The first production model of the series was the BT-7-1, which had an M-17T engine that was capable of propelling it at speeds of up to 72 kilometers per hour. The BT-7 also had a crew of three men, though this late proved to be a severe drawback of the BT-7 because the commander was also required to be the gunner meaning it was far harder to coordinate BT-7s with commanders constantly manning several roles at once.
With a Christie suspension system and a 3 speed forward, 1 speed reverse transmission, the BT-7 was well known for its great mobility and cross country ability. The total weight was around 13,900 kilograms while total length was 5.6 meters. Armor protection was 22 mm at best with 10 mm of armor being far more frequent creating a light sense of protection for the crew at best.
Armament on the BT-7 was a single 45 mm L/46 cannon along with one coaxial DT machine gun and one hull mounted machine gun.[N 2] The vehicle held onboard around 360 liters of fuel for a maximum operational range of around 430 kilometers.
The first variant of the BT-7 (excluding the fact that the BT-7 could be considered a variant itself of the long line of BTs before it) was the BT-7-2 which had the notable feature of dual hatches on the top of the vehicle.[N 3] Furthermore, the hull of the vehicle was given a redesign.
The second variant was the BT-7-1U which was a command tank featuring additional radio equipment as can be expected from such models and a modified turret. The BT-7A often regarded as one of the more significant changes to the original platform featured a 76.2 mm howitzer making it an artillery tank.
Though the added weight removed the BT's unique property of being able to operate simply on road wheels alone. The BT-7A also had to be fitted with a turret borrowed from the T-28 Light Tank design to fit the gun.
The last variant being the most critical change to the vehicle was the BT-7M,[N 4] which brought about numerous additions to the base model. It had a new twelve cylinder engine allowing it to be fitted with a new 76.2 mm main gun. As such, several other minor modifications had to be made to the hull to accommodate the changes.
The BT-7 was the last of a long line of BT or fast tanks produced before it through numerous Soviet developments in the 1930s. Most of the prototype testings for the BT-7 went on from 1933-1934 and by the next year, the first examples were already put into production to serve with the Red Army. The first combat experience of the BT-7 was in 1938 against Japanese troops during early border clashes where it proved quite successful. They were then redeployed to be used against Poland in 1939 and were one of the more plentiful tanks in Soviet stocks when Operation Barbarossa began.
Despite a thus far successful combat record, poor maintenance eventually caught up with the tanks causing hordes of the vehicles to break down and or be destroyed in action in swift movements of German troops. Even by the Battle of Kursk, BT-7s were still fielded by Red Army tankers and it proved to be one of the most successful designs of the Soviet Union. Its last operation was in 1945 when the Soviet Union struck back and invaded Japanese troops stationed in Manchuria. In total, around 2,700 examples were produced by war's end.
- ↑ BT meaning "fast tank" in Russian.
- ↑ Some models had the option to mount a DT machine gun in the rear of the turret
- ↑ This design later earned this model the nickname of "Mickey Mouse" by German troops encountering it in combat
- ↑ Also known as the BT-8.
- ↑ 1.0 1.1 Forty, George. WW1 and WW2 Tanks. Southwater Books (Anness Publishing Ltd). 2012. ISBN 1 78019 190 1 Page 47
- ↑ http://www.wwiivehicles.com/ussr/tanks-medium/bt-7.asp
- ↑ http://www.militaryfactory.com/armor/detail.asp?armor_id=347
- ↑ Lüdeke, Alexander. Weapons of World War II. Parragon Books (2007), Page 117