Monday, 28 August 2023

Alternative Heavy Tank

Factory #183 in Kharkov was the center of Soviet heavy tank development in the interwar period. The T-35 powerful (heavy) tank developed in Leningrad by N.V. Barykov was produced here. Production was set up with the participation of I.S. Ber, who was appointed as the head of HPZ (factory #183) Diesel Department design bureau T-35K. Iosif Solomonovich Ber played a key role in the fate of the T-35 tank. It was he who produced the technical documentation for the tank and further development of the design was done under his direction. Work to replace the T-35 moved to Leningrad in 1938 and Ber was promoted to the position of deputy chief of the KB-520 design bureau. Work on heavy tanks in Kharkov ended, but not for long.

I.S. Ber, a key player in the creation of T-35, T-34M, and T-44 tanks.

The Kirov factory in Leningrad became the main location for development and production of heavy tanks by the spring of 1941. The KV-1 heavy tank and the KV-2 assault tank were produced there. Work on the KV-3 tank (the improved T-150) was also conducted here. However, after Soviet intelligence reported that Germany was working on 90 ton tanks, these plans went awry. The name KV-3 was attached to a completely different tank, one that was much heavier and armed with a 107 mm gun. Work on the KV-4 and KV-5 also kicked off. The last heavy tank designed in Kharkov was born in this atmosphere. As a result of a mistake in a report composed at the Mariupol factory it is called A-44 today, but at the time the tank was called T-44.

Initial requirements for the T-44 tank, April 1944. 

Factory #183, the source of almost all available information on the T-44, never called it a heavy tank. However, the purpose of the project that appeared in late March-early April of 1941 was clear. I.S. Ber and KB-520 were aiming for the niche left by the KV-1 and T-150 in addition to their T-34M project. The difference was that Kharkov's candidate had much higher mobility. At a mass of 29-29.5 tons, it had 75 mm thick front armour angled at 60 degrees. This kind of armour would protect from the 88 mm Flak 18 at least at medium distances. The armament was the same as on the T-150: a 76 mm ZIS-5 gun with 3-K ballistics. The top speed on a highway was estimated at 55-60 kph. The tank had the same V-5 engine as the T-150. It worked unreliably on the heavy tank, but the T-44 would be 1.5 times lighter.

This model was shown to Voroshilov.

The situation around the T-150 was the main cause for development of the T-44. The KV-1's replacement was quite unreliable and there were likely concerns that it would never become satisfactory. The constant increase in weight was also impacting its mobility. It seemed that someone up top wanted an alternative that was lighter and more mobile. The issue of building two T-44 prototypes was raised in April of 1941. According to a proposal by the Council of People's Commissars of the USSR and VKP(b), two prototypes were due by October 15th, 1941, and results of the trials must be presented by December 1st. As mentioned above, the situation changed drastically in April. The T-223 tank with a 107 mm ZIS-6 gun replaced the T-150 (or rather the T-222, an improved version of the tank). For a time, development of the KV-1 was not considered at all. This change in the situation affected the T-44.

The lightest variant with a 57 mm ZIS-4 gun.

The reworked project was presented to K.Ye. Voroshilov in April of 1941. Or rather, projects. The division was caused by an alternative to the 76 mm ZIS-5 that appeared in April of 1941. This was the 57 mm ZIS-4 that had identical penetration and a more promising future. The start of work on the KV-3 also did not go unnoticed. KB-520 presented three variants of the T-44 with different armament, armour, and mass. The initial variant was the lightest. Like before, it had a rear fighting compartment. The first proposal had a crew of 4-5 men, now the number increased to strictly 5. Three, including the commander, sat in the turret, which now had a cupola. The hull gunner/radio operator sat behind the driver and the engine compartment was located to their right. The tank previously had two DT machine guns with the option of replacing the hull gun with a flamethrower, now it had six machine guns. Dual DS machine gun mounts were located in the front of the hull, paired with the gun, and in the turret bustle. The commander also had a pair of PPSh submachine guns in his cupola so he didn't feel left out.

The 36 ton tank had two machine guns in every mount.

Various changes introduced into the project increased the tank's mass to 36 tons. This did not affect mobility. The top speed was still expected to be 59 kph. The second variant was almost the same. While the first variant had the 57 mm ZIS-4 gun, the second had the 76 mm ZIS-5. The thickness of the front armour increased to 90 mm and the mass increased to 40 tons. Mobility only increased, as the second variant would be equipped with the V-6 (V-2SN) engine that the KV-3 used. 850 hp provided a powr to weight ratio of 20 hp/ton. The second variant of the T-44 was expected to accelerate to 65 kph.

Cutaway drawing.

Finally, the third variant was clearly aiming to dethrone the KV-3. The fronts of the hull and turret were 120 mm thick. The sides were 100 mm thick. The mass reached 50 tons, which undoubtedly made it a heavy tank. This tank would have the same 107 mm ZIS-6 gun as the KV-3. The turret was altered to accept it and the turret ring diameter increased. Thanks to a rational layout of the fighting compartment, it held 60 fixed rounds for the main gun, 10 more than the KV-3. The tank weighed 18 tons less than its competitor. A top speed of 53 kph was expected, 1.5 times greater than the KV-3. Even if the final product was heavier and slower than planned, it would still be more mobile than the KV-3.

The heaviest variant of the tank with a 107 mm ZIS-6 gun.

Voroshilov approved the project, but the final decision was slightly different. NKSM order #193s issued on May 10th, 1941, in many ways returned the project to its initial state. The armour, mass, and mobility remained the same. The rear machine gun mount was removed. The idea of two machine guns per mount remained, but they were now DTs. The order for two tanks (one with a ZIS-4 and one with a ZIS-5 gun) remained, but later that month the requirement for the ZIS-5 gun was dropped because a gun with the ballistics of the 3-K was no longer considered viable.

Left: requirements for the T-44 issued in May of 1941, right: requirements dated May 1942

Many technical solutions used in the T-44 tank were the same as those used in the improved T-34M. The tanks also shared the same fate. After the start of the war, work first paused and then ended altogether. Nevertheless, the T-34M and T-44 were reborn in the summer of 1942. The T-34M evolved into a new tank called T-43, but the T-44 never moved past technical requirements. A fast heavy tank was now being developed in Chelyabinsk. The T-43 was likely even seen as a replacement for the KV-1 or at least a competitor to the KV-13. Ber never returned to heavy tanks. At that point, he was the deputy chief designer at factory #112, whose priority was the T-34 tank.

Original article by Yuri Pasholok.

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