, from which point crew ergonomics improved greatly.

The crew likely consisted of 5: commander, gunner, driver, loader, and loader assistant (formerly breech operator), all cramped in a small casemate. They were positioned in the classical formation, with the driver on the left side of the gun, controlling the tank with two tillers. The driver had one MK-4 periscope for vision outside, increasing his reliance on the commander for directions. Communication within the tank was done via a TPU-4F intercom, with headset and microphone. While it is hard to prove, it is very likely that each crewmember had their own entry and exit hatch, like on the Object 704. Shared hatches would have been very cumbersome, as the gun took up a lot of space.

The gunner was seated behind the driver, on a small seat, attached close to the gun breech. For vision, the gunner had the main gun sight, a TP-47A, and a secondary horizontal (azimuth) ZIS-Z sight was also provided, for indirect fire. It protruded from the hull and was protected by an armored housing. Hand crank controls for elevation were also available for the gunner. Like on previous SPGs of this type, aiming the gun was a team effort, with the gunner controlling the elevation, and the traverse being controlled by the breech operator sat behind him. This was the unfortunate outcome of letting the individual tank factories design the horizontal traverse and not the gun factory (Factory No.172).

In previous vehicles, the breech operator was tasked with opening the breech, controlling the gun traverse and loading ammunition charges. The shells, although being two-part rounds consisting of charge plus shell, weighed between 43.56 kg and 48.78 kg. For this reason, it was deemed necessary to include a loader assistant that would remove some of the strain from the loader. Exact crew positions and the ammunition layout are not present in the drawing, but judging from previous similar vehicles, the ammunition was stored on the sidewalls, with the projectiles on the right wall and charges on the left.

The loader sat opposite to the loader assistant, on the other side of the breech. The loader was tasked with loading the shells and firing the coaxial machine gun, likely a 12.7 mm DShK, and operating the potential external anti-aircraft machine gun, also an 12.7 mm DShK (not featured on the partial blueprints).

Finally, the commander sat in front of the loader, to the right of the gun. The commander’s main task was coordinating the crew, scanning the battlefield, and communicating with other units via the 10PK-26 radio, with a stationary range between 20 km to 25 km.

Armament: the M-31 and M-48 152 mm

At first, the armament was to be a 152 mm gun developed at factory No. 172, the M-31. The ballistics were mostly identical to those of the regular M1935 Br-2 howitzer, but with considerable upgrades in other areas. Firstly, the archaic breech block door was replaced with a more modern horizontal sliding breech block. It also received the famous TsAKB style slotted muzzle brake, which could absorb up to 70% of the recoil, decreasing the need of powerful recoil adsorption pistons. It still had two recoil absorption cylinders and two brake cylinders to absorb recoil, but these were considerably lighter, and in tandem with the muzzle brake, decreased the recoil from 1,400 mm (on Br-2) to 520 mm. Other improvements were an automatic barrel smoke evacuator, and the TP-47A direct fire sight, and ZIS-Z sight for indirect fire. Very noticeable is the sheer volume of the breech which was needed to offset the long barrel. One prototype of the gun was built and passed factory tests in the summer of 1948.

The M-31 gun was incorporated into the Object 715 in late 1947, however, the original plans of the Object 715 were rejected by the military, sending the SKB-2 designers back to the drawing board. The complaints came from the integration of the gun into the IS-4 chassis. It was seen as cumbersome, tight and hard to coordinate. Meanwhile, Plant No.172 developed an upgrade of the M-31, the M-48.

Plans for the M-48 were submitted for review to the Soviet state by plant No.172 on 9th August, 1946, which were approved in November. It increased muzzle velocity to 1,000 m/s and featured a slotted muzzle brake with an efficiency of 59%. A horizontal semi-automatic breech block was also designed in two versions, pneumatic and mechanical. The final draft of the gun was submitted on the 21st of June 1947 and approved for prototypes and testing. Three were built and tested. From here onwards, what happened to Object 715 is unclear. When exactly and how the M-48 was incorporated remains a mystery. It is possible that it was rejected once again, or the project was shelved for a future request, with work switching to other areas.

As secondary armament, the Object 715 had a 12.7 mm DShK heavy machine gun, loaded by the loader.

Armor

As the new weapons that were proposed allowed for greater engagement distances, the armor became less relevant. Any excessively thick armor, combined with the massive guns with great overhang, and the IS-4 chassis simply could not have handled the stress on the first set of torsion bars. Thus, the armor was made thinner but more angled. However, this was not to the extreme seen on the Object 704. The frontal plate was 100 mm thick angled at 45°. The lower plate was around 30 mm angled at -40°. Side and cheek armor values are unknown. The rest remained the same as on the IS-4 tank.

Fate

Plant No.172 agreed with the Kirov Chelyabinsk SKB-2 plant to use the M-31 in the Object 715, but also with Kirov Leningrad to use the same gun on their Object 261/Object 263 SPGs based on the IS-7, once again leading to a direct competition between the two rival factories.

