Russian Light Tank BT-2 (Tier II)

The BT tanks (Russian: Быстроходный танк (БТ), Bystrokhodny tank, lit. "fast tank" or "high-speed tank"^[1]) were a series of Soviet cavalry tanksproduced in large numbers between 1932 and 1941. They were lightly armoured, but reasonably well-armed for their time, and had the best mobility of all contemporary tanks of the world. The BT tanks were known by the nickname Betka from the acronym, or its diminutive Betushka.^[2]

The direct successor of the BT tanks would be the famous T-34 medium tank, introduced in 1940, which would replace all of the Soviet fast tanks, infantry tanks, and medium tanks in service.

Design

The BT tanks were "convertible tanks". This was a feature designed by J. Walter Christie to reduce wear of the unreliable tank tracks of the 1930s. In about thirty minutes the crew could remove the tracks and engage a chain drive to the rearmost road wheel on each side, allowing the tank to travel at very high speeds on roads. In wheeled mode the tank was steered by pivoting the front road wheels. However, Soviet tank forces soon found the convertible option of little practical use in a country with few paved roads, and it consumed space and added needless complexity and weight. The feature was dropped from later Soviet designs.

Christie, a race car mechanic^{[citation needed]} from New Jersey, had tried unsuccessfully to convince the U.S. Army Ordnance Bureau to adopt hisChristie tank design. In 1930, Soviet agents at Amtorg, ostensibly a Soviet trade organization, used their New York political contacts to persuade U.S. military and civilian officials to provide plans and specifications of the Christie tank to the Soviet Union. At least two of Christie's M1931 tanks (withoutturrets) were later purchased in the United States and sent to the Soviet Union under false documentation in which they were described as "agricultural tractors."^{[citation needed]} Both tanks were successfully delivered to the Kharkov Komintern Locomotive Plant (KhPZ). The original Christie tanks were designated fast tanks by the Soviets, abbreviated BT (later referred to as BT-1). Based both on them and on previously obtained plans, three unarmed BT-2 prototypes were completed in October 1931 and mass production began in 1932. Most BT-2s were equipped with a 37 mm gun and a machine gun, but shortages of 37 mm guns led to some early examples being fitted with three machine guns.

The sloping front hull (glacis plate) armor design of the Christie M1931 prototype was retained in later Soviet tank hull designs, later adopted for side armor as well.

The BT-5 and later models were equipped with a 45 mm gun.

Russian Light Tank MS-1 (Tier I)

The T-18 light tank (also called MS-1, Russian: Maliy Soprovozhdeniya-Perviy, "First Small [Vehicle for] Support") was the first Soviet-designed tank. Produced from 1928–31, it was based on the Renault FT, with the addition of a vertically sprung suspension.

The T-18 and its derivatives were essentially unsuccessful designs, but they gave Soviet industry its first experiences in designing armoured vehicles, and in the meantime a number of foreign tank designs were available for production.

Type	Light tank
Place of origin	Soviet Union
Production history
Produced	1928-1931
Specifications
Weight	5.9 tonnes
Length	4.38 m (14 ft 4 in)
Width	1.76 m (5 ft 9 in)
Height	2.10 m (6 ft 11 in)
Crew	2
Armor	6-16 mm
Main armament	37mm Model 28
Secondary armament	1 Fyodorov machine gun
Engine	T-18 35 hp (26 kW)
Power/weight	5.9 hp/tonne
Suspension	vertically sprung
Operational range	50 km (31 mi)
Speed	17 km/h (10 mph)

Development

A "Tank Bureau" was formed in May 1924 for the development of Soviet tanks. A specification was issued for a 3-tonne two-man light tank capable of 7.5 mph (12.1 km/h). It would be protected by 16 mm of armour and equipped with a 37 mm (1.5 in) gun. By 1925 the allowable weight had increased to 5 tonnes.

The tank was designed by Professor V. Zaslavsky at a new Tank Bureau set up under the Central Directorate of Military Industries. The 35-horsepower truck engine (a copy of the Italian FIAT 15 ter) was supplied by the Moscow AMO Factory, and the gun was a modified copy of the French 37 mm Puteaux SA 18 cannon. The sprung suspension which would allow a tank to travel faster over rough ground was the biggest improvement over the Renault. A prototype called the T-16 was tested in June 1927.

