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.
–Dear reader: A more detailed development analysis of the KV-4 program can be found in the KV-4 Dukhov article—
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)
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).
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.
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 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.
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.
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”.
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.
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|
|Armament||107 mm ZiS-6 (F-42) main cannon (112 or 102 rounds)
76 mm F-11 secondary cannon (120 rounds)
2x DT machine gun (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|
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