Future of Soviet Tanks

"February 21st, 1938

To People's Commissar of Defense, Marshal of the Soviet Union, comrade Voroshilov

...

Using existing tanks in the Red Army

1. Existing 862 T-18 tanks should be used as mobile anti-tank guns in fortified regions in the event that modernization results in satisfactory results. Modernization work is currently being performed. If the modernization is unsuccessful, the T-18s should be removed from service and melted down. There are no spare parts for the T-18, and they are not being produced.
2. Use 2690 existing T-27 tankettes (presently removed from production) as communications vehicles in rifle divisions and fortified regions by independent companies/battalions.
3. Use 3851 T-37 and T-38 tanks (presently removed from production) in the Supreme Command reserve, forming special units for capturing footholds across rivers. Do not produce T-37 and T-38 tanks in peace time, only spare parts for them. Industry should be prepared to produce T-38 tanks during war until such a time as an improved amphibious tank with completely bulletproof armour is introduced.
4. 6748 T-26 tanks, as the main type of infantry support tank (the main type of tracked tank), should be used for combined arms warfare alongside infantry. Continue production of the T-26 and spare parts, improve the T-26 design under the condition of parts compatibility with components and assemblies for all existing tanks. Install a stronger engine and suspension (work is currently underway).
   The type of tank currently ordered for production at STZ by order #49ss that is supposed to replace the T-26 tank does not satisfy the NKO's requirements and will only introduce a new tank into the RKKA that does not significantly differ in quality from the T-26 tank. Do not introduce a new tank into service and stop work on this tank at STZ. Retain the mobilization plan for T-26 tanks at STZ.
5. BT tanks: 618 BT-2, 1841 BT-5, and 2346 BT-7 (the main type of convertible drive tank) are designed for either combined arms or independent strikes in support of mobile types of forces. Production of BT tanks and spare parts should continue, with improvements such as a diesel engine and new suspension introduced contingent on compatibility, until a superior convertible drive tank with 6 powered wheels and a diesel engine is adopted into service.
6. 262 T-28 tanks and 41 T-35 tanks should be used in the Supreme Command reserve. The T-28 and T-35 tanks do not protect the crew and vitally important parts of the vehicle from 37 mm armour piercing shells starting with 1000 meters. These tanks can be knocked out before they open fire.
   The task of improving the armour of the T-35 from 20 to 30 mm as ordered by #94ss does not solve the issue of proofing the tank against AT guns, as this tank would be vulnerable to the 45 mm gun from 2000 meters. Increasing the armour to 30 mm on the T-35 would require designing a whole new tank and would not solve the issue of making the tank impenetrable. We need an AT gun destroyer with armour that can protect from 47 mm guns at all ranges.
   The T-28 and T-35 tanks do not meet requirements for fortification breakthrough tanks, especially in combat with AT guns. The T-28 cannot fight tanks. It is necessary to produce one tracked breakthrough/AT gun destroyer tank with 50-55 mm of armour. This tank would be able to destroy anti-tank guns and penetrate fortified regions.
   Until such a tank is adopted into service, continue production of T-28 and T-35 tanks, and continue improving them contingent on parts compatibility.
   Cease development of a T-35 tank with 30 mm of armour and a 1000 hp engine ordered by #94ss.
   Decree #94ss also orders the T-29 tank to replace the T-28 tank. The T-29 has armour vulnerable to the 45 mm gun, same as the T-28 and T-35. It is also nonsensical to have convertible drive for this tank. I deem it necessary to cease work on this tank.

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ABTU Chief, Corps Commander Pavlov

ABTU Military Commissar, Brigade Engineer Alliluyev"

RGVA 4-19-55 pp.1-9