"January 7th, 1943
In October and November of 1942 factory #100 developed and built a planetary turning mechanism designed by Engineer Lieutenant-Colonel A.I. Blagonravov. The report on the trials performed in the KV-1S tank is attached, we ask you to review it.
Presently, the tank was driven for 1085 km, 135 km of which were used for towing trials. The tank with a planetary turning mechanism once towed two tanks weighing 75 tons altogether without much effort.
The planetary turning mechanism is a new step in domestic tank building. Trials showed that the planetary turning mechanism has the following advantages over friction clutches:
- Better off-road maneuverability
- 25-30% higher average movement speed
- Improved mobility
- Reduced effort to steer (12-15 kg vs 40-50 kg)
- The service life of the engine, gearbox, and main clutch are increased
- The brake life is increased
- The fuel economy is improved
We consider it necessary to recommend this mechanism for mass production and immediately produce a pilot batch to test in combat conditions.
With the exception of adapters that connect it with the gearbox and final drive, the planetary turning mechanism is universal for both the KV-1S and T-34.
Blueprints for the planetary turning mechanism with corrections made as a result of the trials are ready. Presently the factory is working on blueprints for mass production of a planetary turning mechanism for the T-34.
Chief engineer of factory #100, Maydelman"
CAMD RF F.38 Op.11355 D.1377 L.56
Printed in Glavnoye Bronetankovoye Upravleniye Lyudi, Sobytiya, Fakty v dokumentakh, 1943-1944 p.35