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WWII Soviet Fast Tanks

BT-2

Soviet Union Soviet Union (1931)
Fast Tank – 620 built

In 1928, the Soviet Union dispatched a military commission with the aim of finding an adequate and advanced foreign tank design. While visiting the USA, they came across the automotive designer J. W. Christie, who presented them with his own tank design. The Soviets were impressed, leading to the acquisition of two vehicles, followed up by a license for production of that design in the Soviet Union. The vehicle which was built in the Soviet Union was known as the BT-2 and, while not perfect, it would be built in relatively large numbers and serve as the basis for future more successful developments.

The BT-2 fast tank. Source: Pinterest

Why a fast tank?

The BT-series tanks have often been associated with the theory of Deep Operations. While BT tanks eventually found their place and role within the cutting-edge doctrine, the reasons why BT tanks were adopted into service with the RKKA (The Red Army of Workers and Peasants, Russian: Raboche Krestyanskaya Krasnaya Armiya) are much more complicated.

In the mid-twenties, the Soviet leadership found themselves in isolation aggravated by deteriorating international relations. At the time, Great Britain was considered the primary enemy of the young Socialist Republic.

Troubled with rising tensions with the international community, the Soviet leadership decided to inspect the RKKA and determine its readiness for a future war. On 26 December 1926, the General Staff of the Red Army prepared the report “The Defence of the USSR”. The results were disastrous. Presenting the report to the Soviet leaders, the Chief of Staff of the RKKA, Mikhail Tukhachevsky, admitted the unpleasant fact ‘Neither the Red Army nor the country are ready for war.

The consequences were twofold: firstly, the situation forced the Soviet leadership to pay attention to defense issues and urgently start a massive reorganization of the Red Army; secondly, the Soviets and Stalin himself, who, by that time, had increased his influence significantly, got an opportunity to use the ‘war scare’ as a part of internal policy, justifying the most extreme measures.

In December 1927, Tukhachevsky sent a memorandum to Voroshilov entitled “On the radical rearmament of the RKKA”. The document stressed the fundamental technical rearmament of the army as a key aspect of a successful defense policy. Later, that notion became more precisely formulated ‘to keep up with our enemies in the strength of the mobilized army and surpass them in materiel’.

Accordingly, the cornerstone of the technical rearmament of the Ground Forces was the plan to increase the level of mechanization dramatically. Eventually, technical rearmament and mechanization of the Red Army even got its own name and became known as tankization, or ‘tankizatsiya’ in Russian.

The first three-year plan presented in January 1927 anticipated producing only 150 tanks by 1930. The next plan, part of the first five-year plan, anticipated the growth of the tank fleet fifteen times compared to 1928/29. This was quite an ambitious rate considering the state of the economy and industrial development of the USSR at the time.

The plans for future production were based mostly on projections that clearly overestimated the industrial capacity and technological potential of the country. In reality, the Soviet tank program bumped into numerous difficulties with both development and production. The RKKA had only adopted into service its first indigenously developed tank, the T-18 (MS-1), in July 1927, and started its low-rate serial production in mid-1928, with only 30 tanks being built that year.

In 1928-29, production was moving slowly, experiencing constant delays of delivery and poor quality of production. For example, on 24 September 1929, the Ordnance-Arsenal Trust reported that the Bolshevik factory (No 174) would delay production for 1-2 months and the MMZ (Motovilikhinskii zavod No 172) for 8-10 months.

Additionally, in 1929, a new system of tank-tractor-auto-armored weapons of the RKKA was adopted. The document made the T-18 tank obsolete and envisaged the adoption of even more sophisticated armored vehicles in increasing numbers. Knowing these circumstances, the command of the RKKA and Tukhachevsky himself had every reason to question the ability of the Soviet industry to cope with the plan on its own and within an acceptable time frame. In November 1929, the Department of Mechanization and Motorization (Управление по механизации и моторизации, UMM) of the RKKA had to admit that ‘there is no certainty that the program will be completed’.

The remedy to this situation was quite obvious — to seek technological help abroad. The decision was made, and on 30 December 1929, the commission led by the head of the Directorate of Mechanization and Motorization of the RKKA (UMM RKKA), Innokentii Khalepskii, went abroad. The plan envisaged visiting the US, Great Britain, Czechoslovakia, France, and Germany in order to purchase technologies and armaments.

It was a juxtaposition that the Soviets were determined to find help in hostile bourgeois countries (as they were presented by official propaganda) including Great Britain, the most likely enemy state in case of war. There was another significant point regarding the connection between the Deep Battle/Deep Operations doctrine and BT tanks. Despite the fact that some elements of the future doctrine were developed by Tukhachevsky back in 1926, he was not an active supporter of mechanization until 1928-29 and saw cavalry as a main maneuver element of the army. In May 1927, presenting the new plan of military development, Tukhachevski did not even mention armored forces or tanks at all.

Although Soviet advocates of mechanization were well aware of the technological and tactical developments in other countries, including British experiments with the Experimental Mechanized Force and convertible tanks, there were no fast tanks in the system of tank-tractor-auto-armored weapons of RKKA of 1929.

The system, however, included convertible tankettes with a maximum speed of 60 km/h on wheels and 40 km/h on tracks, but their tactical role was confined to reconnaissance, surprise assault, or anti-tank defense in a variant armed with a 37 mm gun. Obviously, not even close to the role of fast tank, which was a crucial part of the independently acting mechanized formations and the Deep Battle doctrine in general.

Eventually, having appreciated the advantages and high potential of the new combat vehicles acquired from the US, the Soviet military command began to see Christie tanks as a unified platform capable of performing different tasks. ‘This type could be used not only as a tank but as a troop, machine gun, artillery, and ammunition transporter, etc., also as an armored car for the motorization of the cavalry… it could be used as a platform for carrying AA-guns, machine guns, and searchlights. Field artillery could also be put on Christie’s chassis, which surely addresses the problem of the motorization of artillery… Chemical forces, signal, and technical troops could also use Christie’s vehicle’ said the note on the organization of armored forces abroad issued on 20 January 1930.

We can assume that combat vehicles with characteristics similar to Christie’s tanks were not considered in the early stages of working on the novel theory of Deep Operations. The adoption of the BT-2 tanks luckily coincided with the development of the theory in the early 1930s and the capabilities of the military equipment successfully corresponded with the needs of the innovative theory of Deep Battle.

American origin

During the Great War, Christie was involved in designing tracked self-propelled artillery vehicles. When the US Army obtained a number of French FT tanks, Christie noted that the tank, and especially its suspension, was prone to malfunctioning and breakdowns during long distance marches. The solution used at the time was to use trucks as transport vehicles to avoid unnecessary wear of tank engines and running gear. While quite effective, this way had also some drawbacks, such as the necessity to have a large fleet of trucks (also prone to breakdowns), hard limits on weight and dimensions, and a relatively low speed of movement.

John Walter Christie. Source: Wiki

During this time, Christie came up with a new concept for a convertible armored vehicle. He simply devised a plan of using a track suspension system that could, if needed, be easily modified and used as a normal wheeled vehicle by simply removing the tracks. His first tank prototype to use this kind of suspension was presented to the US Army in early 1921, named ‘M1919’. While the vehicle was trialed at the Aberdeen Proving Ground (APG), a number of problems were noted. For this reason, Christie spent some time modifying and improving his design, which he again presented to the Army in 1923.

Once again, this tank was rejected due to many flaws in the design. Once more, Christie completely redesigned his suspension system. This time, he incorporated four larger road wheels, with the idler in the front and the drive sprocket at the rear. The last road wheel was connected with a chain belt to the drive sprocket, and was used to provide drive power when the track links were removed. The front road wheels were used for steering. During 1928 (thus the name ‘M1928’), Christie himself made great efforts to advertise his vehicle, especially to the US Army, but also to customers abroad. He actually managed to gain attention from Poland and from Soviet Army representatives.

The Christie M1928 tank design. Source: Pinterest

At that time, the military and political relations between the US and the Soviet Union were almost non-existent, as the US did not even recognize the USSR as a state. Thus, any possible cooperation with Christie would be difficult to achieve.