The T-16 was deemed a failure, as it had problems with its transmission failing too often and its inability to cross trenches more than 1.5 m wide.^[1] The T-16's maneuverability was only marginally better than that of the Renault. Meanwhile the КБ ОАТ drew up plans for an improved version of the T-16 which was accepted for production in July as the T-18, with the tank additionally noted as an MS-1 ("Support vehicle, small, type 1").

The T-18's chassis and suspension was improved from the T-16 by the addition of an extra support roller and an independent vertical spring suspension. The 300 mm track of the T-16 was transferred over to the T-18, with some improvements. The engine, a vertical, four-cylinder MS engine, was designed and improved upon by Alexander Mikulin. The engine was capable of a maximum of 35 horsepower. The MS engine was combined with the PSC transmission in one unit rather than being in two separate housings. The PSC transmission gave the tank four forward speeds and one reverse speed. The engine-transmission compartment in the back let air in via holes drilled in the rear plate. This improved protection, but also led to the engine overheating. Electrical equipment included a 6-volt battery, magneto and dynamo, which fed the lamp, horn, rear light, light distribution panel and two portable lamps.

Armor for the T-18 consisted of six 8 mm curved plates for the turret (covered with a mushroom-style cap of 3 mm thickness), 16 mm plates for the hull, and the bottom plates were 3 mm thick. An emergency exit was installed in the underside. A small circular or rectangle hatch was placed in the turret for ventilation.

The T-18s armament stayed the same as that found on the FR-17 and T-16, the French 37 mm Model 28, mounted in a Hotchkiss-system mantle. This gave the gun a range movement of 35 degrees horizontal, and +30 to -8 degrees vertical. This was coupled by a simple system of diopter sights. The 37 mm Model 28 was nearly obsolete by this time. That, coupled with a lack of optical sights, gave the T-17 little chance of taking out larger, better armoured opponents. However, with its 10–12 rounds per minute rate of fire and with the use of shrapnel projectiles it proved capable of combating infantry and soft vehicles. A double-barrelled 6.5 mm Fyodorov machine gun was mounted in a ball mount. Total ammunition carried was 104 37 mm shells and 2,016 6.5 mm cartridges. In later models the Fydorov was replaced by the 7.62 mm DT machine-gun.

Demonstration of the T-18 took place in mid-May 1927, but in combat tests its ability to move over rough terrain and fight effectively were not immediately apparent. A special commission comprising representatives of the Supreme Economic Council Mobupravleniya, OAT factory "Bolshevik", Artupravleniya, and the headquarters of the Red Army were on hand for the tests. During trials to overcome obstacles the T-18 behaved no better than the FT-17, with its biggest problem being trenches or ditches wider than 2 m and deeper than approximately 1.2 m. The machines often became stuck trying to cross these obstacles and needed to be pulled out by a tractor or another tank. However, the T-18 proved to be more "nimble" than the FT-17 or T-26 and had a maximum road speed of 18 km/h. In addition, in comparison with foreign analogues, the T-18 had better armour and a little more room for ammunition reserves.

Despite its problems, the T-18 was an improvement over the FT-17 and T-16, so 108 tanks were ordered into production starting in February 1928. Production took place at the Leningrad Obukhov Factory (later renamed Bolshevik Factory). The first batch of 30 tanks were found to have serious technical problems. After several interruptions, and the inclusion of the Motovilikhinsky Machine-Building Plant (Former Perm Artillery) to increase production the two plants were able to deliver 96 of the promised 133 tanks in 1929.

Another round of trials was completed in Moscow to address the T-18s inability to cross 2-m-wide ditches. To solve this problem, a "tail" was added to the front. The tank could now overcome widths of 1.8 m, but it hindered the visibility of the driver and was thus abandoned. An improved T-18 with a better 40-horsepower engine, improved suspension and added turret bustle proceeded from 1929 to 1931, with a total of 960 tanks built. Plans were made to replace the main gun with new 37 mm B-3s, but were never implemented.

A number of experimental designs based on the T-16 and T-18 were tested at the Bolshevik Factory, leading to the T-19 tank with a 90 hp engine in 1931, and the T-20 with a 60 hp engine. The new T2K Tank Design Bureau (later renamed Morozov Design Bureau) at the Kharkov Locomotive Factory used the T-18 as the basis for the new T-24 tank.

Operational history

Service in the forces of the first Soviet tanks did not leave behind a large number of clear combat examples. An experimental company equipped with T-18s took part in defending the Far Eastern Railway against Manchurian forces in 1929. They were removed from service in 1932 and given over to training. Following the German invasion of the Soviet Union a number of MS-1s were given 45 mm (1.8 in) guns and entered service as the T-18M.