Monday 9 January 2023

Kirov Factory's Light Alternative

The appearance of Zhosef Yakovlevich Kotin as the chief of the Kirov factory's SKB-2 design bureau in 1937 launched a number of interesting processes. Under O.I. Ivanov before him, the bureau sat quietly and worked on ideas that came from the top. There were few original projects, and the ones that were weren't seriously considered. The situation radically changed when Kotin arrived on the scene. A fierce competition broke out with experimental factory #185 that previously held a monopoly. The monopoly on breakthrough tanks was the first to crumble. This was Kotin's achievement, as he created first the SMK-1 then the KV. Factory #185 wanted to build their alternative to the KV with the index 050, but while the KV was accepted into service the 050 was not even built. At this point the experimental factory was reaching the end of its life.

An experimental hull of the T-221, Kirov factory's first support tank.

Factory #185 was also losing territory to factory #174. In 1939-1940, the latter did more than the former achieved in a very long time. This only happened due to the arrival of S.A. Ginzburg at factory #174. Ginzburg had an excellent understanding of a vehicle's lifecycle.

It became clear during the Winter War that the T-26 needed a replacement. Factory #174 received a task to develop a new support tank on February 4th, 1940. The vehicle was indexed T-126. Ginzburg was assigned as the head of the project. Work on analogous tanks began at factory #185 (T-125 led by I.I. Agafonov) and the Kirov factory (T-221 led by A.S. Yermolayev). The T-125 died quickly, but the T-221 had a different fate. Kirov factory developed its project quickly. New tactical-technical requirements appeared on April 29th, 1940, leading to a reworking of the T-221 and T-126. However, work on the T-221 stalled when the Kirov factory was saddled with a large number of new projects. Kotin's team was down, but not out.

Either a predecessor or a contemporary of the T-50.

By the fall of 1940 the SP-126, the new infantry support tank, needed a lot of changes. It turned out that it was too cramped and the mass surpassed the requirements by a few tons (or a whole 4 tons if you measure from the initial requirements). New requirements were also introduced. A three-man turret like on the Pz.Kpfw.III was now needed. Only the driver would sit in the hull. The Committee of Defense within the Council of Commissars issued decree #427ss on November 19th, 1940. The decree instructed factory #174 and the Kirov factory to produce two prototypes each of a new tank. Both tanks had the same index: T-50. The new vehicle was due urgently, by January 15th, 1941. The Kirov factory got a second chance despite clearly being behind in the race with the T-221. The competition between the two factories erupted once more.

The T-50 was originally envisioned like this. The sketch is dated November 19th, 1940.

Kirov factory was still behind when it came to the new tank. Factory #174 already had prototypes of an new support tank that were built and tested. Those tanks had a lot of issues, but they weren't starting from scratch. Meanwhile, even the T-221 was very far from the new tactical-technical requirements. The path towards the factory's own T-50 would be harder.

The second variant of the tank had a cast hull.

Like with the T-221, the T-50 project was led by Yermolayev. Even though it may have seemed that he started from nothing, that was not exactly the case. Documents from N.F. Shashmurin's personal archive show that a light tank indexed K-1 was developed in 1940. This was a 9 ton tank with a low silhouette. The engine and transmission were taken from the T-26. The engine was supercharged. This was clearly a grassroots project since it doesn't show up anywhere in Kirov factory's documents. Nevertheless, it looks very similar to the factory's T-50 tank. Either Shashurin and Yermolayev developed their vehicles in parallel or, as Shashmurin claims, the K-1 grew into the T-50. In either case, Shashmurin had a direct link to the T-50's gearbox.

Model of the tank, December 23rd, 1940.

Kirov factory's SKB-2 prepared two drafts of T-50 variants. Inspection of the Pz.Kpfw.III conducted both at the Kirov factory and factory #174 was taken into account. However, suggestions that the T-50 was a copy of the Pz.Kpfw.III are laughable. The Soviet tanks were only similar to each other. The Kirov factory only borrowed the shape of the turret (typical German "horseshoe"), commander's placement in the cupola, and parts of the gun mount. The Red Army liked the idea of two coaxial machine guns. The T-50 designed at the Kirov factory could aim its machine guns independently from the main gun, just like the German tank. This was not the best idea. Everything else about the tank was original. Even the T-221 contributed very little to the T-50, although there was a direct link. The Kirov factory explored the idea of casting hulls and turrets whole in 1940, which is why one variant of the tank had a cast hull and another had a welded one. The cast variant was quickly dropped since the production methods were not yet worked out.

The two hull machine guns didn't live long.

Work continued on the first variant. The deadlines were tight. Kirov factory order #46 issued on November 15th required the documentation to be complete by December 20th. 100,000 rubles were allocated to the production of a prototype. Kirov and Izhora factories were corresponding frequently. I.M. Zaltsman, the director of the Kirov factory, expedited the work. This had an effect. The Izhora factory received requirements for hulls and turrets for the two prototypes by December 12th. A full set of blueprints for the hull was also received on that day. The characteristics of the vehicle were known by then. It would weigh 14 tons, which was the maximum limit set in the requirements. The tank would be very fast. According to calculations made in mid-December, the tank would reach a speed of 58 kph in 8th gear. This high figure was justified, considering the 300 hp engine and a power to weight ratio of over 20 hp/ton.