In addition, Plant No.172 presented on 23rd August, 1948, a new upgraded gun, especially designed for the IS-7 based SPGs, which would eventually use the 130 mm S-70 gun. The IS-7 based SPGS only reached scale model stage before they were all canceled on 16th February, 1949, when the Council of Ministers of the USSR canceled all development and production of heavy tanks above 50 tonnes. This included the troublesome IS-4 tank subsequently cancelling all variants based upon it, including the Object 715. The concept of Heavy SPGs was once again considered with the Object 268 program, from where they would be sealed off for good.

Conclusion

While it was one of the most powerful direct fire SPGs ever designed, the shortcomings of the IS-4 platform and the shift from large guns on heavy chassis to other design philosophies, such as ATGMs, led to its demise. The Object 715 remains, to this day, one of the more mysterious Soviet post-war designs, with nothing but a half-drawn blueprint remaining.

Object 268 final version, which resembles the Object 715, despite being designed and produced by Kirov Leningrad a few years later.
Source: Google Sites

Artist interpretation of the Object 715, as per the blueprints. Illustration by Pavel Alexe.

Object 715 specifications
Dimensions (L-W-H)	6,682 (hull only) x 3.26 x 2.4 m
Total Weight, Battle Ready	circa 50 tonnes
Crew	5 (Commander, Gunner, Driver, Loader & Breech operator
Propulsion	V-12 Diesel engine, 750 hp
Speed	40 km/h (hypothetical) (25 mph)
Armament	152.4 mm M-31 howitzer or 152.4 mm M-48 howitzer coaxial 12.7 mm DShK heavy machine gun
Armor	Hull armor: Front top plate: 100 mm at 45° Front bottom plate: 30 mm at -50° Top: 30 mm Belly: 30 mm
Total Production	0; blueprints only

Sources

Domestic armored vehicles 1945-1965 Soljankin, A.G., Pavlov, M.V., Pavlov, I.V., Zheltov
Technics and weapons (TiV) 1996 06, M.V. Pavlov, I.V. Pavlov
Tank Archives: The Last Soviet Heavy Tank Destroyers
The genius of Soviet artillery. Triumph and tragedy of V. Grabin – Shirokorad Alexander Borisovich

Has Own Video Modern Romanian Armor

Dacia Duster Army Technology Demonstrator

Post author By Pavel Alexe
Post date January 24, 2022
5 Comments on Dacia Duster Army Technology Demonstrator

Dacia Duster TD based on the 2010 model. Illustration by Pavel Alexe, funded by our Patreon Campaign.

Romania (2010-2014)
Light Utility Vehicle – 3 Built (2 Machine Gun Cars, 1 Pickup)

In 2013, a strange curiosity was shown at the Romanian 1st December parade, a matte green Dacia Duster with a remote control weapon station with a 7.62 mm machine gun on top, mounted on a tubular steel frame.

The Car

The vehicle at the 1st December parade was entirely based on the Dacia Duster, a light civilian Sport Utility Vehicle (SUV) built by Dacia, a subsidiary of Renault Group. The company was first established in 1966 by the Romanian communist Government and the French company Renault to build, under license, the Renault 8 and later the Renault 12. After the fall of Communism in Romania in 1989, and with the Dacia suffering from poor privatisation, suffocated by the vastly superior foreign cars, the company was bought by Renault in September 1999.

While initially focusing on super cheap sedans, such as the Dacia SuperNova and Dacia Logan, in 2010, the company released the Dacia Duster at the Geneva Motor Show. Although rugged, filled with plastic, and rudimentary, it was met with appreciation in its home country and surrounding nations, with almost 70,000 units sold in 2010 alone. The name Dacia Duster had been previously used by the Romanian state to export the ARO 10 in the UK.

Dacia Duster at the Geneva Motor Show, 2010.

Army Dacia?

Romania had plenty of experience with SUVs prior to the Duster. The ARO factory had built the entire automotive park of the Romanian military, but also widely used by other state agencies, such as the Securitate and Miliție, and different enterprises. In the military, most were used in the way they were built out of the factory, but some featured extra armor or even weapons.

ARO 240 series with split screen and a 73 mm recoilless rifle.
Source: ARO Forum

The Army Dacia seen on 1st December parade in 2013 was a combined effort to revitalise the dead defence industry, but also replace the ageing ARO cars, that were still the majority of the unarmored cars in the Romanian Army.

