• Military Menu                       

• Introduction
• Systems
• Facilities
• Agencies
• Industry
• Operations
• Countries
• Hot Documents
• News
• Reports
• Policy
• Budget
• Congress
• Links

• WMD
• Intelligence
• Homeland Security
• Space

BT-7 Light Wheeled-and-tracked Tank

The BT-7 tank was essentially a modernized design of the BT-5 tanks. The tank was developed building on the experience of use of the previous models of the BT-series tanks. Main emphasis was on improvement of the reliability, ease of manufacture as well as on enhancement of the combat characteristics. The BT-7 was the most well-developed of the BT series tanks. In accordance with the design documentation for the new tank, it was planned to install a more advanced and reliable M-17 engine, develop a welded hull with improved visibility for the driver, install increased-capacity fuel tanks and a 76-mm gun on the tank.

In general, the task involved the development of a “shock long-range wheeled-tracked tank”. A group of designers took part in the development of the tank: Firsov, Bondarenko, Morozov, Doroshenko, Kurasov, Veselovsky and Tarshinov.

The experience of battles in Spain (in which the BT-5 tanks participated) showed the need to have a better tank, and in the spring of 1938 the ABTU began to develop a BT successor - a high-speed wheeled-tracked tank with similar weapons, but better protected and more fireproof. The result was a prototype of the A-20, and then the A-30 (despite the fact that the military was against this car). However, these machines were rather not a continuation of the BT line, but the beginning of the T-34 line.

Carrying out further improvement of the BT series tanks, the designers of the T2K Design Bureau created in 1935 its follow-on version - the BT-7 tank. The tank was developed building on the experience of use of the previous models of the BT-series tanks. Main emphasis was on improvement of the reliability, ease of manufacture as well as on enhancement of the combat capabilities. The BT-7 was the most well-developed of the BT series tanks.

The tank was developed building on the experience of use of the previous models of the BT-series tanks. Main emphasis was on improvement of the reliability, ease of manufacture as well as on enhancement of the combat characteristics. The BT-7 was the most well-developed of the BT series tanks.

This tank was fitted with a M-17T carburettor aviation engine with better characteristics, and there were major charges to the transmission assemblies. Some of the tanks were equipped with anti-aircraft machine guns. In parallel with the release and modernization of BT tanks at KhPZ, they began to create a powerful tank diesel engine, which in the future was to replace the unreliable, capricious and fire-hazardous carburetor engine M-5 (M-17). As early as 1931-1932, the NAMI / NATI design bureau in Moscow, headed by Professor AK Dyachkov, developed a draft of a D-300 diesel engine (12-cylinder, V-shaped, with a capacity of 300 hp), specially designed for installation.

At the KhPZ, the 400th Division, headed by K. Cheplan, was engaged in designing tank diesel engines. The 400th Division collaborated with the department of engines VAMM and CIAM (Central Institute of Aviation Monitors). In 1933, the BD-2 diesel engine (12-cylinder, V-shaped, developing 400 hp at 1700 rpm, fuel consumption 180-190 g / hp / h) appeared. In November 1935, the diesel engine was installed on the BT-5 and tested. However, it was not until 1935 that the first prototype of this diesel engine was built at the Kirov Plant in Leningrad. It was installed on the BT-5 and tested. The results were disappointing, since the power of the diesel engine was clearly insufficient.

The BT-7 tanks had a redesigned hull, with a large internal volume, and thicker armor. Welding was widely used to connect armor plates. The tank was equipped with an M-17 engine of limited power and with a modified ignition system. The capacity of the fuel tanks has been increased. The BT-7 had a new main friction and gearbox, developed by A. Morozov. Side friction clutches used variable floating brakes designed by Professor V. Zaslavsky. In 1935, the plant was awarded the Order of Lenin for the merits of KhPZ in the field of tank building.

In 1935, mass production of the BT-7 tank began with the already tested turret from the BT-5 tank. At the same time, neither the military nor the designers abandoned the idea of creating a light tank with a 76-mm cannon. In addition, the design bureau of the GABTU received a task to develop a project BT-7, which would allow to install a turret from a T-26-4 tank on the vehicle. When the BT-7 tank began to be produced in 1935, it had a new engine and a number of other improvements. The first samples were produced with a cylindrical turret, which was soon replaced with a conical one; the tank ammunition depended on whether a radio station was installed on it.

