"Theses of the report by the commander of the Armoured and Mechanized Forces in the Group of Soviet Forces in Germany, Marshal of the Armoured Forces Rotmistrov, titled "Tanks of the Soviet and Foreign Armies Presently, and the Potential of Their Development"
March 24th, 1947
Overall conclusions regarding the tanks of WWII and the potential of its development:
- Due to the thickening of armour and gun calibers, light tanks are departing from the battlefield. The amount of medium and heavy tanks is increasing.
- The protection armour offers is, chiefly, increased by increasing its thickness. 200 mm thick armour will be very common soon. Ground pressure and acceptable width for railroad transport will be the limiting factors in increasing the thickness of the armour any further. In the future, it will be important to change the quality of the armour. Simply increasing the thickness of the armour is a dead end. The protection must be increased not by adding more armour, but by improving its qualities and using composite armour.
- The effectiveness of tank guns grows linearly with the increase of the caliber and barrel length. Guns are designed to fire directly at long ranges (1-2.5 km), which dictates their caliber and muzzle velocity, which also raises the requirements for observation devices.The penetration of guns increases, mostly, by increasing the muzzle velocity and the gun caliber, and the muzzle velocity is increased by lengthening the barrel. It is obvious that increasing muzzle velocity by lengthening the barrel any further is unrealistic. It is possible to improve in this category by creating improved explosive substances and the qualities of the shell itself (mechanical qualities) and the design of the gun barrel.For example, guns with conical 28.20, 42/28, and 75/55 mm barrels appeared, which increased the speed of a subcaliber round to 1200-1400 m/s.To illustrate the impact of a high muzzle velocity and mechanical toughness of the shell on its penetration, it is sufficient to demonstrate this example. Shells for the 90 mm gun of the American T26E4 tank equipped with a tungsten carbide core are capable of penetrating 355 mm of armour from 275 meters.The caliber is also approaching its limit, as increasing the caliber rapidly increases the weight and size of a shell, which means that loading becomes more difficult and less ammunition can be carried.
- The engine group is not mature in the sense of the range of power outputs an reliability. The power output range is a weak point, which slows down the modern development of tanks.
- Observation devices, turret traverse mechanisms, and gun stabilizers demand more attention than they are currently given. Precision and agility of tanks depend primarily on the maturity of these components.
Maximum weight of a heavy tank
Since the main tanks on the battlefield are tanks with powerful armour and armament, it is important to determine the limits of thickening the armour of such a tank. If we postulate that the tank must not be taken apart into pieces and must be transported via railroad without any complications, then the limits of the tank's weight are defined by the acceptable width for railroad transport, ground pressure, and the ratio of the length of the contact surface to its width, which dictates the agility of the tank.
If we assume that long range transport will be achieved by special towed platforms, then the width restriction can be increased, thus increasing the maximum weight of a tank. The thicker the armour, the smaller the dimensions of the engine-transmission group must be. Ultimately, they determine the maximum thickness of the tank's armour. The thicker the armour, the smaller the useful volume inside the tank, and less space is left for the engine and transmission. For a tank with powerful armour, a T-34-like shape is inevitable.
Assuming the maximum acceptable width is 4 meters (such a tank will be transported by towed platforms), the weight of the tank can be increased to 100 tons, and the thickness of the armour to 350-450 mm.
If we build super-powerful tanks with the restriction of the railroad width, then the maximum weight of a tank can be 97 tons.
Given the present methods of tank layouts, the thickness of a tank's armour cannot be more than 350-450 mm if it is to be transported by railroads. It is obvious that even with modern tank guns (100-128 mm in caliber) further increase in muzzle velocity can achieve penetration, if not of the plates themselves, then their joints, from 1.5-2 km. After that, a leap must occur in the quality of armour and guns. It will soon be impossible to simply grow the length of a barrel or the thickness of armour. Quantity must be turned into quality. In the meantime, 300-350 mm thick armour will allow the creation of a first class breakthrough tank in modern conditions."