We report on the results of testing German and domestic HEAT and subcaliber shells against a T-34 hull and spaced armour plates and on improving protection against these shells. This work was performed by GABTU, TsNII-48, and factory #112.
As a result of the trials, it was determined that:
- T-34 armour is insufficient against HEAT and especially subcaliber shells. The most vulnerable parts of the tank are the sides, the turret, the overtrack hull, and to a degree the rear.
German 50 mm subcaliber shells with a muzzle velocity of 1200 m/s penetrate the side of the tank from 1260 meters, the turret from 690 meters, the overtrack hull from 530 meters, and the rear from 360 meters.
The front is impenetrable, aside from the connecting joint, which can be penetrated from 600 meters.
The German 75 mm HEAT shell can only penetrate the lower hull side, destroying the bottom of the overtrack hull and the suspension.
Additionally, the HEAT shell destroys holders and anything that sticks out when it hits the rear, and can penetrate the roof of the hull if it hits low enough on the turret.
- As a result of trials, it was determined that the best measure against HEAT and subcaliber shells is spaced armour, located 100-600 mm from the main armour. In order to protect against HEAT shells, an iron plate only 4-5 mm thick is enough. To protect against subcaliber ammunition, 16 mm of armour is necessary.
As a result, when the sides of the tank have spaced armour 16 mm thick, the T-34 will be almost completely protected from 50 mm subcaliber and 75 mm HEAT shells from a range of 50-360 meters.
We ask that you let us produce T-34 tanks at factory #112 to test in battle, in two variants:
- First variant: 15-16 mm screens for the upper and lower sides and turret. The mass of the tank will increase by 2622 kg, which will make the tank 1152 kg heavier than a mass produced factory #183 tank.
- Second variant: upper and lower sides with spaced armour 10-15-16 mm thick. The mass will increase by 1833 kg, which will make the tank 363 kg heavier than a mass produced factory #183 tank.
December 7th, 1942
The State Committee of Defence decrees that:
In order to improve protection of tanks from HEAT and subcaliber shells, the following must be done:
1. The People's Commissar of Tank Production (comrade Zaltsmann) and factory #112 director (comrade Rubinchik) must produce 46 T-34 tanks with spaced armour by March 1st, 1943, as a part of the quota for the first quarter of 1943. The variants are as follows.
|Variant||Amount||Tank part||Spaced armour thickness in mm||Space between armour plates in mm|