The vehicle was met with raised eyebrows and big smiles. Some were laughing at the seemingly stupid look, while others realised what collaboration between Dacia and the military meant. It was based on the 2010 model year of the Duster with the Laureate trim level.
Source: Romaniaperoti.ro

It was named the Duster Army, specifically designed under a three year period by engineers from Renault Romania for the needs of the Romanian Army, and was tested at the UMB testing range Mihai Bravu, where civilian journalists were shown a firing test and a driving test. It was developed by RTR (Renault Technologie Roumanie), Romturingia, UMB (Uzina Mechanica București), Electro Bit, and specialists from the Ministry of Defence armaments department. The idea belonged to RTR, who built the car, Romturingia made the steel frame, and UMB the remote turret. Viorel Salan, head of the RTR at the time, said “With the prototype, we wanted to show what can be done”. The car was virtually a Technology Demonstrator. He then expanded with:

“If the army will be interested, we can sit down and produce it. We chose working with Romturingia, because we are talking about a vehicle built in small numbers with a special purpose, something that couldn’t’ve been done on the regular Duster’s production line.”

Despite the comical look of the car, it is filled with gadgets and possibilities for further upgrades. The roll cage is mounted externally to allow for more interior space, and to support the weight of the RCWS (Remote Controlled Weapon Station). There are 4 attaching points to the frame of the car which allow the addition of heavy equipment, such as a plow. On the rear, a tow hook is attached and to the front, a detachable Warn winch is mounted. Curiously, the winch and the Goodyear Wrangler HP 215/65 R16 tires, along with the 4 LED lights (2 on each side) are some of the only imported products, the engineers realising the importance of reviving and sustaining local industries, while also making the vehicle easier to market. The signal LED lights were imported from the US because of the international military vehicle signaling laws. In addition, there are two front mounted masked position lights, made for nighttime maneuvers. The car has a blackout system, switching off all external and interior lights, including the dashboard lights. The switch is mounted on an additional box, on top of the dashboard. A green vinyl wrap has been applied to the entirety of the car as a form of provisory camouflage. The Duster does not have any sort of external armor. According to Salan, metal armor would be too heavy, but kevlar armor can be mounted if desired. Yet there were steel armor plates along the belly of the car, one in the front, for the engine and gearbox, one for the gas tank and one for the rear differential.

The covered civilian headlights, along with the signal lights and night masked lights.
Source: Auto-bild.ro

Also above the dashboard is a switch for the 24 V system. The car runs on regular 12 V, but an additional 24 V battery has been added in the boot to suit military standards. In addition, on the left side of the boot, there is a transformer sending 220 V for two outlets.

A 34V outlet on what was once the window between the C and D pillars.
Source: Auto-bild.ro

Turret

The most peculiar part of the car was, of course, the machine gun turret. It was made at UMB, with a weight of 135 kg (300 pounds) and costs more than twice the price of the Duster. It is controlled remotely, from the inside, with the use of a joystick, similar to those used for gaming, through which the gun can be moved, aimed, and fired. An 11 inch screen is used for display. A special software shows how many bullets are left, and can also show the position of friendly, and enemy troops, just like in a first-person shooter. On this pilot model, the screen is mounted above the glovebox, in front of the right-hand passenger, and the joystick is on a mobile metal support.

The UMB RCWS, with a 7.62 mm machine gun.
Source: Auto-Bild.ro

The FCS of the Dacia Duster Army pilot model. Note the switchbox above the AC ports.
Source: Auto-bild.ro

All the additions to the base SUV altered the Dacia Duster’s driving style and capabilities. The 135 kg turret raises the center of gravity of the car, which can be felt in corners. The engine is a Diesel 1.5 dCi 110 hp with 4×4 drive. The extra equipment (excluding the turret) adds up 140 kg, for a total of 275 additional kilograms. This can be felt, even if on bumps the ride quality is good. Driving in a straight line, the Duster Army can reach 120 km/h (75 mph).

The Duster firing its 7.62 mm machine gun. Note the “probe” on the license plate, meaning it is just a prototype.
Source: Auto Industry News

Dacia Duster Army 2.0

A year later, at the 1st December parade, the Duster Army was back. This time, two 2014 model Dacia Dusters were shown. The first was very similar to the previous one, but with a new RCWS, equipped with a .50 cal. The exact turret is unkown, but it is also a Pro Optica produuct, similar to the Anubis RCWS. The second was a pickup mounting the Romanian Pro Optica Artemis Medium Range surveillance cameras. According to Pro Optica, features an color camera, uncooled thermal camera, “eye safe” laser rangefinder and the option to isntall a radar and laser target designator, all on an elevatable pan and tilt platform. Most notable is the very unorthodox camouflage pattern, consisting of small and intricate black, green, brown and beige color splashes. This was also a vinyl wrap and not painted/sprayed upon the body. Unfortunately, the Dacia Duster Army was never ordered, but it strengthened relationships between companies and was a good technology demonstrator for what can really be done with such a budget car.