At the time, the main base of operations for the Soviets in the US was the Amtorg Trading Corporation entrenched in New York. Amtorg was founded in 1924, with the official goal of facilitating trade operations between the Soviet Union and the United States and help with import-export operations as an intermediary. Additionally, the Soviets also used Amtorg as a cover for intelligence operations. Interestingly, Amtorg was an officially registered stock company embedded into the American market and legal system, meaning the Soviets could obtain valuable intelligence without any covert operations.

Amtorg could officially request information about any company registered in the USA on the grounds that they wanted to make a deal. Moreover, it was impossible to prevent them from doing this, since by submitting official requests, they did not go beyond the legal field, being an incorporated subject of economic activity. In this regard, federal officials called Amtorg a “bridgehead of Soviet espionage” and the oldest Soviet intelligence agency in the United States. Through Amtorg, the Soviets managed to acquire a number of technologies and, later, even weapons from the USA.

With the Amtorg Corporation, the Soviets had stationed a group of undercover military officers whose task was to try to obtain more modern military equipment under the guise of purchasing equipment for civilian purposes. While American authorities from the early twenties were strictly opposed to selling any kind of weapons or military equipment abroad, and especially to the Soviet Union, by the end of the decade, this attitude changed. To this end, at the end of 1929, Amtorg officials asked for permission to buy 50 Cunningham T1E2 light tanks (this tank never actually entered production beside the prototype), but nothing came from this, mostly as the Christie design looked more promising and was available.

The Soviets were initially interested in acquiring a number of Cunningham T1E2 tanks, but in the end nothing came from this. Source: Wiki

In 1930, a Soviet delegation led by I. Khalepskiy, who was in charge of the Red Army Mechanization and Motorization Directorate (UMM), and D.F. Budniak, the Defence Industry representative, visited a number of American weapons and arms manufacturers, including Christie’s own plant. The Soviets were highly impressed with the M1928 vehicle and, after they informed the People’s Commissar for Defence, Kliment Voroshilov, it was agreed to acquire two vehicles for testing and even to obtain a production licence.

In June 1930, after long and difficult negotiations, Christie signed a contract with the US Army to deliver one tank for $55,000, along with $7,000 allocated for trials and fine-tuning of the engine. In the meantime, he was approached by Amtorg representatives with their own proposal and also managed to sign a separate contract with Poland to deliver one M1940 tank for $30,000 along with spare parts worth $3,000 and the production licence for another $90,000.

Knowing the Soviet fears and unwillingness to allow Poland to get any advantage over the USSR in tank production, Walter Christie skillfully used the situation in his favor. By the end of April 1930, an agreement was signed between Christie and Amtorg for purchasing two vehicles at a total price of $60,000 (over $933,000 in 2020 values), spare parts worth $4,000, followed by an agreement for a licence production and technical support for another $100,000.

The total sum was high enough to cover the costs resulting from breaking the previous contract with Poland. At the same time, to better familiarize with the construction and design of the M1928, about 60 Soviet engineers spent nearly a year at Christie’s company.

Although the contract had already been concluded, the actual delivery of these vehicles, on the other hand, was slowed to a halt by the US government. At that time, US government officials were unanimous that no weapons of any kind should be allowed to be exported to the Soviet Union. At the end of 1930, American authorities tried to find out what happened to the two M1928 vehicles. They were probably shocked and agitated to discover that these had already been dispatched to the Soviet Union under disguise as ‘tractors’.

The first Christie tanks in the Soviet Union

The Christie tanks finally reached the Soviet Union in early 1931. These two were of the M1940 model (based on the M1931 model), which had a more simplified frontal hull design. In order to ship them to the Soviet Union, they were disguised as tractors by removing the turrets, which had to be left behind.

Consequently, the Soviets had to design and build their own turrets. One of the two vehicles was moved to the Nakhabino Proving Ground for operational trials. The second vehicle was moved to the Ordnance-Arsenal Trust (GKB-OAT) in Moscow. The testing of the M1940s was completed by May 1931 and production orders were placed shortly thereafter. During the testing phase, the M1940 showed itself to be an unrefined design, but was nevertheless put into production. One of the reasons for this somewhat hurried attempt to start production was based on the false and incomplete information that the Poles were trying to adopt the same vehicle. While the Poles had indeed expressed interest in Christie’s tanks and experimented on improving the tank design, with what would be known as the 10TP, only a single prototype would be built by 1939. The other reasons lay within industrial and economical aspects and will be discussed further. Interestingly enough, the Soviets also obtained one M1932 tank model for further testing.

The Poles tried to develop their own tank the 10TP, based on the Christie chassis. Source: Wiki

The Name

When the M1940 was adopted for production, it received the BT-2 (Bystrokhodny tank – ‘fast tank’) designation. As claimed by S. J. Zaloga, the BT-1 designation was not used, as this name was already taken for a failed GKB-OAT (Head Design Bureau of Ordnance-Arsenal Trust) design project dating back to 1927. According to other sources, such as T. Bean and W. Fowler (Russian Tanks of World War Two), the BT-1 name was actually used for a direct copy of the Christie vehicle armed with machine gun armament. These sources claim that it was built in small numbers. J. F. Milsom (Russian BT series), on the other hand, notes that the BT-1 designation was used for the first prototype armed with twin machine guns.

Russian sources are more certain. The two prototypes purchased in America were designated as Original-1 and Original-2 (‘Оригинал-1’ and ’Оригинал-2’ in Russian). Mikhail Svirin claims that, in 1930, the head of the UMM RKKA, Innokentii Khalepskii, rejected the idea to name the new tank in accordance with the standard Soviet designation, using the letter “T” and sequential numbering, as tanks of this type were not presented in the System of tank-tractor-auto-armored weapons of RKKA. Thus, he proposed to designate that type of combat vehicles as “ST” or “BT”, meaning skorokhodnii tank and bystrokhodnii tank in Russian. Both names could be translated as fast moving tank or simply – fast tank.

From February 1933, all tanks armed with 37 mm gun or twin-machine gun mount were officially designated as BT-2 tanks. Interestingly, according to the same author, the BT was also unofficially known by the nicknames ‘Tri Tankista’ (three tankers) and ‘Betka’, which he translates as beetle, even though this particular word does not mean anything in Russian. It was also known by other nicknames as ‘Bete’ (phonetic pronunciation from the Russian БТ, БэТэ – BeTe) or ‘Beteshka’ (little BT) by its crews.

Production

In the late 20s and early 30s, the Soviet industry was in a state of disorder and deep systemic crysis. There were many factors affecting the military industry and the rearmament, from political and administrative to a lack of technologies and experienced personnel.

The leaders of the Soviet Union wanted ‘too much too fast’ following their policy of the war scare emerging in 1927. Making things harder, the first five year plan (1928-1932) and, accordingly, the industrialization had just begun and had not produced any significant results yet. Simply put, the Soviet industry was not ready to meet the demands of the political and military leadership of the USSR within the acceptable time frame.

The proposed schedule was pretty tight even by contemporary standards: by 20 September 1931, the UMM RKKA wanted six prototype BT tanks to be ready; by 1 January 1932, the Kharkov Locomotive Factory (KhPZ) was to finish 25 BT tanks and 25 sets of spare parts, with another 25 tanks to be ready for acceptance trials. The first 100 BT tanks were to be ready no later than 15 February 1932.

By 1 December 1932, the Red Army expected to receive 2,000 BT tanks. Totally, by the end of the reorganization, the RKKA planned to have 4,497 BT tanks. This was quite an ambitious plan for a country which had started producing the indigenously developed T-18 tanks only in 1927 and, according to the previous plan of 1927/28, wanted 1,600 MS-1 tanks, 210 maneuver tanks and 1,640 Liliput tankettes by 1933.

As it was mentioned previously, there were no ‘fast tanks’ in the System of tank-tractor-auto-armored weapons of RKKA, which emerged in August 1929. Thus, the concept was completely new not only to the military, but also to the industry.

In order to start large scale production as quickly as possible, the Kharkov (KhPZ) locomotive plant was chosen. This choice was not random, as the KhPZ already had enough expertise in tank and tractor production and possessed almost all the necessary equipment to build M1940 Christie-type tanks.

On the other hand, KhPZ was already involved in the development and production of the T-24 medium tank and T-12 (A-12) ‘maneuver tank’ (manevrennii tank in Russian). Notably, the T-24 project was costly and progressed at snail speed, which was unacceptable for the senior leadership of the RKKA. Probably the main reason why the foreign project was chosen was its high readiness for serial production. The leaders of the UMM believed that putting Christie’s tank into production would be much faster, simpler and would not allow the management of the KhPZ to use deficiencies in the design as an excuse in case the factory would derail the production schedule.

