Although the tank industry in Czechoslovakia was hit to some extent during World War II, it recovered quickly after the war, and the country recovered a number of armored weapons after the war to repair and reuse it, including dozens of 38t light tanks. As a classic World War II light tank, the chassis of the 38t tank is still considered to have potential for exploitation, so companies such as ČKD have proposed a variety of derivative model development plans.
The TNH 57/900 light tank was one of ČKD's development projects in the late 1940s and one of the most promising models to become a reality, when the Czechoslovak Army had several battalions equipped with 38T tanks, and ČKD itself retained several tanks for research and development.
As a light tank, it was fitted with a 37 mm main gun during World War II, and after the war planned to upgrade its firepower, the options of artillery were the A23 37 mm gun with 19 drums, the A24 47 mm gun with 13 drums, and the A25 57 mm gun with 10 drums, at that time there were also 76.2 mm guns and 105 mm howitzer designs, although they were developed in the direction of tank destroyers and self-propelled howitzers without rotating turrets, and were not standard tanks.
Among them, the most promising is the A25 gun, during World War II, light tank firepower has been greatly upgraded, for example, the M24 "Xiafei" light tank is equipped with a 75 mm gun, the A25 is more balanced in terms of weight, size, power, etc., more suitable for the turret of the 38T tank, the tank name in the 57/900 refers to the caliber of the gun and the initial speed of the muzzle, according to the calculation of its armor-piercing shell at a distance of 1000 meters at 60 ° hit can penetrate 81 mm armor, although it can not compete with the main tank, As a light tank, it is enough, and the artillery has the ability to fire continuously, and 10 shells are enough for the other side to "drink a pot". The tank was expected to carry 50 main gun shells, as well as 3,000 rounds of machine gun ammunition, with a secondary armament of 2 7.92 mm machine guns.
The tank will be equipped with a new turret, and the protection will be strengthened, the front armor of the tank will be increased to 50 mm, the side of 30 mm, the tail of 20 mm, the overall weight is expected to increase to 15 ~ 16 tons, greatly more than the 38t tank of 9.5 tons. Although the turret part has also been upgraded and strengthened, the size of the tank itself limits the pitch movement of the gun, and the pitch range is -5 ° ~ 25 ° according to the design, another saying is -5 ° ~ 20 °.
The increased weight meant that a stronger engine was needed, and ČKD had tested a 220 hp V-diesel engine on a 38T tank, and the engine was already ready for mass production, which could get about 16 hp/ton of unit power if installed, but ČKD was also developing another 250 hp V8 engine that could be calculated to allow the tank to run at a maximum speed of 48 km/h.
Technically speaking, the TNH 57/900 light tank is relatively easy to achieve, at that time Czechoslovakia was also seeking to export armored weapons, but the actual situation was not optimistic, after the end of World War II, the international market was filled with a large number of surplus equipment, buyers have many choices, such as M24; in China, there is skoda company to compete with it, the latter proposed T40, T50 and other designs, although there is no physical object, but in theory the comprehensive strength is more than TNH 57/900.
The deadliest blow came from the outside, czechoslovakia was allowed to produce the T-34-85 medium tank, a move that directly blocked the country's tank development project, because the T-34-85 met the military's demand for light and medium tanks at the same time, without the need for additional equipment development.