The 2014 Duster to the left is very similar to the 2013 Army, but has a new FCWS. The pickup model has a 360° rotating turret with cameras for reconnaissance purposes. Note the white ARO in the background, still a common sight at the time.
Source: FotoStefan

Another variant of the Duster Army was shown at BSDA 2016, where a Duster pickup was shown with 4 ACF tracks and a Romanian Digital BIT DShK heavy machine gun RCWS on the platform, namely the AGIL 127 ERLG. This vehicle was also sold and marketed by Digital BIT. The ACF tracks are mechanically attached directly to the drivetrain of the car and requires little prior preparation, specifically 1 hour for 1 ma, according to ACF tracks. They allow the light 4 wheel drive car to cruise over muddy and snowy ground at high speeds, and a maximum speed on roads of 60 km/h. They decrease ground pressure by 15 times and increase the ground clearance to 210 mm. Dacia Dusters with ACF tracks have been tested by the ambulance services and Gendarmerie.

Dacia Duster pickup with DShK RCWS and 4 independent drive ACF tracks at BSDA in Bucharest. These tracks transform the regular axle drive into the track, and can steer the same way the wheeled car does.
Source: acftrack.com

Dacia Duster Army 3.0 Hoax, the Scorpion Trail

In December 2020, images were leaked by Dacia Duster Trails, a fan group website, allegedly showing the construction of a new special military Dacia Duster. Two versions were initially named, a troop transport variant, with heavy STANAG level 3 armor (out of kevlar and steel plates) and STANAG level 2 windows. This armor would be optional.

One of the photos leaked from the Dacia plant, allegedly showing a new military Duster.
Source: Rumaniamilitary

The second version would be for reconnaissance and scouting, featuring a drone launcher, carrying 2 attack drones, capable of firing AG7 warheads, and 3 surveillance drones, or only 4 surveillance drones. Alternatively, it could be equipped with a 81 mm mortar, supposedly capable of firing HEAT rounds up to 5.5 km. This version had only 2 seats (where the crew operating the equipment went is unclear), would be amphibious, and had a whopping STANAG level 3 to 4 protection.

Poster describing the incredibly fantastic Duster Scorpion Trail.
Source: Rumaniamilitary

Sadly, but naturally, this was a hoax. While never confirmed, it is clear that it was done by somebody unfamiliar with armored vehicles and military technology. The Dacia Duster, although robust as a civilian vehicle, was never meant to carry particularly heavy weights. So a Duster with any level of protection, a mortar or drones, and amphibious kit would be impossible. The strain on the suspension, chassis, engine, and transmission would be way too large. If these components were to be upgraded, the price would be too large, and would not justify the conversion when an already designed military vehicle could be bought.

A stock 2017 model Dacia Duster from the Romanian Military Police.
Source: MApN facebook

Conclusion

The Dacia Duster has entered the Romanian Military and has seen extensive use, albeit as a stock factory vehicle, with occasional upgrades for transport of goods and specific tasks, but never weapons. The Duster, despite being light, affordable and a great off-roader, is a car deemed underpowered by civilians. It is simply not a good platform for carrying heavy weights, thus making it impossible to add armor or close range weapons.

Dacia Duster TD based on the 2010 model. Illustration by Pavel Alexe, funded by our Patreon Campaign.

Sources

http://www.autotestmagazin.ro/duster-army-chemat-la-oaste/
https://www.romaniaperoti.ro/stiri/stiri-auto/duster-army-noua-creatie-a-dacia-pentru-armata.html

Date tehnice si imagini cu noua Dacia Duster Army NATO -Versiunea militara a Daciei Duster 2014

https://www.auto-bild.ro/teste/dacia-duster-army-cu-duster-la-razboi-30488.html

Dacia Duster Army ar putea echipa forţele române. Anunţul a venit azi – GALERIE FOTO

https://www.car.info/en-se/dacia/duster/duster-2018-16489285/specs
https://www.acftrack.com/dacia-duster/

ARTEMIS® Medium Range

Dacia Duster Technology Demonstrator specifications
Dimensions (L-W-H)	4.315 x 2.000 x 1.625 m (14 x 6.5 x 5 feet)
Curb weight	1,670 kg 3681.72 lb
Crew	5 (driver, turret operator + 3 passengers)
Propulsion	1.5 dCi 110 hp with 4×4 drive
Speed	120 km/h in straight line 60 km/h with ACF tracks
Armament	7,62 mm / .50 cal / DShK 12,7 mm machine gun turrets
Total Production	2 SUV + 1 pickup

Cold War Soviet Fake Tanks Fake Tanks

K-91 World of Tanks Fake Version

Post author By Pavel Alexe
Post date November 15, 2021
9 Comments on K-91 World of Tanks Fake Version

Reproduction of the K-91 fake tank in WoT by Pavel Alexe.