Entrance to Kharkov Locomotive Factory (KhPZ) in 1940. Source: https://pastvu.com/p/359134

Needless to say, the management of the KhPZ was unhappy with the strict plans and, in fact, was wary of producing the new combat vehicle. Moreover, the director of the plant, Bondarenko, tried to stigmatize the tank by naming it ‘wrecking’. According to Gustav Bokis, at the time deputy chief of the UMM, “It took much effort, pushing and direct orders, up to the Government level, to force the KhPZ to build BT tanks and to make necessary amendments to the design in the course of manufacturing.”

To some degree, the concerns of the factory’s leadership were understandable. KhPZ was never designed for the mass production of tanks on such a large scale. The factory needed to expand, thus it needed new production facilities, workshops, raw materials, machine tools, and equipment which required resources and more importantly – time. Some machinery crucial for the production was not even available in the USSR and had to be ordered abroad from Germany, Switzerland, and the USA.

The BT tank project at KhPZ was entrusted to the special design bureau led by military engineer of the 2nd rank Nikolai Mikhailovich Toskin, beginning its involvement in the BT’s development on 25 May 1931. On 20 September 1931, KhPZ received the No. 70900311 order. According to the order, by 20 September 1931, the factory had to build six prototypes. Of them, only three tanks were ready by the deadline. The prototypes were to participate in the military parade in Moscow in November 1931, but only two of them actually made it. The third tank caught fire originating from the engine compartment before even entering the Red Square. According to Zaloga, these prototypes lacked any kind of weapons and were built using mild-steel plates.

Nikolai Mikhailovich Toskin. Source: KhKBM, 2007

The production moved slowly despite all the efforts being made. In addition to the issues mentioned before, the Izhorsky factory bumped into a series of problems producing armor plates for the hulls and turrets. By the end of the year, it had produced only three sets of armored hulls and turrets from a planned 50. Another source gave different numbers – the initial series of 13 hulls and 66 turrets were to be built using mild steel. Following all the unfortunate events, on 6 December 1933, Toskin was recalled back to Moscow and another engineer, Afanasii Firsov, took over the project.

Afanasii Osipovich Firsov, a talented Russian/Soviet engineer-mechanic. He studied at the Railway school in Russia, then continued his education at the Highest Technical School in Mittweida, Germany, and then at the Polytechnic Institute in Zurich. In 1930, he took a job at a “Russian Diesel” plant in Leningrad, where he was accused of being a wrecker (Wrecking or vreditel’stvo in Russian, which was a separate crime in the criminal code of law in the Stalin era. Unlike sabotage or diversions, wrecking meant deliberate acts of undermining or hampering the normal functioning of the State and its institutions. In practice, the definition was pretty vague, anyone could be accused of being a wrecker for any reason) and was arrested, eventually being sentenced to 5 years in a prison camp. On 18 September 1931, the Soviets decided that they needed a specialist with his knowledge and expertise and transferred him to Kharkov, where Firsov was assigned to the BT tank project. He was arrested again and executed in 1937. Source: Wiki

On 23 May 1931, the BT-2 was adopted into service with the RKKA and serial production began in the same year. The production plans for 1932 were overly optimistic, with an estimated production number of 900 vehicles. This number would be reduced to 482 vehicles, as it became obvious that the previous number would be impossible to achieve with the existing production capabilities.

On 3 October 1932, the chief of the Directorate of Military and Naval Inspection, Nikolai Kuibyshev, reported to Vyacheslav Molotov, the Chairman of the Council of People’s Commissars of the Soviet Union, that on 1 September 1932, out of the 900 tanks envisioned with the initial plan and 482 according to the corrected plan, only 76 tanks were ready. Of these 76 tanks, 55 were manufactured in August. The reduced plan for September was also derailed with only 40 tanks out of 120 completed.

Kuibyshev believed it was a clear indication that the factory intentionally lowered the standards of quality control in order to commission as many tanks as possible so they could take part in the autumn maneuvers. He also stressed that the quality of the produced tanks was low. All the BTs went to the army units as training vehicles.

According to the available reports from the military maneuvers of the Belorussian Military District, on the first day of the maneuvers, half of the vehicles were out of order. After the fourth exercise (250-300 km long march), out of 28 tanks, only 7 remained operational. In 1932, some 35 BT-2 were given to the 5th Tank Battalion for testing, but 27 required extensive repairs at the end of the year. The overall attempts to increase the speed of production greatly affected the mechanical reliability of these vehicles and the quality of spare parts and components, such as tracks, engines, transmissions, gearboxes, and others.

By the end of 1933, some 620 were built with 3 being built in 1931, 393 in 1932, and the remaining 224 in 1933. D. Nešić (Naoružanje Drugog Svetskog Rata-SSSR) mentions that 610 were built, but this does not correspond with the numbers in archive documents.

A report on all tanks received from industrial plants for the period from 1931 to March 1, 1940. See row No. 7, BT-2 tanks. Source: RGVA, F. 31811, O. 2, D. 1083

Design

The Hull and Superstructure

The BT-2 tank had a standard hull configuration, with a front crew compartment and a rear positioned engine, separated by a firewall with doors. The M-5 Liberty engine, an oil tank, radiators, and a battery were mounted in the engine compartment.

The hull had a simple box shape design with the front part having a wedge shape. While the original Christie vehicle was built using welded armor, the BT-2 was actually assembled using armored plates which were connected with rivets for ease of construction.

A front view of the BT-2. It had a simple box-shaped hull design with a pyramidal-shaped front where the driver was located. Source: wiki.wargaming.net

Suspension and Running Gear

Probably the main distinctive feature of the design was the ability to move on wheels or on tracks, which, in fact, predetermined many technical solutions of the future BT-series tanks.

The BT-2 used the Christie suspension system which consisted of four large road wheels on each side, one front idler, and rear positioned drive sprocket. Each road wheel was suspended with helical springs. The springs on the steering wheels were positioned horizontally and were installed inside the combat compartment. The rest of the springs were positioned vertically inside pipes and installed between the outer armor plate of the hull and the unarmored inner wall. The suspension allowed a road wheel vertical travel of up to 287 mm.

Illustration of the BT-2’s Christie suspension system, which used large helical springs. Source: Shmelev Igor. The History of a Tank (1919-1996) An Illustrated Encyclopedia.

While this suspension offered much better drive performance than previous ones, it had a huge disadvantage. It required a lot of space inside the hull. For this reason, the hull interior was cramped. Another huge issue was the maintenance and replacing of damaged or worn-out parts of the suspension.

Maintenance was, in fact, the most exhausting and time-consuming part of the crew routine, as BT-2 tanks required all the bearings of the roadwheel arms to be lubricated every 10 hours, and all bearings had to be lubricated every 30 hours of travel.

The design of the road wheels was changed during the BT-2’s service life. Originally, the front wheel had 12 small holes in it, while the remaining wheels had 6 spokes each. All four road wheels had rubber rims. The diameter of these wheels was 815 mm, while the width was around 200 mm. In later years, some vehicles were equipped with solid road wheels taken directly from the improved BT-5 vehicles. These wheels were slightly larger – 830 mm.

A BT-2 with the original large road wheel design. The road wheels with 12 holes (front) and cast spoked wheels are clearly visible. Source: windhund.fandom.com
A number of vehicles were equipped with solid press-formed road wheels also used with BT-5 and BT-7. These road wheels were a bit larger, at 830 mm versus the original’s 815 mm. This particular vehicle was captured by the Finns at Portinhoikka at the end of August 1941. Source: Sa-Kuva

The BT-2 could be driven using only the wheels by removing the tracks. In this case, the drive was provided to the rearmost road wheel, while the first set of road wheels was used for steering (similar to ordinary cars). The driver would use a standard clutch and brake system when driving with tracks, and a steering wheel when driving with the wheels. Once the tracks were mounted again, the steering wheel was stored inside the vehicle. Moving on wheels, the BT-2 could achieve much greater speeds on good roads. Another benefit of using the road wheels was lower fuel consumption.

