Monday 12 March 2018

Prototype Problems

"To the GABTU Tank Directorate
Chief of the 4th Department, Engineer-Major F.A. Nenarokov
Moscow, 2 Red Square, NKO building

RE: work of Savin's group on designing an AA gun for a tank.

The anniversary of our design group is July 3rd. Working alongside you, with joint efforts, we managed to obtain a model of a mount with a cannon and a machinegun by September 8th, 1941.

On September 14th, 1941, we composed a letter for Ya.N. Fedorenko to deliver to the Council of Commissars with a request to build a prototype at the factories of the People's Commissariat of Medium Machinebuilding (including NATI), but the group was moved to factory #174 in Chkalov.

I reported to you in letter #128-14.01-42 on work performed up to January 15th, 1942. Presumably, you are also aware of letters addressed to Major-General Ya.N. Fedorenko (#136-15.01-41) and Major-General B.M. Korobkov (#863-1.7.02-42), as I received letter #709196 written on January 23rd, 1942, from B.M. Korobkov, in response to letter #74 that I sent on January 8th to General I.V. Grymzin.

In short, factory #174 had every opportunity to produce not one, but several variants of mechanisms for the AA gun (we had a ZIK-37 gun in our possession from the Donguzskaya proving grounds), but the factory did not wish to perform this work, despite comrade G.V. Gudkov's interest in the topic.

Chief engineer A.S. Zasovenko, true to himself, did nothing in the span of six months (October-April).

Keeping in mind the NKTP's orders to "adapt the mount to the T-34", my senior engineer-designer I.I. Mozhayev spent three months (February-April) at factory #183 in Nizhniy Tagil. The T-34's turret was heavier than the T-50's, which all of our blueprints were designed around, and the traverse drive had to be redesigned (again, maximizing the number of components already in production). The layout was exactly the same and remained in the same cast production turret.

As a result, we obtained a decent solution, from our point of view, which allowed the gun to be elevated to 60-70 degrees in 1 second and a traverse rate of 30-40 degrees per second. The trigger action is instant, as one cannot hit a dive bomber any other way.

Like everyone, factory #183 had its priorities, work that was vitally important, and the subject of an AA gun was a foreign and unwanted intrusion. We were given no people or materials. The issue became worse when the factory began expediting vehicles known to you.

Presently, we are in our fourth location! We changed places four times in a year! This does not help matters. In addition, at this factory, after 1.5 months of our presence, they had a meeting on May 22nd, threw out our drawing boards, and knocked off all of the equipment we had set up, even through they promised S.A. Ginzburg on May 19th that they would help up and to S.A. Afonin on April 7th that the SPG would be built in metal soon. We were called up, presumably, to design an SPG, but we are building an AA tank. The only thing we could offer was to test the mount on their SPG, with the expectation that it could be used on the T-34 and other vehicles without any changes.

Finally, we could install the ZIK-37 on a T-60 or 70 turret ring (it would be tight for two, but perfect for one, given the rate of fire of the gun and 12 round magazines). They did not wish to accept a light AA tank, and began working on an SPG with the ZIK-37 and five men, like on the special SPG. The amount of road wheels will not allow this with the 950 kg gun, but they do not wish to install the 300 kg gun, since it's our design. Our interests diverged, and they did not give us any people. In the experimental department there are also almost no people.

We were happy when comrade K.M. Vasilevskiy familiarised himself with our work and its results (the PT-12 MShZ device). He made valuable comments, which we immediately implemented.

There are no more locations left in the tank industry. We need a reliable base that would be interested in producing the vehicle, provide independence to the head of the design group without hovering over him. If what I was proposing last year was done, then the vehicle would be in production that year.

Factories #20, #69, and others did their job well. As they do not build tanks, I turn to you. Please put us in contact with a tank repair base that could give us a T-50 or a T-34 chassis. We can find a turret or make our own. There are plenty of bases near Moscow and closer to the front. We can use many parts produced by factory #183 (the list is enclosed). I assure you and High Command that this is the only way it can be done. Financing the group is a waste of time, as the GAU finances SPGs. There are many open spaces in Moscow, for instance at factory #37, NATI, and others. There can be no other way that this vehicle will be built. The group could not work intensively since September, for almost nine months! We could have done a lot of good in this time if we had our own base.

Project and group supervisor I. Savin.
June 26th, 1942"

Yuri Pasholok also provides a blueprint of Savin's turret for the T-34.

CAMD RF 38-11355-668 p. 13


  1. I'm not familiar with the "ZIK-37" gun mentioned here, is it an alternate designation for the Sh-37?

  2. I don't recall seeing a photographs off this tank. Indeed there aren't many photographs of Soviet anti aircraft tanks from WW 2.