BT-7 Model 1937
Further improvements of the BT-5 Model 1934 tank led to the BT-7 Model 1935. The new BT-7 used the same turret as the BT-5 but had a redesigned front hull. The muffler at the rear were now entirely closed. A new shortpitched track was introduced, and a new M-17T engine was fitted, providing 450hp. Maximum armor was increased from 13mm to 22mm. The hew BT-7 hull were largely electro-welded instead of the former use of rivets. The redesigned hull resulted in a greater fuel capacity. The BT-7 and BT-7TU Model 1935 remained in production until 1937 when the BT-7 Model 1937 was introduced. It used a new sloped turret, otherwise it was nearly identical to the BT-7 of Model 1935. The BT-7TU Model 1937 command tank most often used a whip antennae instead of the old horseshoe-antenna seen on BT-5TU Model 1934 and BT-7 Model 1935. In 1938, the continious strive to improve the model led to a modified version known as BT-7M. This featured a new V-2 diesel engine, and as on late production vehicles of the BT-7 Model 1937, the BT-7M had a ball-mounted machinegun in the turret rear, but later redesigned hatches on the roof permitted a P-40 AAMG to be fitted.
The BT-7A was the artillery version of the vehicle armed with a 76.2mm Model 1927/32 L/16 howitzer in an enlarged turret. It was produced in quantity, but no numbers have been found.
The OP-7 was a flamethrower variant of the BT-7 Model 1937 which mounted the fuel cell for the flamethrower externally in an armored pannier on the right hull side. It was never produced in quantity.
Production of the BT-8 began in 1939, and 706 were built during 1940. Only a small number were built in 1941 before production was terminated. A prototype of a BT-8A was planned, with a 76.2mm in a more roomier turrett than that fitted on the BT-7A, but it never reached longer than to a scale model. The BT tank was known as "Betka" or "Betushka", and a total of 7.000 BT tanks were manufactured.
BT-7 Model 1935 on display at the Central Army Museum
Photo provided by: George Mellinger.