A review of the design documentation and model were scheduled for January 3, 1943, by decision of Col. Gen. of Artillery Yakovlev, Chief of the Main Artillery Directorate; Zaltsman, People’s Commissar of the Tank Industry; and Ustinov, People’s Commissar of Arms. It took place at the Chelyabinsk Kirov Factory, and it went beyond a simple finding based on the model to involve competition with projects proposed by the Kirov Factory’s design bureau. Competition to the Sverdlovsk SP gun emerged from Chelyabinsk because the ZIK-20 design was delayed and collaboration between the two factories was lacking.
CHAPTER 6.
Birth of the Zveroboy—the “Beast Killer”
Just when the Chelyabinsk Kirov Factory began working on a heavy SP gun is not known for certain. All we can be certain of is that the Kirov Factory did not originate the design of the ZIK-20’s competitor. Moreover, no matter what project was placed in service, it would have to be produced in Chelyabinsk. The originator of work on the heavy SP gun at the Chelyabinsk Kirov Factory is clear from Factory No. 100’s report covering the period from September 15 to October 1, 1942:
The KV-7 tank
The tank with twin artillery systems has been rejected. The GAU suggested that the Kirov Factory mount a single ML-20 artillery system on this vehicle. The system has arrived at Factory No. 100. The designers are preparing drawings for this installation, after which they will begin constructing a wooden model for presentation to the GAU commission.{1}
L. S. Troyanov headed up design of the SP gun. Lev Sergeyevich was the most experienced Soviet designer of all those working on self-propelled artillery. He began with the SU-5, which was based on the T-26; then came the SU-14, the T-100Y, and the T-100Z. It should be noted that Troyanov’s initial development was not an analog of the ZIK-20. According to N. F. Shashmurin’s memoir, the initial SP gun concept was faithful to the GAU’s requirement for a “bunker buster based on a chassis incorporating assemblies from the KV tank:
Concerning development of the SU-152. It mattered which chassis we used for the task. Our team was joined by Engineer L. S. Troyanov, who produced a conceptual layout on a chassis with eight pairs of road wheels and used components from the KV-1S tank.
The year 1942 was drawing to a close. Clearly, that design solution was sheer nonsense. The only solution we liked was one that retained the KV-1S chassis. Kotin came to my office and drew a picture—a 152 mm gun mounted on a KV-1S. Instead of a turret, it had a KV-7-type superstructure. That, of course, was the only proper solution. He gave us an assignment: “Determine the feasibility of that option by 3:00 AM.” He left a sketch of the gun that G. N. Rybin had brought him from F. F. Petrov. We had a layout ready by morning. The designers were N. T. Fedorchuk and M. I. Zeltser. We ended up with a severely overloaded front suspension and a gun that stuck out too far in front. No other ideas came out of a meeting of the lead designers. The main burden of fulfilling this task fell on the team led by V. I. Tarotko and the artillerymen under F. F. Petrov. The KV-1S vehicle and primary production were retained. The total amount of work involved in designing and manufacturing the SU-152 prototype wasn’t excessive, and it was ready a month later.
The documentation largely bears out Shashmurin’s description. Unfortunately, little correspondence remains from this period (November–December 1942). It is possible that some documents, including Troyanov’s initial design, have been retained in GAU files that have yet to be declassified. Incidentally, Shashmurin clearly understated Troyanov’s role in the project: he is listed as “Senior Project Engineer” on the system drawings. The 1:10 scale wooden model and the design documentation for the SP gun were produced towards the end of December 1942. The project was assigned the designation KV-14, and the drawings were given the number 236 (in the summer of 1943, the project began being called Object 236). Correspondence dating from early 1943 also occasionally included references to the designation SU-14.
As mentioned previously, the SP gun models were scheduled to be displayed on January 3, 1943. A. A. Goreglyad and Zh. Ya. Kotin (of the People’s Commissariat of the Tank Industry) and P. F. Solomonov (of the Main Artillery Directorate) were authorized to evaluate the projects. It is interesting that the Kirov Factory’s SKB-2 submitted not one project, but two, each based on a different hull. The following conclusions were drawn from the examination of the projects:
1) The project that Factory No. 9 submitted for review was more complete (to include engineering drawings) than the Kirov Factory project.
2) Factory No. 9’s project required significant modification of the 152 mm gun-howitzer model 1937 (removal of the muzzle brake, a new recoil mechanism, etc.), which was inconsistent with GAU’s operational requirement.
3) The weight of the SP gun designed by Factory No. 9 has increased to 47.5–48 tonnes, and it is larger.
4) The correction of the above-listed deficiencies (paragraphs 2 and 3) required major modifications and revision of the engineering drawings of both the hull and the system.
5) Engineering drawings have been only partially completed for the Kirov Factory’s two versions of its project, and some assemblies (e.g., the frame, the trunnion ring, and the elevation mechanism) required significant modification. For example, the elevation mechanism was taken from the ZIS-5 and did not meet the strength requirements.
6) The Kirov Factory’s first version (which lengthens the hull by 450 mm) caused problems with full-scale production because its side plates could not be manufactured on Factory No. 200’s unit-type machine tools. In addition, the placement of the three front road wheels (which increased the spacing between them) was controversial because it reduced the vehicle’s mobility, especially in swampy terrain and during the spring and fall thaws.
7) The Kirov Factory’s second version introduced the fewest modifications in full-scale artillery and tank production and was sensible in terms of its shape, fighting compartment layout, weight, and dimensions, but it required a large number of drawings to be revised.
The Commission concluded that work on the Kirov Factory’s second version should proceed, and that engineering drawings should be prepared and checked by constructing a wooden mockup.{2}
Needless to say, Petrov was very upset by this outcome. After Factory No. 8 was split in two, the main task of Petrov’s design bureau was development of tank and howitzer systems, and the ZIK-20 became something of a burden. In addition, as already mentioned, the system was going to be produced in Chelyabinsk anyway. Even after the KV-14 project won out, Petrov’s role in the SP gun did not diminish greatly, because he had developed the ML-20 gun-howitzer that was to be mounted on the Chelyabinsk vehicle. The ML-20 modification minus muzzle brake proposed in the fall of 1942 was more suitable, but at that point it was much more important to have as little impact on the design as possible in order not to delay production of the KV-14.