For the creation of the BT-7 KhPZ in 1935 he was awarded the Order of Lenin. In March 1936, the diesel tank was shown to top party, government and military personnel. DB-2 required further refinement. Despite this, it was already adopted in 1937, called the B-2. At this time, the 400th Division was reorganized, ending with the appearance in January 1939 of the Kharkov Diesel-Building Plant (HDZ), also known as Plant No. 75. That HDZ and became the main manufacturer of B-2 diesel engines .

In 1937, the BT-7 serial tanks began to be produced with a conical turret, which allowed (without changing the composition of weapons) to increase the tank's ammunition by 44 rounds (188 rounds for tanks without a radio station, 145 rounds for a tank with a radio station). On all linear BT-7s in the stern niche of the turret, DT stern machine guns were installed. The BT-7 models of 1937 were equipped with special-type floodlights that were mounted on a cannon mask, which suggested the possibility of firing from a cannon and a paired machine gun at night. Subsequently, tanks equipped before 1937 were equipped with such headlights.

On the BT-7 of the first issues, as on the BT-5, cylindrical towers were installed. But already in 1937, cylindrical towers gave way to conical all-welded, characterized by greater effective thickness of armor. In 1938, tanks received new telescopic sights with a stabilized aiming line. In addition, they began to use loose-link caterpillars with reduced pitch on tanks, which showed themselves better during fast driving. The use of new tracks required to change the design of the drive wheels.

The gun pointing mechanism was improved in 1938 by introducing stabilization of the aiming line in the vertical plane. In 1936-1937 on the part of the tanks, a 76.2-mm QD gun was installed with an initial projectile speed of 381 m / s (BT-7A), of which 155 units were fired.

Compared with the BT-5 tanks, the new tank had an improved hull shape, thicker armor, a large supply of fuel and a range. The technical reliability of these machines especially increased after installation in 1939 on tanks of the latest modification of the BT-7M diesel engine B-2. Immediately increased speed and power reserve, since the diesel engine was primarily much more economical than a gasoline engine. Production of the BT-7M was stopped due to the transition to the production of T-34 tanks in the spring of 1940, and more than 8,000 BT tanks of various modifications were produced in the USSR.

The tank was used in local military conflicts of the 1930s and in the Great Patriotic War. New Bt-7 tanks were mainly armed with tank brigades of tank corps and separate tank brigades. BT-7 tanks were originally supposed to be used to develop breakthroughs into the depths of the enemy’s defenses. BT-7 received baptism of fire in battles at Lake Hassan in August 1938. Then the BT-7 participated in the battles at Khalkhin Gol, where out of 493 tanks 48 were lost forever. In general, the tanks received good reviews, however, the difficulty of controlling the vehicle was noted, which required excellent training for the driver. And - a weak bulletproof reservation along with a massive lack of radio stations, which made it difficult to control large groups of tanks in battle.

The BT-7 tank became the symbol of the armored forces of the Red Army, because, along with the identified shortcomings, it had simply excellent maneuverability, speed and “jumping ability”. Armor, rapid onslaught and firepower. BT-7 was used in the battles of World War II. It is believed that the tank is obsolete by June 1941, which led to massive losses. However, the use of BT-7 for inappropriate purposes led to massive losses. BT-7 was not intended for the breakthrough of a prepared defense or oncoming tank battle.

On June 23, 1941, the crew of Sergeant Naidin on the Bt-7 tank in one day destroyed 15 German tanks and 10 artillery pieces. The tank acted suddenly from ambushes. At the same time he was engaged in a battle with a superior opponent (one against a tank company). The last time the BT-7 tanks took part in the battles in August 1945 as part of the 1st Far Eastern and Trans-Baikal Fronts. And the final stage of the BT-7 service was the victory parade in Harbin.

Total production of the BT-7 was 4,965 vehicles. By another account, from 1935 to 1940, 5,328 BT-7 tanks of all modifications were produced (not counting the BT-7A). They were in service with armored and mechanized troops of the Red Army for almost the entire war. The work on improvement of the BT series tanks was carried out under the leadership of A.O. Firsov.