The Kirov factory's tank was influenced by German designs, particularly the shape of the turret and dual machine guns.

The two hull machine guns remained when a full scale model was built. These machine guns were placed to the left and right of the driver. A flamethrower developed by factory #174 could be installed instead of the right machine gun, replacing a part of the right side ammunition racks. The driver's station was very well thought out, better than the factory #174 design. Initially it had a T-26 style large folding hatch lid, but it was dropped. In addition to the observation port, the driver had three periscopes. His position protruded from the front of the hull, making a cabin that was easy to work in. The layout of the hull was otherwise similar to the KV-1, which was logical. The hull narrowed towards the rear to save on weight. The original horseshoe shaped radiator was placed between the engine and the gearbox. 

The chassis had many similarities to the KV-1, although there were plenty of original solutions.

The model and its documents were reviewed by a commission from December 23rd to December 28th, 1940. Since Ginzburg was a part of the commission, the tank was at a disadvantage. Ginzburg began his crusade against the tank from the start, during the review, and continued it after. On January 13th, 1941, he wrote an 8 page letter criticizing his competitor's project, suggesting that the projects should be rolled into one. He also composed a 4 page list of drawbacks, although the commission only outlined 8 main issues. Serious omissions included a lack of radio, vulnerable air intakes, external hinges of the hatch flaps, etc. There were 78 individual comments and notes. Nevertheless, the model was approved and permission was given to produce two prototypes.

Some of these solutions would return on the KV-13.

The budget for Kirov factory's light tank was far from light: 3,000,000 rubles in all, of those 900,000 to build prototypes. This was not a low price. Experimental tanks are not cheap, but the tank cost the same as the T-150, and the T-220 only cost 1,200,000 rubles. The biggest issue was not the price, but the timeline. Even if just the first prototype was delivered, the deadlines would not be met. The first hull came from the Izhora factory on January 25th, 1941, and the turret a day later. They had a number of differences from the draft. The mass of the tank decreased to 13.8 tons and the speed increased to 64 kph. The driver lost one of his machine guns, keeping one that could be replaced with a flamethrower. Both the ability to install a flamethrower and the top speed were still theories. As of January 30th, 1941, the first prototype was only awaited by February 6th, and even then this was an optimistic estimate.

Prototype of the tank. The flamethrower port is to the right of the driver's vision port.

Assembly of Kirov factory's first T-50 prototype was finished by February 15th, a month and a half after its competitor. Mobility trials began on the next day, but ended very quickly. The cooling fan broke and its blades shot right into the radiator. The tank was sent to repairs. One could bury Kirov factory's tank there and then, but its competitor was not doing much better. Mobility trials showed a whole series of problems. The trials ended on February 17th with an order to improve the tank. Both T-50s were on even ground, and Kirov factory could make an effort to catch up. There was one nuance: the T-50 was factory #174's only tank, while Kirov factory had the whole KV series to worry about. 

The tank was finished a month and a half after factory #174's entry.

Kirov factory only returned to the subject in March of 1941. The tank completed 6 outings by March 20th, each of which revealed more defects. Some of them were the same as those shown by factory #174's prototype. For instance, 60-65% of the track links had cracks by March 19th. The fan broke twice more and there were issues with the transmission. The second prototype was doing even worse. The hull was finished by March 20th, but not yet delivered to the factory. The first prototype travelled 600 km by April 1st, but as the military representatives noted it spent most of its time undergoing repairs. Work on the tank froze with no activity regarding the first or second prototype recorded by April 20th. Primarily, this was because the Kirov factory was tasked with developing a whole new family of KV tanks, most urgently the KV-3. It's not surprising that factory #174's tank was accepted into service with the Red Army on April 16th, 1941. Sure, the tank was raw, but Ginzburg's team at least tried.

Trials of the tank stalled in March of 1941 when the Kirov factory essentially abandoned the project.

In hindsight, Ginzburg's proposal made in January of 1941 turns from an attempt to get rid of a competitor to something else. The Kirov factory would not have produced their own tank, as there was nowhere to do it and no time to set it up. This way, a number of solutions could have been used on the tank that ended up going into production.

Kirov factory's first prototype didn't go anywhere in May or June. A genius idea of thickening the armour to 60 mm and installing a 76 mm gun (presumably an F-34) cropped up. The top speed of this tank dropped to 40 kph. This "pocket T-34" was rejected as having no merit. Marshal Kulik ordered the reassignment of the experimental T-50 to factory #174 back in May, but this didn't happen. Kirov factory's T-50 was given a new friction clutch in July of 1941 and shipped to the vicinity of Avtovo. This was the end of the tank's combat career, as the Kirov factory was evacuated to Chelyabinsk and the tank went with it. Its final fate is unknown.

The last activity relating to the T-50. It proved that the Kirov factory no longer cared about the T-50.

In the case of the two T-50s, the choice had to be made between a flawed tank and no tank. Picking factory #174's tank was the logical solution from the start. However, Kirov factory's T-50 was not a complete waste of time. If you look at that tank and the KV-13 side by side, you will see many interesting similarities. It turned out that the IS-2, the best Soviet heavy tank of the war, is a descendant of this unsuccessful tank. Nevertheless, Ginzburg had a point, and the tank should have been developed jointly instead of as a competition.

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