January 26th, 1944
Regarding your inquiry relating to tactical-technical requirements for a light tank, here are the possible changes to requirements:
- The choice of the best position of the transmission and drive sprockets is left up to the discretion of the factory designer. The transmission must be easy to remove, install, and service in the field.
- The maximum speed can be lowered to 42 kph, but the average speed on a dirt road must remain at 30 kph.
- The suspension can be either individual torsion bar or torsion bar with bogeys, under the condition that it remains sufficiently limber and reliable.
- The maximum ground pressure should be no more than 0.65 kg/cm².
- The 60 mm of turret armour specified in the requirements much be rolled and high hardness. In case of cast armour, it must be at least 75 mm thick. The slope of the turret sides should be at least 30 degrees.
- Mounting the gun from the outside allows the replacement of the gun in the field without a high capacity crane.
- Experience in the Patriotic War showed that it is reasonable to have AA machineguns on a tank. I consider that it is necessary to install an AA machinegun on the rotating part of the commander's cupola. I am attaching overall drawings of the M4A2 tank to be used as a reference on how to install an AA machinegun on the roof of a turret.
- Until a planetary transmission is designed, it is acceptable to install a regular mechanical gearbox into the tank with a two-stage planetary turning mechanism.
After the planetary transmission is designed and tested, it should be installed in the tank to replace the regular gearbox and two-stage planetary turning mechanism.
To make decisions regarding the design of gearboxes easier, I refer you to the Baumann institute, which previously worked and is still currently working on such a transmission for heavy and medium tanks.
- The Kirov factory SKB-75 is working on a diesel engine for a light tank. The design will have a significant number of parts in common with the V-2.
- Engine name; V-20
- Number of cylinders: 8
- Angle of cylinders: 90 degrees
Contact the Kirov factory to be informed of the latest developments on the V-20 and to receive full information about the topic.
Chief of the GBTU Tank Directorate, Major-General of the Engineering-Tank service, Afonin
Chief of the 6th Department of the GBTU Tank Directorate, Engineer-Colonel Solinin"