Soviet Union (1949)
Heavy Tank – Fake

In the years that followed the end of the Second World War (Great Patriotic War), the Soviets designed a vast amount of armored vehicles. Some were mass produced in the tens of thousands, while some never left the drawing board and were buried in archives and drawers for decades. An example of the latter are the K-91 tanks designed by OKB IC SV (Design Bureau of the Engineering Committee of the Armed Forces) in 1949. These were only rediscovered in the late 2000s, and published in a magazine for the world to see in 2013.

When searching for vehicles to fill up a third line of medium tanks for their game World of Tanks (WoT), video game company Wargaming decided to take a controversial approach for their tier 10 vehicle, mashing up two different K-91 designs.

Background

There were three proposals designed simultaneously by OKB IC SV. Development started after the Council of Ministers of the USSR released decree No.701-277§ on 18th February, 1949, which requested the termination of all development and production of heavy tanks weighing 50 tonnes and above. This allowed OKB IC SV, headed by Anatoly Fedorovich Kravtsev, to design a set of vehicles aiming to take advantage of this opportunity. They were supposed to be lighter than 50 tonnes and be able to replace both existing and future medium and heavy tanks. Lead engineer was I.T. Levinov and the designer was Matyukhin. They designed three vehicles: a classical heavy tank, with a front mounted turret; a rear mounted turret heavy tank featuring an autoloader; and a rear mounted casemate self-propelled gun.

The front-mounted turret K-91 heavy tank.
Source: Technic and Weapons No. 9, 2013, M.V. Pavlov, I.V. Pavlov Domestic armored vehicles of 1945-1965, page 34

Rear-mounted turret K-91 heavy tank, which had an autoloader.
Source: Technic and Weapons No. 9, 2013, M.V. Pavlov, I.V. Pavlov Domestic armored vehicles of 1945-1965, page 35

K-91 SPG, which had a rear-mounted casemate.
Source: Technic and Weapons No. 9, 2013, M.V. Pavlov, I.V. Pavlov Domestic armored vehicles of 1945-1965, page 35

World of Tanks Hybrid

In the summer of 2018, the company Wargaming announced a new line of Soviet medium tanks for their game World of Tanks. It started with the A-43 at tier VI, and moved up to the A-44, Object 416, Object 430 II and finally, at tier X, the K-91. This line was set to have as the main feature rear-mounted turrets. The Object 416 was, in fact, a tank destroyer (also called the SU-100M).

One of the biggest offenses present in this new line is the mashup of the K-91 variants. The vehicle is identical to the first K-91 variant, but has the turret moved to the rear, just like the second K-91 variant. Why this was done is bizarre, as the second K-91 variant would have fit well as the tier X vehicle.

The U.S.S.R. tech tree in WoT, showing the medium tank lines. Note the bottom line that leads to the K-91.
Source: WoT

Video Game vs Reality

World of Tanks provides a short paragraph on the supposed history of their K-91:

“The vehicle was developed by the Design Bureau of the Army Engineering Committee under the supervision of A. F. Kravtsev from March through August 1949. The tank was supposed to position a driver in the fighting compartment, as well as feature a 100 mm gun with an automatic loading system, and coaxial large-caliber machine gun. The plan was to mount the 12-cylinder opposed-piston turbo-diesel engine. The mounting brackets with ski-shaped supports were used as support rollers. Development of the project was discontinued at the blueprints stage in December 1949.”

While the text does not have any particular inaccuracies, it clearly describes the rear-mounted turret K-91 and avoids the fact that the vehicle is a mashup. They do state that the engine was turbocharged, which cannot be verified.

Wargaming’s K-91 mashup.
Source: WoT EU

Wargaming got the details and statistics right for the most part. Since there are very few drawings of the K-91s, and they were never built, it is hard to prove when something is accurate or not.

In-game, the K-91 has a 100 mm D-46T. This is historically accurate. The gun was intended as a replacement for the wartime D-10T. Development of the gun began on 28th May 1948 and two prototypes were ready by 1949. However, the program was canceled that same year. Its ammunition weighed between 16 to 17 kg and had a muzzle velocity of 1,000 m/s. In-game, however, it has a muzzle velocity of 1,700 m/s, and the tank can carry 50 of them. In-game, it has +20° of elevation and -9° of depression. In contrast, the real drawings show that it had +20° of elevation and -3° of depression.

Most of the model is a historically accurate render of the rear turret-mounted K-91 heavy tank. The turret matches the original blueprints, as in it has a conical shape, with a bulge for the driver that sat in the turret, to the right of the gun. The driver had a pivoting driving station, so that he would always face the front of the tank, regardless of the position of the turret. This does pose some mechanical problems, so it is unclear if the turret could fully rotate. This has been replicated in WoT, as the turret can only turn 110° in each direction. The loader is placed right behind the driver. On the left side of the gun is the gunner and the commander. The commander has a small bulge in the turret roof for better vision across the turret. A DShK heavy machine gun is mounted to the right of the gun and on the roof, as per the blueprints of the original K-91 with a frontal mounted turret.

