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WW2 Soviet KV-4

KV-4 (Object 224) Fedorenko

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 Drawings 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 DT
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
– 3x 7.62 DS-39
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 DS-39
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 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
95 8.52
4.00
3.25
107 mm ZiS-6
45 mm 20-K
6 35 130 mm 2000
5 KV-4 Shashmurin 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 DT machine gun (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 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 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 DT machine guns
6 39 km/h Front: 125 mm 500
7 Bykov 98.6 9.5
4.03
3.65
107 mm ZiS-6
45 mm 20-K
DS-39 machine gun
8 36 km/h Front 130 mm 500
7 Kalivod 500
N/A Fedorenko KV-4 98.65 8.10
4.03
3.70
107 mm ZiS-6
45 mm M.1938
3x 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 DT machine gun
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 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 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 Unkown KV-4
N/A Unkown 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 dual 45 mm ones) 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 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

2 replies on “KV-4 (Object 224) Fedorenko”

That is one wild design. Was the commander’s turret a true ball turret (like the Kugelblitz) or merely hemispherical (like the Fiat 2000)?

I can see the 45mm as a reason to reject the design. The obvious task overloading of the commander was one reason, but the 45mm was supposed to function as a “spotting rifle” for the 107mm. It couldn’t do that if it was in that turret.

Also, as a suggestion could you consider adding a standard human silhouette in the tank illustrations to provide a sense of scale?

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