A disadvantage of this system was the time needed (some 30 minutes) to remove or put back the tracks. The procedure was pretty laborious and challenging even for 3-men crews, not to say for two men. The weight of each track was about 345 kg. The crew had to remove the tracks, disassemble them into four parts and fasten them to the track shelves with belts. The problem was so acute that, in May 1932, UMM RKKA ordered to ‘Mechanize the removal and putting back of the tracks, as the time of 30-45 minutes required for removal and 15-30 minutes for putting back the track is extremely long.’ After changing from tracks to wheels, the crew had to adjust all the springs to align the vehicle and get the road clearance even at 350 mm.

The wheel configuration could only effectively be used on good roads, which were rare and far apart in the USSR during this period. Driving with them off-road was generally a bad idea. However, the wheeled set-up was in no way meant to be used anywhere near the front lines. When approaching the enemy, the tanks would change to tracked configuration before proceeding. Once removed, the tracks were usually placed atop the track guards.

Sometimes the BT-2 crews would use shortened tracks. This technique was pretty common and, in this particular case, turned a tracked BT-2 into a half-track. Source: Francis Pulham private collection
A front view of the BT-2-IS variant without its tracks. The steering front wheels are evident here. The same mechanism was present on the regular BT-2s. Source: wiki.wargaming.net

The tracks used were of the Christie type, which were 255 mm wide with 46 links (23 of them flat and 23 with grousers). As this track was produced in the Soviet Union, its quality was poor and was frequently prone to malfunctioning.

The Engine

The BT-2 tanks were powered by a 400 hp (294 kW) Liberty L-12 engine and its reverse-engineered Soviet copies produced under the name M-5. In its essence, it was a 12-cylinder V-shaped liquid-cooled carburetor aviation engine. With a full weight of 11 tonnes (the precise tonnage differs between the sources), the BT-2 had a power-to-weight ratio of 33.2 hp per tonne. Normally, the engine worked at 1,650 rpm. The engine could be started with two 1.3 hp ‘Mach’ (Russian “МАЧ”) starters or one 2 hp Scintilla electrical starter. There was also the possibility to start the engine with a hand-crank.

The BT-2 tanks were powered by an M-5 engine, which was a direct Soviet copy of the American Liberty L-12. Source: Wiki

According to official specifications, the serial BT-2 could reach a maximum speed of 70-72 km/h on a dry paved road (some sources even mention an astonishing 110 km/h, which sounds like an exaggeration). The maximum and average speeds in different road conditions are given in the table below:

Road conditions/Speed km/h On Tracks On Wheels
Dry paved road Maximum 50 70
Average 25-35 35-40
Unpaved back road Maximum 50 70
Average n/a n/a

Source: RGVA F. 31811, O. 2, D. 1141

When using tracks, the speed was a reduced, but still a respectable 50-52 km/h. Depending on the drive type (tracks or wheels), the operational range with a full fuel load of 360 liters ranged from 120 to 200 km. Older sources, such as J. F. Milsom (Russian BT series), give a range of 300 km, although this is doubtful. The gearbox had four forward and one reserve gears. The crew had to come out to switch from wheels to tracks or back. About 30 minutes was required to fulfill this operation.

Operational range of the BT-2 tank. On tracks – 120-160 km, on wheels – up to 200. Source: RGVA 31811, F 2, O 1141

On top of the engine compartment, a hatch door with a large air filter was placed. Originally, the BT-2 tanks were not provided with a protective mesh fence that protected the air intakes, but in later years, some vehicles were equipped with it. In addition, the large external mufflers would also be replaced with simpler twin exhaust pipes.

Capricious carburetor engines were prone to overheating, malfunctions, and even caused fires. While the Liberty L-12 and its M-5 copy were somewhat problematic, the main reasons for accidents were inexperienced crews and technical services, poor manufacturing quality, and even fire safety violations. Some Russian sources mention numerous accidents caused by the crews smoking near the fire-prone engines or while refueling.

On the other hand, the Head of the UMM RKKA, Khalepsky, in his report to Voroshilov on 29 April 1934, mentioned “…all BT tanks have Liberty-type aircraft engines purchased in America and partially M-5 engines transferred from aviation to industry for installation on BT tanks… Practical experience has established that these engines can operate in tanks 400-450 hours before overhaul…”. The number is quite remarkable on its own. Besides the fact that some BT-2 tanks survived to 1944 in the harsh conditions of the Northwestern Front, indicates that the engine itself was reliable enough when handled carefully, even taking into account that the Northwestern Front was quite static until 1944 and BT tanks were constrained to guard duties.

The Armor Protection

The BT-2 tank was relatively lightly armored. Initially, the UMM RKKA wanted the BT tank to have not less than 20 mm frontal armor, 13 mm side armor, and 6 mm armor for the roof and bottom.

Early production models were made of mark D armor plates and had armor thickness ranging from 6 mm to a 13 mm maximum. The hull’s frontal armor was 13 mm thick, sides 10 to 13 mm, while the rear was 13 mm. The top hull was 10 mm and the bottom was protected with 6 mm armor. The turret was protected by 13 mm all-around armor, while the roof was protected by 6 mm of armor.

BT-2 tanks of the later production batches had 13 mm thick front, side, and rear armor. The roof armor thickness was slightly increased from 6 mm to 10 mm. The turret was protected by 13 mm armor all around. After the Izhorsky plant started manufacturing the new type of armor named PI (Russian “ПИ”) in September 1932, the maximum thickness of the hull and turret increased to 15 mm.

The small frontal driver plate was positioned mostly at a 90° angle, with the rest of the front having a pyramidal shape placed at a 31° angle. Notably, the BT-2 tanks had no vision slits protected with ‘Triplex’ glass nor pistol ports protected with armored shutters.

The fragment of the document indicates the number of vision slits protected with triplex glass (none) and pistol ports with armored shutters (none). Source: RGVA 31811, F 2, O 1141

The Turret

The two Christie’s tanks purchased in America had no turrets at all. As the Soviet leadership wanted a tank armed with a gun, it was necessary to design a new turret from scratch.

According to Zaloga, the Soviets appointed engineer Anatoliy Kolesnikov to design a turret. Kolesnikov indeed worked at the KhPZ Design Bureau under the leadership of Afanasy Firsov. However, Kolesnikov finished his education at the Leningrad Tank Academy and joined the Design Bureau at KhPZ in 1931. Given the tight schedule (three prototypes should have been ready by 15 September 1931), it seems doubtful that the leadership could have entrusted the design of the turret to the young designer and without any supervision. It was most likely a team effort and Kolesnikov was part of the design group.

Anatoly Vasilyevich Kolesnikov, Russian engineer, and tank designer. He took part in numerous projects including BT-2, BT-5, BT-7, T-24, A-20, A-32, T-32, T-34 and T-44. Source: Wiki

Due to the importance of faster project implementation, the Soviet engineers chose to design a simple cylindrical turret. The armor plates were held in place with rivets. The top of this turret consisted of a flat rear part, where a square-shaped hatch door was placed. Additionally, there was a small hatch for flag signaling to the left of the hatch. The frontal half of the turret top was angled downward.

The early turret designs did not have the two additional square-shaped protective covers over the gun mantlet, which were added later for better protection. During production, the turret was also provided with small vision slits. Some turrets had pistol ports closed with armored plugs.

On the left is the early turret used on the BT-2. After the army requested a machine gun, a ball mount was added to it. The last picture presents the twin machine gun configuration that was used to equip tanks that lacked the 37 mm gun. Source: Бронеколлекция №1 1996. Легкие танки БТ-2 и БТ-5
Close view of a German captured BT-2 turret without its weapon. Also, note the open turret hatch door. Source: www.worldwarphotos.info

The Armament

Initially, the BT-2 tanks were to be armed with a 37 mm PS-2 gun developed by Petr Syachentov and a coaxial machine gun. This gun was actually a Soviet attempt to improve the performance of the French Hotchkiss 37 mm gun. This plan was discarded once the Soviets decided to adopt a copy of the German Rheinmetall 37 mm anti-tank gun instead, as it was a more modern design.

The Soviet-built K-1, which was a direct copy of the German 37 mm anti-tank gun, in some numbers before deciding to adopt the larger 45 mm anti-tank guns. Source: www.imfdb.org
37 mm AT-gun mod. 1930 (Rheinmetall). Source: TsAMO F.81, O. 12040, D. 372, Alex Tarasov’s collection

Based on the German gun, the Soviets developed a tank version named the 37 mm B-3 tank gun (factory designation 5K – K stands for the Kalinin plant where this gun was developed). In the summer of 1931, it was decided to adopt a mount with the 37 mm B-3 tank gun and a coaxial 7.62 mm machine gun as standard armament for the BT-2 tanks.

There are different interpretations of the decision:

According to Russian sources, GAU RKKA (Main Artillery Directorate) failed to design the prototype of the mount and, therefore, canceled its serial production. As a result, in the first quarter of 1932, the Izorsky plant had to alter the blueprints of the turret to accommodate two separate mounts (one for the 37 mm gun and the second for the machine gun) and then change the whole first batch of 60 already produced turrets.

After that, the Mariupol factory and Izhorsky plant produced the second batch of tank turrets, now redesigned for separate mounts. Each factory produced 120 turrets, 240 in total.

It was planned to switch to a new mount with a 45 mm 20K gun and coaxial DT machine gun, starting with the 301st tank. However, extensive testing revealed that the small size of the serial turret simply did not allow to do that. Instead, the Soviet engineers designed a new bigger unified turret which was subsequently used on T-26 and BT-5 tanks and on some armored cars, like the BA-3 and BA-6.

According to Zaloga, the initial batch of 60 turrets was designed for the canceled PS-2 Syachentov’s gun. As the B-3 gun was bigger, it was quickly realized that the turret’s design did not allow it to accommodate both the new gun and a coaxial machine gun. The Red Army’s command did not agree with the idea to omit the machine gun, thus the Izhorsky factory had to find another solution. Eventually, the first 60 turrets were altered to accommodate two separate mounts – the B-3 in a gun mount and DT machine gun in a ball mount to the right of the gun. To add more confusion, there are also different opinions on the adoption of twin-machine gun mounts as the main armament for BT-2 tanks.

According to the version given by Russian authors M. Pavlov, I. Pavlov, and I. Zheltov, Factory No. 8 was able to deliver only 190 B-3 guns to the KhPZ factory (Kharkov Locomotive Factory). As there were not enough tank guns, in May 1932, the Soviet leadership decided to arm the remaining BT-2 tanks with two 7.62 mm DT machine guns in twin-machine gun mounts named DA-2. The DA-2 was tested and adopted into service in the fourth quarter of 1933. Curiously enough, the DA-2 mounts were installed by the army repair services.

In turn, S. Zaloga sticks to the version that the Kalinin factory No.8 (which was the main production center of this gun) received orders to stop the production of the B-3 guns in 1931 due to the decision to switch production to the new 45 mm gun. At that time, only 352 B-3 guns were actually built.

Eventually, the solution to modify the BT-2 turret to be able to house the new 45 mm gun failed. Despite much testing and modification of the turret by adding a rear bustle, this was not possible, mostly due to the turret’s small size. Another suggestion was to reuse any available PS-1 guns, which were initially used to arm the obsolete T-18 tanks. This proposal was also rejected due to the PS-1’s poor armor-piercing performance.

As there were only enough B-3 guns to equip slightly more than half of the BT-2s, the remaining vehicles had to be left without any main armament, at least until another solution could be found. Despite lacking its weapons, some of these BT-2 were still used on military parades. As a result of all the given circumstances, BT-2 tanks had four different sets of armament:

1. Only a 37 mm gun
2. A 37 mm gun and a 7.62 mm DT machine gun in a ball mount
3. Two 7.62 mm DT machine guns in a twin-mount plus another 7.62 mm machine gun in a ball mount
4. Two 7.62 mm DT machine guns in a twin-mount and the third machine gun removed

The latter variant appeared for two reasons. Firstly, at some point, it became apparent that the commander was not able to operate two machine gun mounts efficiently at once, and secondly, the third machine gun took too much space in the already cramped turret. Therefore, a certain part (the precise number is currently unknown) of the BT-2 tanks armed with twin machine gun mounts had the ball mount removed, with an armored shutter being placed instead.

Armament Quantity of tanks
37 mm gun 65
37 mm gun + 1 x MG in a ball mount 115
Twin MG + 1 x MG in a ball mount 440
Twin MG mount unknown

Source: Soljankin, A.G., Pavlov, M.V., Pavlov, I.V., Zheltov, I.T. Tom 1. Otechestvennye bronirovannye mashiny. 1905–1941 gg. [Domestic Armoured Vehicles, vol. 1, 1905–1941.] M.: OOO Izdatel’skij centr ‘Eksprint’, 2005, Page 77.

 

This is how the armored shutter possibly looked like. Surviving BT-2 tank turret, now exhibited at the “Breakthrough of the Siege of Leningrad” Museum-Reserve at Kirovsk near St. Petersburg. Source: http://www.photo.aroundspb.ru/events/bt2/
A rare sight, the bottom of the surviving BT-2 turret. Note the details of the turret ring and the turret turning mechanism. Source: http://www.photo.aroundspb.ru/events/bt2/

However, a document dated 29 June 1939 indicated two variants of standard armament for BT-2 tanks — a 37 mm gun and one DT machine gun or three machine guns.

A BT-2 with a twin machine gun mount and possibly an armored shutter. It is also possible that the machine gun is temporarily removed from the ball mount. Source: Pavlov, M.V., Pavlov, I.V., Zheltov, I.T. BT Tanks , M. Eksprint, 2001 – 184 p. War Museum series
A BT-2 armed with three machine guns, two in a twin mount and the third in the ball mount to the right. Source: Pavlov, M.V., Pavlov, I.V., Zheltov, I.T. BT Tanks , M. Eksprint, 2001 – 184 p. War Museum series

The standard armor-piercing round for the B-3 37 mm tank gun had a weight of 0.66 kg and a muzzle velocity of 820 m/s. It could, at a range of some 500 m, penetrate 28 mm armor (at a 30° angle). The BT-2 was also provided with 0.645 kg high-explosive rounds.

PS-2 gun B-3 tank gun 45 mm tank gun
Full designation 37 mm gun PS-2 mod. 1930

(Russian – 37-мм пушка ПС-2 образца 1930 года)

37 mm gun B-3 mod. 1930

(Russian – 37-мм танковая пушка образца 1930 года Б-3)

45 mm tank gun mod. 1932/38

(Russian – 45-мм танковая пушка образца 1932/38 годов)

Origin Petr Syachentov Rheinmetall Factory No 8
Factory designation n/a * 5K 20K
Caliber, mm 37 37 45
Barrel length Unknown L45 L46
Rate of fire, rpm Unknown 10-15 12
Initial velocity, m/s Unknown 820 AP (Shirokorad)
825 HE (Shirokorad)
760 AP (RGVA)

335 HE (RGVA)

Weight, kg Unknown 150 313
Armor-piercing round B-160 BR-240
Weight, kg Unknown 0,66 1,425
Armor penetration at

300 m at 0 degrees

500 m at 0 degrees

500 m at 30 degrees

Unknown  

30 mm (Shirokorad)

35 mm
(Zaloga)

28 mm
(Zaloga)

 

 

 

38 mm

31 mm

HE round O-160 O-240
Weight, kg 0,645 2,15 (2,135 – RGVA)

* Was not approved for serial production.

Sources: S. J. Zaloga (2016) BT Fast Tank; RGVA F. 34014, O.2, D. 858; http://battlefield.ru/b3-1930.html ; А.Широкорад “Энциклопедия отечественной артиллерии”, 2000;

 

37 mm tank gun model 1930. Source: TsAMO, Alex Tarasov’s collection

The ammunition load for the main gun was 92 rounds stored in ammunition bins located in the hull. The elevation of the gun ranged from -5° to +21° (some sources mention -4° to +40°, but this seems unlikely).

The elevation and depression of the B-3 gun in the BT-2 turret. Source: RGVA 31811, F 2, O 1141

The secondary armament consisted of a 7.62 mm machine gun with 2,709 rounds of ammunition. BT-2 tanks armed with twin-machine guns had 5,166 ammo rounds. The machine gun ammo was stored in drums, with 63 rounds in a drum. BT-2 gun-armed tanks had 43 drums onboard and machine gun BT-2 tanks had 82 drums.

