"Approximate calculations
Increase in mass of the T-43 tank as a result of new tactical-technical requirements
The main changes in the tactical-technical requirements that will result in an increase in mass are:
- Increase in the front armour from 75 to 90 mm
- Increase of the turret ring from 1600 to 1700 mm
- Increase of the front turret armour from 90 to 110 mm
- Decrease of the ground pressure from 0.93 to 0.8 kg/cm²
Main changes in tactical-technical requirements that will result in a decrease in mass are:
- Decrease of the rear armour from 75 to 60 mm
- Decrease of the roof armour from 30 to 20 mm
- Decrease of the rear floor from 30 to 20 mm
- Increasing the the front armour from 75 to 90 mm: 196 kg
- Increasing the turret ring from 1600 to 1700 mm:
In the worst case, this will result in: - Increase in the length of the hull by 100 mm: 174 kg
- Increase in the width of the hull by 100 mm:
- The width of the hull may be increased only in the upper part. In that case, the increase in mass will be 184 kg.
- In case the entire hull is widened, the additional weight increase as a result of widening the floor will be 95 kg.
- Increase of the volume of the turret: 170 kg
- Increasing the front turret armour from 90 to 110 mm: 135 kg
- Decrease of the ground pressure from 0.93 to 0.8 kg/cm²:
In the current T-43 variant the ground pressure is 0.93 kg/cm² at a weight of 34.1 tons and contact surface of 36,660 cm².
The new characteristics dictate that the ground pressure should be 0.8 kg/cm². At a mass of 35 tons the contact surface should be 43,750 cm², an increase of 20%.
If 5% is obtained by lengthening the contact surface and 15% by widening the tracks, then the increase in mass will be 375 kg given 2500 kg of total track weight. - Decrease in the rear armour from 75 to 60 mm: 139 kg
- Decrease of the roof armour from 30 to 20 mm: 236 kg
- Decrease of the rear floor from 30 to 20 mm: 274 kg
The total increase in mass of the T-43 tank in satisfying the tactical-technical requirements will be 680 kg.
Assistant Chief of the 6th Department of the GBTU Tank Directorate, Engineer-Captain Rozengard
September 29th, 1943"