Kirov Factory Prototypes, March 1941

"Report on the progress of experimental tank armament work from February 20th to March 20th, 1941

Object 220 KV-4 100 mm

The experimental prototype is awaiting the arrival of the V-5 engine from the subcontractor factory. Assembly of the second prototype has not started due to a lack of finished parts. The factory already began producing parts for the second prototype. The parts are in the initial stages of mechanical production. Since the plants are highly loaded with mass production parts, it is likely that the full set of parts for the prototype will not be finished in March. The turret for the second prototype is currently at factory #92, where designers from both factories are working on installation of the gun and combat equipment.

Object 221

The hull has been at the Kirov factory awaiting assembly since February 10th, 1941. Assembly has stalled due to a lack of finished parts. The factory is producing parts in parallel with parts for the Object 220. The turret was sent to factory #92 to install armament.

SPG, Object 212

The hull arrived at the factory on March 5th and is awaiting assembly. Assembly cannot start due to a lack of finished parts. Parts are being produced in the same batch as parts for Objects 220 and 221. 

Object 150 KV-3 90 mm

No changes. See report from February 20th, 1941

Object 218 Electric mine clearing tank

The special generator and vacuum tubes have been received. The wooden model is being built. Blueprints for equipment installation are complete and will be adapted on the model. The model will be ready by March 30th, 1941.

Object T-50

The main friction clutch was repaired and installed without a vibration damper on March 11th. On March 12th, the tank was taken for a 120 km test run without a main friction clutch vibration damper. On March 13th, the tank was taken for another 50 km test run, during which the engine water hose burst. It was impossible to replace in the field due to a lack of access to it. The fuel tank and radiator grilles had to be removed to access the hose.

On March 14th, 1941, after driving 200 km without a vibration damper, the following accident occurred: the rivets holding the cooling fan burst and its blades broke off. The fan cannot be repaired. The tank was sent to be repaired. On March 18th, a new friction clutch fan with a vibration damper was installed. but it broke the first time the engine was started. The tank remained in repairs from March 16th to March 19th. When the tracks were examined, cracks were found in 60-65% of the track links. It must be noted that the tank was only driven on a paved highway. When driving on a stone highway, the track links will crack even more. Their robustness is insufficient.

The hull for the second prototype is complete, but has not arrived at the Kirov factory. The following parts are needed to assemble it: road wheels, return rollers, track tightening mechanism, drive sprocket, idler, suspension arms. The gearbox, final drives, main and side friction clutches, are being assembled. 

SKB-2 made the following decisions regarding the second prototype, proposed by Military Acceptance: