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T-34 - Development

The T-34 is the first mass Soviet medium tank. In the 1930s there were two extremes in the domestic tank building. On the one hand - BT (bystrokhodny tank / high-speed tank) tanks had speed, mobility and maneuverability, but on the other hand had a weak defense against shells and low fire power of the established weapons. The opposite extreme was represented by heavy tanks with strong armor and powerful weapons, but at the same time slow and slow-moving. The T-34 combined the maneuverability of a light tank with a high level of body armor and powerful armament at the level of a heavy tank. In 1931 the Russians bought two M1931 Christie tanks from the US Wheel Track Layer Corporation in the United States. First brought to the Soviet Union as a turret-less example under the designation of “farm tractor”, the Christie and subsequent Spanish variants provided a basis for Soviet designer Mikhail Koshkin. The Russians copied these, built Christie tanks, and eventually incorporated the Christie suspension system into the T-34. The first Russian Christies had the same engines as the U.S. Christie - a Liberty 12-cylinder V-type of 338 horsepower with forced-water cooling.

The wheel-track system 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. On the basis of the imported Christie vehicle, a whole family of high-speed tanks was mastered in the Soviet Union. In the 1930s, the machines of this series were modernized and improved; the serial models carried the BT-2, BT-5 and BT-7 indices. Of course, the BT-7 and T-34 are tanks of different classes. The difference in the combat mass of them is very large - 13.8 tons for BT against 30 tons for “thirty-four”. However, first, for the first manufacturer of the T-34 Kharkov Locomotive Plant named after the Comintern, the BT-7 was the previous “old” and the T-34 followed by the “new” base model - the “thirty-four” replaced the BT at the same production capacities. Secondly, both the BT series before the war and the T-34 during the war were the most massive tanks of the USSR Armed Forces. Third, the T-34 inherited from BT a general layout. Fourth, it was in the later releases of the BT-7 that the B-2 diesel engine first appeared, which will be installed on all T-34s. The BT series before the war and the T-34 during the war were the most massively produced tanks of the USSR Armed Forces.

The participation of Soviet tankers in the Spanish Civil War made it possible to test these tanks in real combat conditions. On July 18, 1936, the national-revolutionary war of the Spanish people against the fascist rebels began. At the request of the revolutionary government, the Soviet Union sent military advisers and volunteers (pilots, tankmen, sailors), as well as weapons and other materials, to help it. 362 tanks were sent (according to other data - 347) BT-5 and T-26. The rebels were assisted by Nazi Germany and fascist Italy. The first sent to Spain its light tanks Pz. 1 and Pz. II, the second - tankettes - CV3 / 35.

Soviet machines demonstrated a confident superiority over the enemy’s tanks. But both of them were “thin-skinned”, as it was then said, and they suffered unreasonably heavy losses from the fire of 25-, 37-, 40-mm anti-tank guns and even large-caliber machine guns. Conclusions were made. First of all, the light BT was too vulnerable to enemy fire, because its armor was designed primarily for anti-bullet protection. Second, the wheel-tracked propulsion left much to be desired. Third, a gasoline engine in a battle is more dangerous than a diesel engine - when a shell hits, the gasoline tank ignites incomparably faster and stronger than the diesel fuel tank. These are the most important lessons learned on the battlefields of Spain.

The Armored Armored Directorate (ABTU) of the Red Army issued to the Kharkov plant a technical design assignment for a medium tank, originally bearing the designation A-20 or BT-20 on 13 October 1937. It was originally planned that the new tank with the combat weight increased from 13 to 19 tons and the new B-2 diesel engine will retain the wheel-tracked undercarriage type, as in the old BT models.

Working on the A-20, M.I. Koshkin came to the conclusion that in order to increase the thickness of the armor, the power of the armament, and increase the maneuverability off-road, it was necessary to abandon the wheel-tracked scheme of the chassis in favor of the tracked one. Koshkin had many influential opponents who advocated the preservation of a wheel-tracked propulsion unit. Koshkin’s several colleagues and tank designers were arrested by the NKVD as enemies of the people.

In order to evaluate the advantages of a particular scheme in practice, it was decided to design two prototype tanks — the wheeled / tracked A-20 and the tracked A-32 with a combat weight of 19 tons and an armor thickness of 20-25 mm.

The A-20's 8×6 wheel convertible drive was similar to the BT tank's 8×2 and allowed it to run on wheels without caterpillar tracks. This feature had greatly saved on maintenance and repair of early Soviet tank tracks, and allowed the high road speeds.

These two projects were discussed at a meeting of the Defense Committee on May 4, 1938, in which I.V. Stalin, members of the Politburo, the military and designers were present. Tank engineer A.A. Vetrov, a participant of battles in Spain, in his report based on personal combat experience, spoke in favor of a tracked tank - the wheel propulsion proved to be unreliable and difficult to repair. Vetrov was actively supported by Koshkin - he emphasized that the tracked design is less metal-intensive, simpler and cheaper to produce, and, therefore, the scale of mass production of tracked tanks at equal costs will be much larger than the production of wheeled and tracked.

At the same time, there were supporters of the wheel variant - the commander of the ABTU, Commissar D.G. Pavlov and other speakers actively campaigned for the usual wheeled-tracked tank.

The "tracks versus wheels" debate never went away, and bedeviled American armor designers half a century later. But it is important to unpack the nature of the debate in the 1920s and 1930s. During the Great War, the mechanizal reliability of tanks was quite low, and the vehicles typically broke down after running only a few dozen miles. So the armor mobility problem was two-fold - manuevering on the battlefield, where tracks were superior, and transportation to the battlefield, where they left much to be desired. Christie's track/wheel combination provided wheels for transport to the battlefield, and tracks that could be mounted upon arrival at the field of battle.

The result of the meeting was summarized by Stalin, who proposed to build and test tanks of both types. So, in 1938, prototypes of two tanks, differing in the type of propulsion, the wheeled tracked A-20 and tracked A-32, were put to the test. The dimensions of the hull, powertrain and turret of these tanks were the same. But the chassis A-32 has already received five road wheels, like the future serial T-34. Initially, the comparative tests of the A-20 and A-32 did not reveal clear advantages of either scheme.

During trials, Mikhail Ilyich Koshkin argued that, by eliminating heavy wheel gearboxes, it was possible to increase the thickness and weight of the tank’s armor, the power of the mounted weapons. Tracked propulsion can make the tank better protected and armed. At the same time, on a wheeled course the tank catastrophically loses patency in off-road conditions.

In September 1939, members of the government - K.E. Voroshilov, A.A. Zhdanov, A.I. Mikoyan, N.A. Voznesensky Design Bureau, headed by Koshkin, presented the second modified model of tracked A-32. A light graceful tank easily overcame all obstacles, ford crossed a river, climbed a steep steep bank, easily knocked down a thick pine tree. There was no limit to the delight of the audience, and N.V. Barykov, director of the Leningrad Kirov Plant, said: “Remember this day - the birthday of a unique tank”.

In the autumn of 1939, in Kharkov, they began to build two prototypes of the improved tracked tank A-34, which differed from the A-32 in thickness of 40-45 mm armor. It was the maximum possible for the existing engine and chassis. Such armor increased the weight to 26-30 tons and confidently protected the machine from anti-tank guns with a caliber of 37 and 45 mm. A significant improvement in the security of the novelty was possible only thanks to the track-type propulsion unit.

An important role in the birth of the T-34 was played by the creation of a new generation engine. Kharkov designers K.F. Chelpan, I.Ya. Trashutin, Ya.E. Vikman, I.S. Ber and their comrades designed a new 12-cylinder V-twin diesel engine B-2 with an output of 400-500 hp. The motor was distinguished by a progressive timing scheme for its time. In each cylinder head there were two camshafts (as in modern machines). The drive was carried out not by a chain or a belt, but by shafts - one for each head. The timing shaft transmitted torque to one of the camshafts, which in turn rotated the second camshaft of its head with a pair of gears. An interesting feature of the B-2 was the dry-sump lubrication system, which required an additional oil reservoir. It should be added that B-2 was an original design, not a copy of any foreign model. Is this set of technical solutions designers could borrow from existing piston aircraft engines.

According to the results of the tests, on December 19, 1939, the Defense Committee of the Council of People's Commissars of the USSR decided to assign the T-34 name to the A-34 prototype, to adopt it with the condition of refinement: increase the main armor to 45 mm, improve visibility, install a 76 mm cannon and additional 7.62 mm machine guns. The T-34 was nominally accepted for production on 19 December 1939, but Voroshilov had pulled a fast one. He had approved the A-32 for production, but since the T-34 was a “new machine,” it had to go back and start all over in the acceptance cycle. Their first obstacle was having to build 11 tanks for factory and service testing before full permission was granted for production.

A comparative test was scheduled to be reviewed by Comrade Stalin in Moscow on 17 March 1940. The production of two prototypes of the T-34 was just completed, the tanks were already driving under their own power, all the mechanisms worked for them. But the speedometers of machines just counted the first hundreds of kilometers. According to the then applicable standards, the mileage of tanks allowed to be shown and tested was to be more than two thousand kilometers. In order to have time to run in and wind the necessary mileage, Mikhail Ilyich Koshkin decided to overtake the experimental machines from Kharkov to Moscow under its own power.

In one of the truly heroic demonstrations of confidence of all time, Koshkin and a select crew from the Kharkov factory drove 1,250 miles from Kharkov to Moscow in twelve days. It was a risky decision by Koshkin to take the tanks through public land, since the NKVD secret police could have deemed this revealing state secrets. But the tanks arrived on schedule and without major incident, having driven on a secret route through snowbound forests, fields and rough terrain. The two T-34 tanks suffered no major breakdowns, this was in the dead of a very nasty winter. Also present was one of the KV tank prototypes. The competition between the two tanks was never in doubt. Koshkin had demonstrated that the T-34 could maneuver both on the battlefield, and to the field of battle, rendering the complicated Christie track/wheel combination unnecessary.

In March 1940, the pre-production T-34 tanks were tested at the range in Kubinka near Moscow. Impressed by what he saw, Stalin affectionately dubbed the tank “little swallow”, and its start in life was assured. On March 31, 1940, the Defense Committee of the SNK ordered the serial production of a combat vehicle to begin immediately. By the beginning of the War, 1066 T-34s had been manufactured. On the basis of this tank, self-propelled artillery mounts Su-122, Su-85, Su-100 were manufactured, and other equipment was manufactured on its chassis, including the OT-34 flame-thrower tank. On 31 March, a resolution was passed ordering the T-34 into full series production.

This triumph was marred, however, by the death of 42-year-old Koshkin, who had caught pneumonia during the arduous drive to Moscow. Mikhail Koshkin died on 26 September 1940 from complications brought on by the case of pneumonia he contracted during the ride through the snow.

In September 1940 T-34 was put into series production mounting a 76mm gun. The T-34 had been put into production and accepted for service before the official trials were completed. The trials were carried out simultaneously with preparation of relevant production facilities at the Kharkiv Locomotive Plant. The T-34 became the most numerous tank of the the Great Patriotic War, being manufactured at six plants. The tank was continually improved during its production.

In September 1940, the chief of the Main Armored Vehicle Directorate — GBTU — was replaced with D.G. Pavlov, a former BT tanker and critic of the T-34, . Pavlov was pro-T-50 and anti-T-34, and was among those who “requested” the Kharkov design bureau begin work on an “improved” T-34 which looked more like the T-50 than anything else. Problems with early T-34s did not help their cause, and the demand grew for the new tank, the T-34M. While factory director Maksarev and the head of the Kharkov Communist Party showed what had been done to improve the new tank, a new directive dated 5 May 1941 concentrated its efforts on forcing them to focus on the T-34M. The beginning of Operation Barbarossa by the Germans on 22 June 1941 stopped the plans cold.

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Page last modified: 10-04-2019 10:17:07 ZULU