The hull also matches the blueprints of the real K-91, but that with a frontal turret and not the rear-turreted one. A large sprocket drives the tracks, which are guided by a set of skids under the hull. The suspension is unique compared to other Soviet medium and heavy tanks. It features small steel-rimmed wheels, individually sprung by torsion bars. Only the first and last torsion bars have two wheels, with dependent suspension, via a pivoting bogie.

To move the turret to the rear, the designers at Wargaming had to make some slight changes to the hull. Mainly, the entire engine compartment was moved to the front, with a direct connection to the final drive, essentially a swap between the engine and turret.

Rear view of Wargaming’s hybrid.
Source: WoT EU

In terms of propulsion, Wargaming states that it used a V-64 engine outputting 860 hp. While the specific power of the V-64 is unknown, Wargaming’s claim is in the upper limit of what the engine could have given. The V-64 was a 12-cylinder boxer diesel engine. The term boxer comes from the layout of the pistons, which are placed horizontally. This allows for a shorter engine and a lower hull, but the engine is also wider.

The armor was significantly lightened from the real blueprint. In-game, the upper frontal plate is 140 mm compared to 200 mm, while the lower plate is 120 mm in-game versus 150 mm on paper. The turret is 160 mm at the thickest and 40 mm at the thinnest, while on paper it was actually 200 mm all around. This was most likely done to fit the medium tank narrative in the game, but the weight remains at around 45 to 50 tonnes.

Wargaming could have easily added the real K-91 rear turreted heavy tank, instead of the current mashup. While it did have a different hull and turret shape, it was very similar. The main difference was the use of an autoloader for the 100 mm gun. Wargaming already exploits a variety of autoloading systems within their game, and since there is no information on the speed of the autoloader, they could have easily played around with the rate of fire data, for a balanced vehicle in-game. This variant does also have slightly thicker armor, but Wargaming has already taken the freedom to downgrade the armor of the in-game K-91 compared to the real thing.

The historical rear-turreted version of the K-91 had a very peculiar hull shape, with a bullet-like shape when seen from above and no vertical angling. Wargaming completely did away with that, preferring to keep the more conventional hull from the front turreted K-91 proposal.

The K-91 with a rear-mounted turret, cutout view.
Source: Technic and Weapons No. 9, 2013, M.V. Pavlov, I.V. Pavlov Domestic armored vehicles of 1945-1965, page 35

K-91-2

Strangely, Wargaming decided to add the real K-91 frontal mounted turret as a Tier VIII premium medium tank (premium tanks are tanks that can be bought with real money or alternative currency within their game) with a fully rotating turret. Fortunately, it is accurate to the real original design, and it is a good representation of what the real project might have looked like.

One of the real K-91s made their way into the game.
Source: WoT EU

K-91 PT

In March of 2021, Wargaming announced the introduction of the K-91 PT, which is the K-91 SPG variant. The acronym ‘PT’ comes from the romanized version of the Russian word ‘protivotankoviy’, meaning anti-tank. This is not entirely historical, as such vehicles were mostly called SU or SAU, from Russian ‘Samokhodnaya Ustanovka’, essentially meaning self-propelled gun.

The K-91 PT, with some bizarre additions, such as a superstructure-mounted machine gun.
Source: The Daily Bounce

Conclusion

While it is amongst one of the least offensive fake tanks in World of Tanks, the version of the K-91 in-game is still a fake that could have been relatively easily avoided if they just used the second historical K-91 version. Other than that, Wargaming kept the vehicle fairly historically accurate, with the exception of removing large amounts of its armor to make it a medium tank.

Reproduction of the K-91 fake tank in WoT by Pavel Alexe.

K-91 Fake tank specifications
Total Weight, Battle Ready	45 to 50 tonnes
Crew	4 (Commander, Gunner, Driver, and Loader)
Propulsion	V-64 engine, 860 hp
Speed	ca 50 km/h
Armament	100 D-64T
Armor	200 mm frontal turret, 140 mm turret cheeks 140 mm UFP 60 mm hull sides

Sources

Technic and Weapons No. 9, 2013, M.V. Pavlov, I.V. Pavlov Domestic armored vehicles of 1945-1965
Yuri Pasholok on the Soviet STG – Status Report (ritastatusreport.live)
https://military.wikireading.ru/56371
K-91 – World of Tanks – tanks.gg
K-91 – Global wiki. Wargaming.net

Cold War Soviet Prototypes

K-91 SPG

Illustration of the K-91 SPG, speculating how it might have looked like. By Pavel Alexe, funded through our Patreon.

Soviet Union (1949)
Heavy Self-Propelled Gun – Blueprints Only

Many heavy Soviet self-propelled guns (SPGs) were based, in some form or another, on a heavy tank. This format was used extensively during the Second World War and became standard post-war. Any heavy tank would serve as the chassis for an SPG as well. So naturally, when all heavy tanks weighing 50 tonnes and more were cancelled in early 1949, many SPGs were ended as well, like the case of the IS-7 and Objects 261 to 263. But this cancellation made space for new, lighter, heavy tanks and SPGs, like the K-91 tanks.