DA-2 twin machine gun mount with a mantlet sitting on its side. Source: M. Pavlov, I. Pavlov, M. Zheltov. BT Tanks. Source: (Павлов М. В., Желтов И. Г., Павлов И. В. Танки БТ. — М.: ООО «Издательский центр «Экспринт», 2001. — 184 с )

 

A close view of the BT-2’s 37 mm B-3 gun. This particular vehicle is lacking the ball-mounted machine gun. Source: Wiki
Unarmed BT-2 tanks during a military parade held in Leningrad in 1935. S. J. Zaloga (2016) BT Fast Tank.
A BT-2 armed with the DA-2 twin machine gun mount. The machine guns are missing on this vehicle, probably taken off by its crew before it was abandoned. Source: https://www.worldwarphotos.info/gallery/ussr/tanks-2/bt-2-bt-5-bt-7-tank/

The Crew

The original Christie tank design included only two crew members, with one placed in the hull and the second in the turret. In Soviet service, the BT-2 employed both one and two-man turret configurations. As previously noted, due to shortages of proper guns, some vehicles had to be rearmed with twin-machine gun mounts. These vehicles had only two crew members, the driver and the overburdened commander, who had to also act as a gunner and loader in addition to his primary role.

The standard gun-armed vehicles had three crew members. The driver, the commander who was also the gunner, and the loader, who was also responsible for operating the turret machine gun. In this case, the third crew member had to be added as the commander would simply be too overburdened otherwise.

The driver’s position was in the front hull of the vehicle. To access his position, he had two rectangular hatches. The upper hatch had a small vision slit in it. The loader and commander (or only the commander in the machine gun variant) were placed in the turret. The commander was positioned on the left side of the turret, while the loader was behind him, to the right. On the turret top’s rear, they only had one small hatch.

As the BT-2 was not provided with radio equipment, the commander had, for communication between different vehicles, to use either a signal flag or a pistol flare. For internal communication, the crew members used light signals.

A front view of this abandoned vehicle clearly shows the driver’s hatch doors. Source: https://www.worldwarphotos.info/gallery/ussr/tanks-2/bt-2-bt-5-bt-7-tank/
A schematic drawing of the BT-2 driver’s position. 1 — control panel, 2 – control levers for side clutches, 3 – steering wheel (in the folded position), 4 – pedal of the main clutch, 5 – brake pedal, 6 – accelerator pedal, 7 – coulisse mechanism lever (gate change gear lever?), 8 – frontal wheel springs, 9 – brackets for installation driver’s seat. Source: https://tech.wikireading.ru/7126

In combat

The BT-2 is often assumed to have been an unreliable vehicle during its use by the Soviet Army, but this is not entirely correct. The primary factors which caused frequent malfunctions and mechanical breakdowns were poor manufacturing quality, inexperienced personnel, and insufficient technical service. Thus, the problem could be considered typical for any Soviet material at the time. While some attempts were made to improve its performance, during the following years in service, it was replaced by the newer and improved BT-5 and BT-7 vehicles.

One of the first combat actions of the BT-2 was during the Soviet invasion of Poland, which started on 16 September 1939. As stated by Zaloga, of 1,764 BT tanks deployed in the campaign, 1,617 were newer BT-7 tanks and the remaining 147 were obsolete BT-2 and BT-5 tanks.

As Poland’s main defense focus was facing the Germans, there were only minor engagements involving Soviet armor. The losses were incurred mostly due to mechanical breakdowns.

A BT-2 during brief Soviet Invasion of Poland in 1939 Source: Francis Pulham private collection

Some were also used during the wars between the Soviet Union and Finland in 1940 and 1941. A large number of BT series tanks were used by the Soviets near Lake Ladoga. Due to nonexistent roads and poor terrain conditions, the BTs (and all other armored vehicles, for that matter) had limited mobility. The BT vehicles were more affected as, due to poor road conditions, they could not use their great speed and maneuverability as an advantage.

Another problem was a lack of spare parts which forced the Soviets to use them as static defense bunkers. Finnish soldiers managed to capture a number of BT-2s. These were not employed by their new Finnish owners. In 1943, there were some 15 BT-2s available in Finnish stocks. From 1944 onwards, some turrets were used as static defense emplacements. A few BT-2 turrets were even modified to be armed with the Finish 37 Psv.K/36 anti-tank gun.

An abandoned BT-2 vehicle during fighting in Finland in late August 1941. While difficult to see, this vehicle, for an unknown reason, had its turret machine gun ball mount removed and replaced with an armor plate. Source: SA-kuva
The surviving Finish modified BT-2 turret equipped with the 37 mm anti-tank gun. Source: https://www.finna.fi/Record/museovirasto.FF98EBF1647470782FCBD4C324A82A31

According to Zaloga, by the time of the German attack on the Soviet Union in June 1941, there were some 323 BT-2s in service within the Mechanized Corps. Russian archive sources suggest other numbers – 515 BT-2 tanks in May 1940, distributed to various units

The fragment of the document says ‘To use BT-2 tanks in the amount of 515 pieces as training vehicles until complete wear’. Source: Sistema vooruzhenij 1940 – Postanovlenija Glavnogo voennogo soveta RKKA o sistemah vooruzhenija RKKA [The system of armaments 1940 – Resolutions of the Main Military Council of the Red Army on systems of armaments of the Red Army]. RGVA, F. 4, O. 14, D. 2631, LL. 138–45. The document is dated 27 May 1940
During 1940 and 1941, Soviet tank formations were used mainly in infantry supporting roles. During the German invasion of the East, the BT-2, like other Soviet armored vehicles, were pressed into combat, where they were outmatched by their more tactically and technically superior German counterparts. While having good speed, the BT-2 tanks were plagued with mechanical unreliability, caused by general wear, poor mechanical maintenance, and lack of spare parts. By the end of 1941, the surviving BT-2 vehicles were mostly removed from the front line. However, some of the BT-2 tanks were actively used until mid-1942 and probably even until 1943.

It is worth noting that obsolete but still operational tanks, such as the BT vehicles, were often allocated to quieter sectors to perform guard or logistical duties or to the training units in the rear. Thus some of them survived even until 1943-44. Some turrets were used as static defense bunker emplacements

This document is an example of BT-2 tanks in service with the Red Army during the Great Patriotic War. On 20th May 1942, the 71st Separate Tank Brigade still had eight BT-2s, two T-26 tanks, and one T-38 light tank. According to the report, all tanks were in serviceable condition and ready for action. Source: TsAMO, F. 229, O. 0000157, D. 0014, P 718
A group of five BT-2 tanks that were captured by the Germans during June or July 1941 at an unknown location. These particular BT-2 tanks are believed to be in process of decommissioning out of service and were to be either scrapped or converted as armored firing points. Source: https://imgur.com/a/H9BE8Ef Francis Pulham Private collection Source: Francis Pulham Private collection

The modifications of the BT-2

The Soviets tested a number of modifications based on the BT-2 chassis. These included an artillery support vehicle, a flamethrowing version, an engineer support variant, an amphibious tank, and various minor modifications.

The BT-3, BT-4, and BT-6 projects

From December 1931 to September 1932, the KhPZ Design Bureau led by Firsov developed the BT-3 tank. This was simply a serial BT-2 with all the measurements of the threads recalculated from inches to centimeters. In the RKKA, this modification retained its old designation, BT-2.

The BT-4 was developed in July 1932 by the same design team at KhPZ. The main difference of the project from the BT-2 and BT-3 tanks was the use of a welded hull instead of a riveted one. The BT-4 also got side towing hooks and a mechanism that allowed the driver to open and close engine louvers from his seat. Additionally, the engineers changed the design of the hull and running gear, allowing easy access to the side springs. In the autumn of 1932, three prototypes were built, but as opposed to the planned welded hull, they had a combined riveted-welded construction.

The BT-6 was another experimental model developed in 1932. It was mainly based on the BT-4 prototypes, but its turret and armament were taken from the BT-5. Other improvements included restoring the BT-2-like towing hooks and a different design of the driver’s hatch, which now had a lock and ensured protection from splinters. The BT-6 also had redesigned rear armor and the protection of the reduction gear. Work on the BT-6 was discontinued in late 1932.

All these experimental works were discontinued in 1932-33 due to the introduction of the improved version of the fast tank – the BT-5.

BT-6 tank without its main armament. Source: https://henk.fox3000.com/BT.htm

Artillery support tank project (D-38)

Following the introduction of the BT-2, several different projects were initiated with the aim of increasing its firepower. In 1931-33, a few design bureaus proposed designs with new armament and turret designs for the BT-2. These included the tank department of the KhPZ, NATI, the design bureau of the UMM RKKA led by Dyrenkov, the design bureau of the “Krasny Proletary” factory, and the design bureau of the “Krasny Putilovets” factory. Numerous variants of armament, including 37 mm, 45 mm, 76.2 mm Syachentov’s gun, and 76.2 mm Garford ‘anti-storm’ gun were suggested.

In 1931, Dyrenkov’s bureau proposed a variant armed with a 37 mm gun in a rotating turret and a 76.2 mm gun in the hull. The same idea was being utilized in the design of the French B1 tank. This design was rejected due to the insufficient space in the fighting compartment and the poor design of the transmission. As this was just a design proposal, no mock-ups or prototypes of this vehicle were built.

After the first design was rejected, Dyrenkov developed another one, which was more successful and subsequently was named D-38. In January 1932, the first prototype was built. This D-38 project had two variants of the turret. The first was welded, made of flat armor plates, whilst the second variant was cupola-shaped and made of pressed steel. Initially, Dyrenkov wanted to install two guns, a 76.2 mm ‘anti-storm’ Garford gun and a 37 mm tank gun, but then dropped that idea and used a PS-3 76.2 mm gun. Ultimately, the project was rejected and only one prototype was built.

A front view of the D-38 prototype vehicle with the welded turret. Source: unknown

Flamethrowing BT-2 (KhBT-2)

At least one BT-2 was tested with a flamethrowing system. The vehicle, known as KhBT-2 (Kh-Khimicheskiy means chemical), but also as KhBT-II and BKhM-2, had its main gun replaced with a KS-23 flamethrower. Possibly (but it is not clear in the sources) only one was built. At least one vehicle was also tested with smoke emitting equipment, but no production order was given. This flamethrowing idea was also trialed on the BT-5 and BT-7.

The BT-DT smoke creating tank prototype. Source: J. F. Milsom, Russian BT series, Profile Publication.

Amphibious tank project (PT-1)

During 1931-33, Soviet Army officials were interested in the idea of adapting the BT-2 tank as an amphibious vehicle and the industry responded. The first prototype, the PT-1 amphibious tank, was developed in 1931-32 at the technical department of the EKU OGPU (The Economic Directorate of the OGPU) and built at the ‘Krasny Proletary’ (Red Proletarian) factory. In Autumn 1932, the PT-1 was demonstrated to the Soviet leadership and Stalin himself, who approved the design, albeit admitted that it was quite unusual.

The second prototype, PT-1A (actually there were two of them, but the second prototype was never finished) was built and tested in 1934 at Kirov’s factory (No 185) in Leningrad. The PT tanks proved themselves surprisingly good. According to Russian sources, there existed plans to continue the development of the PT-1 in two directions — amphibious and non-amphibious tanks. Moreover, in 1933, there existed a plan to alter the system of armaments and replace older BT tanks with PT-1 tanks.

The project ended in 1935 when the USSR Council for Labor and Defence (STO – Sovet Truda i Oborony) decided to leave BT tanks in serial production.

The PT-1 amphibious tank prototype. Note the machine gun ball mounts in the turret and frontal glacis plate – the distinctive feature of the first prototype. The second prototype, PT-1A, had only one machine gun at the back of the turret. Source: Domestic Armoured Vehicles, vol. 1, 1905–1941
Front view of the PT-1 amphibious tank. Source: Domestic Armoured Vehicles, vol. 1, 1905–1941

Engineer version (SBT)

Probably the only successful adaptation of the BT-2 was the SBT (Saperniy bystrokhodnoy tank – engineering fast tank). During 1934, one BT-2 was modified by removing its turret and replacing it with an armored box-shaped casemate. Additional bridge-carrying equipment was also added to the hull.

First SBT prototype with a superstructure. Soljankin, A.G., Pavlov, M.V., Pavlov, I.V., Zheltov, I.T. Tom 1. Otechestvennye bronirovannye mashiny. 1905–1941 gg. [Domestic Armoured Vehicles, vol. 1, 1905–1941.] M.: OOO Izdatel’skij centr ‘Eksprint’, 2005, 448 s.: il.
In 1936, the project was modernized by adding a small turret, initially taken from the T-26 twin-turret version tank, which was replaced with a T-38 light tank turret. It also received improved bridge-caring equipment. According to S. J. Zaloga (BT Fast Tank), some 51 BT-2 tanks would be used in this configuration. But, according to Russian authors Solyankin, Pavlov and Zheltov, only two prototypes were ever built.

An SBT based on the BT-2 that had its turret replaced with a T-38 tank turret, second prototype. Source: Pinterest

BT-2 with underwater tank driving equipment (BT-2 PKh)

Generally, the BT-2 PKh (PKh or ПХ in Russian stands for ‘podvodnogo hozdeniya’) was not a modification of the serial BT-2 tank, but an experimental optionally mounted equipment which allowed for deep fording.

The BT-2 PKh was developed in 1933-34 at Factory No 183. The equipment was tested in the Belorussian military district. The testbed BT tank managed to cross a 4 m deep ford. It took 1.5 hours to prepare the tank for the deep fording by the crew of three.

The fording equipment was not adopted into service with the RKKA or approved for serial production. However, it was tested and served as a basis for future experiments with other models, such as the T-26, T-28, and others.

The BT-2 PKh tank differed from the serial BT-2 due to the special devices that ensured the hermetic sealing of the hull, as well as provided the air supply and the removal of exhaust gases.

BT-2 PKh from the left side. Note the tube on the turret, which was used for air intake, as well as a way for the crew to escape in case of sinking. Source: Domestic Armoured Vehicles, vol. 1, 1905–1941

BT-2-IS early prototype

In the spring of 1934, a group of enthusiastic engineers led by Nikolai Tsiganov started working on a new tank, the BT-2-IS (IS stood for Iosif Stalin). The major goals of the project were to improve its driving performance, survivability, and cross-country capability.

The main feature of the BT-2-IS tank was its completely redesigned running gear. The first pair of wheels remained steered, but the pairs from second to fourth became driving wheels. As a result, the turning radius was halved to 5-6 meters, and cross-country ability on wheels was increased four to five times. Only one prototype was built and tested in 1935, with generally positive results. Tsiganov continued to work on the BT-5-IS.

The BT-2-IS prototype. Source: http://icvi.at.ua/forum/763-407-1

Surviving tanks

Today, there are no complete BT-2 vehicles left. In Russia, there are at least three surviving turrets that were used as stationary bunker emplacements. One can be found in the Museum of Military Archeology Petrovsky Island at St. Petersburg. A second is at the Siege of Leningrad Museum. The third turret was placed on a BT-5 chassis and can be seen at the Kubinka Military Museum. Some 5 turrets that were used on the Finnish Salpa defense line, also surviving to this day.

One of the surviving BT-2 turrets was placed on a BT-5 chassis. Source: https://imgur.com/a/qxZtxkx http://tank-photographs.s3-website-eu-west-1.amazonaws.com/BT5-soviet-light-tank-ww2.html

Conclusion

The BT-2 is often criticized by historians for its poor design, mechanical unreliability, a multitude of technical deficiencies, and flawed performance on the battlefield. While the majority of these problems may seem really significant, historians frequently ignore the fact that the positive factors outweigh the negative ones.

First of all, the early BTs were an off-the-shelf weapon system ready to be quickly put into serial production. Secondly, the BT-2 became a valuable asset for the Red Army as a testbed for the new generation of Russian engineers and technicians. The experience gained while working on the BT-2 tanks was really invaluable. It gave the Soviet engineers the necessary experience in tank design, which would eventually lead to the development of far more sophisticated and successful models like the BT-5, BT-7, and T-34 series.

Moreover, having a relatively simple armored vehicle helped to train hundreds of Soviet tankers in the early 1930s. When the newer models started arriving in the Red Army in increasing numbers, there were trained instructors able to share their knowledge and experience.

Perhaps the most outstanding fact concerning the BT-2 is that an armored vehicle with such capabilities or ‘fast tank’ had not even been considered by Soviet theoreticians during the early stages of the Deep Battle doctrine evolution. Adoption of the BT-2 gave impetus to the further development of the Deep Battle. Eventually, combat units armed with fast moving tanks became striking arms of the large mechanized formations and, to some extent, could be considered as a benchmark of the novel Russian doctrine in general.

One could easily conclude that the BT-2 became one of the armored vehicles that determined the way Soviet and ultimately Russian tank-building schools developed, as well as the priceless part of the learning process for the whole army.

From its first actions in Poland in 1939 to fighting in fierce battles during the Great Patriotic War between 1941 and 1943, the BT-2 has proven itself as a versatile and effective weapon system that passed the test of time. Despite all the criticism coming from modern researchers, the BT-2 indeed has earned its place among other legendary armored combat vehicles of the Red Army.

Technical Specifications

All specifications are given for gun and machine gun versions of the BT-2 tank with a cylindrical turret (without a bustle) as of June 1939.

BT-2 specifications

Gun version Machine gun version
Dimensions (L-W-H), m 5.5 x 2.23 x 2.17
Full weight (combat ready), tons 11
Loading weight, tons, without crew, fuel, oil, water and ammunition 10.4
Road Clearance, m 0.35
Crew 3 2
Armament 1 x 37 mm gun;
1 x 7.62 mm DT machine gun in a ball mount;
2 x 7.62 mm DT machine guns in a twin-mount
1 x 7.62 mm DT machine gun in a ball mount;
Ammunition 92 AP and HE rounds, 2,709 rounds of MG ammunition in 82 drums 5,166 ammo rounds in 43 drums
Gun elevation -5° to +21°
Armor, mm Front, rear, sides, turret – 13
Roof – 10
Bottom – 6
Engine 400 hp (294 kW) 12 cylinder Liberty L-12 or M-5
Fuel capacity, liters 360 in two fuel tanks
Fuel consumption, kg / hour 30-60 depending on road conditions and type of terrain
Gearbox Christie type, 4 forward and one reverse gears
Maximum speed on tracks, km/h (road) 50
Maximum speed on wheels, km/h (road) 70

Sources

The Author of this article wants to thank the co-author Alex Tarasov, without whose help this article would have been impossible. Additional thanks to Patryk Cichy for some translation work and to Francis Pulham for allowing to use some of his BT-2 pictures.

BT-2 model 1932
BT-2 model 1932, 37 mm (1.46 in) gun only.
A BT-2 1932 model, twin machine-gun variant
A BT-2 1932 model, twin machine-gun variant.
BT-2 of the reserve force, 1940
BT-2 of the reserve force, 1940.
BT-2 in the Winter war, Karelian front in eastern Finland
Winter war, Karelian front in eastern Finland, December 1939.
A BT-2 during the battle of Moscow, winter 1941/42
A BT-2 during the battle of Moscow, winter 1941/42.

Books and Publications

  • S. J. Zaloga (2016) BT Fast Tank, Osprey Publishing.The Soviet-
  • Finnish War, 1939-1940 Getting the Doctrine Right, Monograph by Major Gregory J. Bozek (1993)
  • L. Ness (2002) World War Two Tanks, Harper Collins Publisher
  • D. V. Glantz (2005) Soviet Military Operation Art, Franck Cass.
  • M. Свирин (2008) Самоходки Сталина. История советской САУ 1919-1945, Эксмо
  • MAJ Nicholas J. Kane US Army, Tukhachevskii to Gerasimov:
  • The Evolution of the Russian Way of Warfare into the Information Age
  • J. F. Milsom, (1981) Russian BT series, Profile Publication.
  • S. J. Zaloga and J. Grandsmen (1984) The Soviet Tanks and Combat Vehicles of World War Two.
  • Surviving BT series tanks, May 2020.
  • D. Nešić, (2008), Naoružanje Drugog Svetskog Rata-SSSR, Beograd
  • T. Bean and W. Fowler (2002) Russian Tanks of World War Two, Ian Allan Pub
  • Pavlov, M.V., Pavlov, I.V., Zheltov, I.G. Tom 1. Soviet Light Tanks. 2007, Tseikhgauz [Russian: Павлов М.В., Павлов И.В., Желтов И.Г. (2007) Советские легкие танки 1920-1941, Цейхгауз.]
  • G. Forty (2005/2007) The Illustrated Guide To Tanks Of The World, Annes Publishing.
  • Soljankin, A.G., Pavlov, M.V., Pavlov, I.V., Zheltov, I.G. Tom 1. Otechestvennye bronirovannye mashiny. 1905–1941 gg. [Domestic Armoured Vehicles, vol. 1, 1905–1941.] M.: OOO Izdatel’skij centr ‘Eksprint’, 200
  • Pavlov, M.V., Pavlov, I.V., Zheltov, I.T. BT Tanks , M. Eksprint, 2001 – 184 p. War Museum series.
  • Ken ON. Mobilization Planning and Political Decisions (late 1920 – mid-1930s). Sankt-Peterburg: Izd-vo Evropeiskogo universiteta v Sankt-Peterburge Publ.; 2002. 472 p. (In Russian)
  • Habeck, Mary R. Storm of Steel: The Development of Armor Doctrine in Germany and the Soviet Union, 1919–1939. Cornell University Press, 2003.
  • Hofmann G.F. A Yankee Inventor and the Military Establishment: The Christie Tank Controversy // Military Affairs. 1975, February. Vol. 39. № 1. P.
  • Mikhail Svirin, Tanks of the Stalin’s Era. Encyclopedia ‘The Golden Age of the Soviet Tank Building’, Moscow. Yauza, Eksmo, 2012, Page 108 [Russian: Танки Сталинской эпохи. Суперэнциклопедия. «Золотая эра советского танкостроения»]
  • A. Shirokorad. ‘Encyclopedia of the Domestic Artillery’, Minsk, Harvest, 2000
    Сборник – KhKBM, 2007
  • Magazine Bronekollektsiya No 1, 1996. Light tanks BT-2 and BT-5. [Russian: Бронеколлекция №1 1996. Легкие танки БТ-2 и БТ-5]
  • Igor Shmelev. The History of a Tank (1919-1996) An Illustrated Encyclopedia. [Russian: История танка. 1916-1996. Энциклопедия техники. Шмелев Игорь Павлович]

Archives

  • RGAE. F. 4372, Op. 91, D. 519, L. 67—42, 39. Signed copy.
  • RGAE. F. 2097, Op. 1, D. 1073, LL. 9—10 (with rev.). Original.
  • RGVA F. 31811, Op.1, D.1, ll. 11-12
  • RGVA, F. 31811, Op. 1, D. 7, LL. 1–2 s ob. Protokol #29, ‘O sisteme tanko-traktoro-avtobrone-vooruzhenija RKKA, 1 avgusta 1929 goda’ [Minute #29, ‘On the system of tank-tractor-auto-armoured weapons of RKKA’, 1 August 1929].
  • RGVA F 31811, O 1, D. 107, LL 5-7 [Russian: Справка об организации и применении высших механизированных соединений в армиях иностранных государств]
  • RGVA F. 31811, O. 1, D. 38, L. 236
  • RGVA F.4, O.1, d. 761, ll. 232-33, “Protokol No.16 zakrytogo zasedaniya RVS SSR”, 9 March 1928”
    GA RF. F. R-8418, Op. 6, D. 45. LL. 141—145. Original
  • RGVA F. 31811, O. 2, D. 1141
  • TsAMO F. 81, O. 12040, D. 372
  • RGVA F. 34014 O.2 D.858. Отчет по весовым данным танкового вооружения.
  • RGVA, F. 4, O. 14, D. 2631, LL. 138–45. Document is dated 27 May 1940. Sistema vooruzhenij 1940 – Postanovlenija Glavnogo voennogo soveta RKKA o sistemah vooruzhenija RKKA [The system of armaments 1940 – Resolutions of the Main Military Council of the Red Army on systems of armaments of the Red Army].
  • TsAMO, F. 229, O. 0000157, D. 0014, P 718
  • RGVA, F. 4, Op. 14, D. 628, LL. 8-16. Original. – 10 May 1932. — A Summary of the Headquarters of the Red Army based on the materials of the Directorate for Motorization and Mechanization of the Red Army on the progress of the implementation of the armored weapon system. [Russian: Заключение Штаба РККА по материалам Управления по моторизации и механизации РККА о ходе реализации бронетанковой системы вооружения]
  • RGVA, F. 31811, O. 2, D. 1083. A report on all tanks received from industrial plants for the period from 1931 to March 1, 1940

Internet Sources

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