CAMD RF 38-11355-6
"Minutes of the joint commission for the trials of 700 hp and 850 hp engines, produced by factory #75, and field trials of T-150 and T-220 tanks, produced by the Kirov factory, in which these engines are placed.
- Chief engineer of factory #75, comrade T.P. Chupahin
- Chief of the Kirov factory tank department, comrade A.I. Lantzberg
- From BTU KA
- Military engineer first class, comrade Gluhov
- Military engineer third class, comrade Kaulin
- Military engineer third class, comrade Voroshilov
- The engines were accepted for field trials too soon.
- The engines need factory trials, not field trials.
- In order to swiftly complete the engine corrections, transfer the tanks to the intra-factory commission for factory engine trials.
- The commission for engine trials should include the BTU engineer in charge of the T-150 and T-220.
Finish the trials before
March 10th. The Kirov factory and factory #75 must provide normal conditions for the engines inside the tanks and provide tanks with working engines and cooling systems for field trials by this date."
Looks like they got too hasty. The 850 hp engine didn't get anywhere, but the KV-220 ended up with a V-5 engine turbocharged to 700 hp by April.
CAMD RF 38-11355-6
"To the chief of the 3rd department of the BTU KA, Military Engineer 1st class, comrade Afonin
In addition to the report from April 20th, 1941, I report the following with respect to completed trials:
- By May 4th, 1941, object #220, with additional weight to simulate the weight of a KV-3, endured 967 km worth of trials. Of those, 448 were on a road, and 519 were off-road. The V-5 engine worked for 68 hours and 30 minutes.
- During trials, the following failed:
- Balancer with idler axle: 6
- Lower road wheels: 2.5
- Torsion bars: 1
- Idlers: 2
- In addition to the note from April 20th, the following defects were discovered:
- The 2nd and 4th gear pins in the gearbox were sheared off.
- The eyelet of the main friction clutch was destroyed.
No defects were found in other components of the transmission during technical inspection.
It is necessary to point out that the off-road conditions were especially difficult, and the V-5 700 hp engine only reached second gear. Third gear is only usable on the road or hard ground.
During trials, the following data was obtained:
- Highway fuel efficiency: 2.9-3.2 liters per kilometer"
Sadly, this is the only page of this document that I have, but I think it gets the idea across. Keep in mind that the already portly 62 ton tank was loaded to 70 tons, heavier than any other Soviet tank that was built.