Development

The Council of Ministers of the USSR released decree No.701-277§ on 18th February 1949, ordering that all heavy tanks weighing over 50 tonnes were to be canceled. This gave an opportunity to the Design Bureau of the Engineering Committee of the Armed Forces (OKB IC SV), led by Anatoly Fedorovich Kravtsev, to develop three vehicles – two heavy tanks and an SPG. The vehicles were supposed to replace both heavy and medium tanks, and offer a good platform for an SPG.

The first K-91 proposal, with a frontal mounted turret and engine at the rear.
Source: Technic and Weapons No. 9, 2013, M.V. Pavlov, I.V. Pavlov Domestic armored vehicles of 1945-1965, page 34

Design

The K-91 SPG was largely based on the K-91 heavy tank with a frontal mounted turret. The hull remained almost unchanged, with the exception of the rear, which had to be altered to fit the rear mounted casemate. This was made out of eight thick welded armor plates, heavily angled from all sides to increase armor effectiveness. The main 100 mm gun was fixed into this casemate and had limited traverse. Like on the previous K-91 heavy tanks, the driver was not situated in the hull but moved up into the casemate. The casemate was mounted to the rear of the vehicle to minimize gun overhang and make the vehicle more maneuverable in city streets or forests. However, such a layout had proven to be faulty before as the heat from the engine could damage the barrel or distort the view through the gun sight.

Curiously, the design is very similar to Shashmurin’s IS-2 based SPG and also the much later Object 268 versions 2 and 4. Shashmurin most likely never had any involvement in a OKB IC SV vehicle, and he was generally a rival, as he worked at Chelyabinsk.

Equally bizarre, when the K-91 SPG was introduced into the game World of Tanks, it was named K-91 PT. The acronym ‘PT’ comes from the romanized Russian word ‘protivotankoviy’, meaning anti-tank. This is not entirely historical, as such vehicles were mostly called SU or SAU, from the Russian ‘Samokhodnaya Ustanovka’, essentially meaning self-propelled gun.

Side view of the K-91 SPG
Source: Technic and Weapons No. 9, 2013, M.V. Pavlov, I.V. Pavlov Domestic armored vehicles of 1945-1965, page 35

Crew

The SPG had a crew of 4: commander, gunner, driver, and loader. They were all seated in the casemate.

The gunner sat to the left of the gun. He had controls over the main armament and possibly the secondary coaxial machine gun, if there was any. For vision, he could only use his main gun sight. The commander was seated behind him, albeit higher up. He had a small protrusion from the casemate roof, just big enough to fit the top of his head. There, the single periscope was mounted. Although it was placed quite high up, a single periscope offers atrocious visibility, especially for a vehicle that lacks a turret. It is unclear if it could rotate or not. The commander was likely also in charge of the AA 12.7 mm DShK machine gun. It was mounted on a swivel pintle mount, like on the IS-3 and IS-4. The commander could exit and enter through his small dome, which had a hatch. It is unclear if the gunner also used this hatch or if he had his own.

On the right side of the gun sat the driver. He was also seated quite high up and had his own little protrusion with a hatch, but smaller than the commander’s, which also had a single periscope. The driver could enter and exit via this hatch. Behind the driver, but lower into the body of the vehicle, behind the gun breech, was the seat of the loader. He had full access to the ammunition stored on the right side of the vehicle but had to stand up or get help from the commander when hauling shells from the left side.

Rear cutout view of the K-91 SPG. Note the layout of the engine and ammunition.

Armament

The main armament of the K-91 vehicles was to be a 100 mm D-46T. The development of this gun started on 28th May 1948, and two prototypes were built in 1949 at Factory No.9. It was meant to replace the wartime D-10T gun, but the entire project was canceled shortly after. The ammunition consisted of a single piece, weighing 16 to 17 kg, with a muzzle velocity of 1,000 m/s.

This was the same gun used on the heavy tanks, so the SPG variant did not offer a large advantage over the heavy tanks, one of which was autoloaded and both of which had turrets. There could have been a difference in ammunition loadout, but neither the gun nor the vehicles got far enough in development for this to be a serious issue. Rounds were placed vertically across the side and rear fighting compartment walls, and several stowed horizontally in the hull. The gun was enclosed in a limited traverse mount. It had +20° of elevation and -3° of depression. Horizontal gun traverse is unknown, but judging by the space inside the fighting compartment, around 10° in both directions seems plausible.

Two secondary armaments were probably used, a pivoting pintle-mounted AA 12.7 mm DShK machine gun, and potentially a coaxially mounted DShK as well.

Propulsion

The powerplant of the vehicle was to be a V-64 12 cylinder boxer diesel engine mounted in the front of the hull. In front of it were the transmission and final drives coupled to the large frontal drive sprockets. Boxer engines feature horizontally mounted pistons acting against each other on a crankshaft in the middle. This allows for far shorter engines, but also much wider compared to the usual in-line or V-shaped engines.

Armor

Being based on the K-91 heavy tank, the armor was very good. The upper frontal plate was 200 mm thick, angled at 45°, The lower frontal plate was 150 mm angled at 50°. The side armor was flat and 150 mm thick. The front of the casemate armor was 200 mm thick on the front (60° angle) and cheeks. The side was 120 mm, angled at 60°. The rear was around 100 mm thick, also angled at 60°.

Conclusion

Unless some drastic changes were made to the ammunition or main armament, the K-91 SPG was made obsolete by the other K-91 heavy tanks. The entire K-91 program proved to be unsuccessful and was canceled in December 1949 as the vehicles were deemed to not bring a big advantage over existing medium and heavy tanks.

Object 268 Version 4, on December 18, 1952.

After the end of developments of IS-7 and other heavy tanks, and SPGs based on them, heavy SPG development stopped in the USSR. The concept would be revived, unsuccessfully, for the last time in the 1950s, with the Object 268 program, of which, versions 2 and 4 were very similar to the K-91 SPG.

Illustration of the K-91 SPG, speculating how it might have looked like. By Pavel Alexe, funded through our Patreon.

K-91 SPG specifications
Dimensions (L-W-H) in mm	8,780 (6,570 w/o barrel) x 3,340 x 2,200
Total Weight, Battle Ready	circa 49 tonnes
Crew	4- commander, gunner, driver, loader
Propulsion	V-64 boxer 12-cylinder diesel, est.700-800 hp
Armament	100 mm D-46T co-axial 12.7mm DShK AA 12.7 mm DShK
Armor	200 mm front casemate 120 mm side casemate 200 mm UFP 150 mm LFP, cheeks, side
Total Production	None; paper design only

T-72 Ural-1 in Romanian Service

IS-M (Shashmurin)

KV-4 (Object 224) K.T.T.

KV-4 (Object 224) Kresavsky

KV-4 (Object 224) Tseits

TMA-83 and TMA-79

KV-4 (Object 224) Mikhailov

TAR-76

KV-4 (Object 224) Fedorenko

KV-4 (Object 224) Shashmurin

4K51 Rubezh in Romanian Service

KV-4 (Object 224) Dukhov

7.5 cm SPG (Soviet Hetzer Starr)

Object 718

Object 705 (Tank-705)

Geschützwagen E 100 (Fake Tank)

Object 715

Dacia Duster Army Technology Demonstrator

K-91 World of Tanks Fake Version

K-91 SPG

Socialist Republic of Romania/Romania (1978-2005) Main Battle Tank – 31 Purchased from USSR

Background

T-72 Ural-1

Operation – the 1st Tank Regiment “Vlad Țepeș”

T-72 at the Revolution – Petty Combat

Post-1989 & Dissolution

114th Tank Battalion “Petru Cercel”

TR-125 (P-125)

Type 64

Conclusion

T-72 Ural-1 in Romanian service specifications

Sources

Soviet Union (1944) Heavy Tank – Drawings Only

Shashmurin and the IS

Improving the IS-2

Design

Powerplant

Suspension

Crew

Armament

Armor

Variants

Return to Leningrad and Further Developments

Conclusion

IS-M specifications

Sources:

Soviet Union (1941) Super Heavy Tank – Blueprints Only

Development

The Designers

Design

Crew

Armor

Armament

Misinterpretation

KV-4 K.T.T. specifications

Soviet Union (1941) Super Heavy Tank – Blueprints Only

Development

M.I. Kresavsky

Design

Crew

Armor

Armament

Dinosaur Extinction

Conclusion

KV-4 Kresavsky Specifications

Sources

Soviet Union (1941) Super Heavy Tank – Blueprints Only

Development

N.V. Tseits

Design

Crew

Armor

Armament

KV-5

Conclusion

KV-4 Tseits Specifications

Sources

Socialist Republic of Romania (1984-1990) Medium Artillery Tractor – 200+ Built

Development

TMA-79

Socialist Republic of Romania/Romania (1978-2005)
Main Battle Tank – 31 Purchased from USSR

Soviet Union (1944)
Heavy Tank – Drawings Only

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

Socialist Republic of Romania (1984-1990)
Medium Artillery Tractor – 200+ Built

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

Socialist Republic of Romania/Romania (1977-2005)
Light Artillery Tractor – Around 100 Built

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

Soviet Union (1941)
Super Heavy Tank – Blueprints Only

Socialist Republic of Romania/Romania (1987-2024)
Anti-Ship Coastal Defense Missile System – 4 Purchased