Monday, 27 April 2020

End of the Superheavies

"I order:
  1. My deputy, Chief of the Main Tank Directorate, comrade Maksarev, and Director of the Kirov factory in Chelyabinsk, comrade Zaltsmann:
    1. Cease further production of the IS-4.
    2. Correct defects discovered in the design of the IS-4 listed in attachment 1, then transfer all technical documentation and blueprints for the IS-4 to the mobilization reserve.
    3. Present 12 IS-4 tanks for trials to the Ministry of the Armed Forces of the USSR by May 1st, 1949, with defects corrected in accordance with the decree issued by the Council of Ministers. 2 tanks will be put through 1000 km driving trials, 10 tanks will be put through army trials according to a program approved by the Minister of the Armed Forces of the USSR.
    4. Correct defects on other tanks, present at both the factory and in the armed forces, with changes introduced as a result of the trials before January 1st, 1950.
  2. Director of the Kirov factory in Chelyabinsk, comrade Zaltsmann, must deliver 30 IS-4 tanks with defects listed in attachment #1 resolved in 1949. 
  3. My deputies, comrades Maksarev and Lebedev, and the director of the Kirov factory in Leningrad, comrade Suvorov, and chief designer of the factory comrade Kotin must cease all further design work on the IS-7 tank and transfer all design documents, blueprints, and manufactured tools to the mobilization reserve.
  4. My deputies, comrades Maksarev and Lebedev, and the director of the Kirov factory in Chelyabinsk, comrade Zaltsmann, and chief designer of the factory comrade Kotin must:
    1. Begin development of a new heavy tank according to attached tactical-technical requirements (attachment #2) weighing no more than 50 tons, with the components of the IS-4 tank and the armour layout and hull design of the IS-3 tank no later than February 21st of this year.
    2. Produce, put through factory trials, and then present to the Ministry of the Armed Forces 3 heavy tanks in August of 1949 and 10 in September of 1949 for military trials.
      Comrades Zaltsmann and Kotin must present a list of personnel of the VNII-100 and Kirov factory in Leningrad that will be working on this tank for approval."
"Attachment #2 to order of the Ministry of Transport Machinebuilding #69ss issued on February 19th, 1949

Tactical-technical characteristics of a new heavy tank
(Main characteristics)
  1. Full combat weight: 50 tons
  2. Crew: 4
  3. Armament: 
    1. 122 mm D-25 gun
      1. Angle of elevation: +17 +/- 1 degrees
      2. Angle of depression: -3 +/- 0.5 degrees
      3. Horizontal range: 360 degrees
    2. 1 coaxial 12.7 mm DShK machine gun
    3. 1 AA 12.7 mm DShK machine gun
  4. Ammunition capacity: same as the IS-4 tank
  5. Armour: the armour of the hull and turret should offer no less resistance to shells than the armour of the IS-3 tank. In cases where a continuous curved side is used, the thickness can be set at 80 mm.
  6. The speed of the tank should be no less than the speed of the IS-4.
  7. Ground pressure: 0.77-0.8 kg/cm²
  8. Internal fuel tank capacity: 425-450 L
  9. External fuel tank capacity: 300 L
  10. Total oil tank capacity (internal): 85 L
  11. Aiming mechanisms:
    1. Vertical: hand operated
    2. Horizontal: hand operated using a smooth electric traverse drive from the IS-4
  12. Transmission: mechanical planetary gearbox, planetary final drive
  13. Engine: diesel motor with centrifugal supercharger, service power 650 hp
  14. Power to weight ratio: 14 hp/ton
  15. Running gear:
    1. Individual torsion bar suspension
    2. Fine link track
  16. Communications:
    1. External communications: 10 RT radio
    2. Internal communications: TPU-47 intercom
  17. Tank warranty period: 2000 km
    Engine warranty period: 200 hours runtime in the tank
Notes:
  1. Final tactical-technical characteristics will be determined after obtaining results of the military trials.
  2. The weight of the tank does not include smoke bombs, unditching log, and tarp."

2 comments: