Friday 10 July 2015

KV on a Diet

"State Committee of Defense
Decree #GOKO-1331ss
February 23rd, 1942, Moscow, Kremlin

On the reduction of KV-1 weight

The State Committee of Defense decrees that:
The NKTP (comrade Malyshev) and director of the Kirov factory comrade Makhonin must produce KV-1 tanks that are 1.3 tons lighter by February 25th, with the following changes:
  1. Removal of additional fuel tanks (580 kg)
  2. Reduction of on-board ammunition storage to 90 shells
  3. Reduction of the on-board parts and tools kit by 200 kg
  4. Use of tracks with teeth on every other track link.
Chair of the State Committee of Defense, I. Stalin."


"State Committee of Defense
Decree #GOKO-1332ss
February 23rd, 1942, Moscow, Kremlin

On the reduction of the thickness of the KV-1 cast turret to 95-100 mm.

The State Committee of Defense decrees that:
The NKTP (comrade Malyshev) and director of the Kirov factory comrade Makhonin must produce KV-1 tanks with a cast turret that is 95-100 mm thick by April 1st, 1942.

Chair of the State Committee of Defense, I. Stalin."


"State Committee of Defense
Decree #GOKO-1334ss
February 23rd, 1942, Moscow, Kremlin

On the production of KV-1 tanks weighing 45-45.5 tons with 650 hp diesel engines.

The State Committee of Defense decrees that:
  1. The NKTP (comrade Malyshev) and director of the Kirov factory comrade Makhonin must begin production of KV-1 tanks weighing 45-45.5 tons with 650 hp diesel engines starting on April 15th, 1942.
  2. The NKTP and Kirov factory are allowed to reduce the weight of the KV-1 by doing the following:
    1. Reduction of the total thickness of tanks with armour screens to 95 mm.
    2. Reduction of removable roof elements, turret roof, and hatches to 30 mm, keeping the average hardness at 3.4-3.8 by the Brinell scale.
    3. Reduction of the rear armour to 60 mm.
    4. Reduction of the rear floor to 20 mm.
  3. The acceptable tolerance of thicknesses for 75 mm plate is between -2 mm to +1 mm, with the appropriate change to technical conditions for armour robustness. Instruct the People's Commissariat of Ferrous Metals to start supplying armour with this tolerance starting on March 10th, 1942.

Chair of the State Committee of Defense, I. Stalin."

    5 comments:

    1. What is the reasoning for this decision ?
      Less fuel ammo and spare parts carried on the tank itself seems to me a heavy price to pay for weight savings.

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      Replies
      1. Klims had problems with mobility mainly because not very suitable gearboxes they had. Overarly the new 5 speed transmision had the biggest effect on increasing mobility. For instance just compare the power to weight ratio of the early KV models that had "terrible mobility" with IS 2 which had quitly good mobility for heavy tank thanks to better transmision. Saving the weight especially by thinning out front armour was bad decision because front armour have small area and dont save too much of weight.

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      2. Even these reductions weren't enough, that's why the KV-1S was made as a temporary step towards getting rid of the KV-1's problems.

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    2. Had serial tanks somewhere thicker armour than that heckneyed 82 mm of turret (mantled or turret mask)? Thanks.

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    3. Damn i feel stupid now i knew about the KV-1S and the gearbox problems but i never put 1 and 1 together.

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