Friday 24 March 2017

First Soviet Tanks

The first tank built in the young Soviet Republic was the "Russian Renault", a poor copy of the most numerous and probably best tank of WWI. It is also known as "Freedom Fighter Comrade Lenin", after the name of the first tank of the batch. There were 15 Russian Renaults built in total at the Krasnoye Sormovo factory in Nizhniy Novgorod under the supervision of visiting engineers from the Putilov and Izhor factories. This group was headed by Sergei Petrovich Shukalov. The Putilov and Obukhov factories were pioneers of the Russian Empire when it came to mastering complicated machinery, and the Izhor factory specialized in producing armoured plates and parts for the Imperial army.

Tanks were not built in Soviet Russia after the end of the Civil War. The country's industrial capacity was aimed at industrialization and restoration of the ruined agricultural sector. However, the topic of tanks was not forgotten. The Obukhov factory was studying tanks captured by the Red Army from the Whites and interventionist forces. Little by little, fragments of information arrived from workshops in the south of Russia, where the last battles just ended, about the specifics of foreign tanks that local craftsmen repaired for the White Army. The Obukhov factory was entrusted with the repair and service of existing tanks starting in the summer of 1921, as the quality of work at Sormovo was not satisfactory for the military. In 1922, the factory was renamed to "Petrograd State Armament, Optics, and Steel Casting Factory "Bolshevik"". 

T-18 (or MS-1, Small Support) tank on parade. November 7th, 1929

A design bureau was created in Moscow at the Main Directorate of Military Industry, headed by S.P. Shukalov. At first, the bureau designed the T-18 tank (or MS-1), a new modernization of the Renault FT. The T-18 was completed by 1925, and its mass production began in 1928 at the Bolshevik factory.

The army needed a more powerful support tank, and the UMM (Mechanization and Motorization Directorate) created requirements for a new tank with cannon and machinegun armament in rotating turrets. The "Komintern" Kharkov Locomotive Factory (HPZ) was tasked with its design under the supervision of Shukalov's design bureau, which was then renamed to the Armament-Arsenal Trust. The Kharkovites already had experience with civilian tracked vehicles (the Kommunar tractor, based on the German Hanomag WD Z-50). Now they had to learn how to build tanks.

The Muscovites did not try to take over all the work. On the contrary, they loaded off as much of it to Kharkov as possible. Initially, the deputy chief engineer M. Adrianov and deputy tractor plant foreman V. Dudka were responsible for the tank, but a special tank design group was created in 1927 with I.N. Aleksenko at the helm, a young and talented designer who had just returned from serving in the army. Most designers working here were very young. Aleksenko turned 23 in 1927, A.A. Morozov, one of his deputies, turned 23 as well, and most other engineers were even younger.

I. N. Aleksenko: head of the HPZ tank design group from 1927 to 1931. In May of 1929, the specialized T2K design bureau was formed on the basis of the group.

The group began working actively. A tank prototype was ready by October 15th, 1929, but it took two more months to install equipment. The T-12 was influenced by two design schools: the American and the French. The layout was largely borrowed from the M1921 Christie tank, built in 1921 and not mass produced. It rejected the rhomboid layout of WWI tanks had a layout that would soon become classic: driver's compartment in the front, fighting compartment in the middle, engine and transmission in the rear. It was likely that the layout was taken from unclassified sources, such as American popular science magazines, where American designers often published advertisements.

American M1921 tank designed by Christie.

The T-12 had a machinegun was placed in a separate cupola, which was placed on top of the main turret in order to save on space and mass. This created certain issues for the crew and increased the height of the tank, but engineers went to further lengths to save on weight.

The influence of the French school can be seen in the suspension. It almost completely repeats the design of the T-18 (MS-1), which, in turn, was a copy of the French Renault NC-27.

Wooden model of the T-12.

The T-12's running gear consisted of 16 road wheels (8 per side) paired up in eight bogeys (4 per side) with a vertical spring suspension. The tracks were supported by four return rollers. The tank had its drive sprocket in the rear and the idler in the front.

The plan was to equip the T-12 with a domestic engine designed by A.A. Mikulin (a nephew of the father of Russian airplane building, N.E. Zhukovskiy), which would be built at the Bolshevik favtory. Since no engine was built yet, the tank was equipped with the 8 cylinder 240-300 hp M-6 aircraft engine, a licensed copy of the French Hispano-Suiza 8Fb.

A planetary gearbox allowed the tank to reach a speed of 26 kph. The T-12 was equipped with a 690 mm metallic "tail" in the rear, which lengthened the tank and allowed it to cross trenches up to 2.65 meters wide. This trait was inherited from the T-18.

The nonagonal three-man (commander, loader, machinegunner) turret would be equipped with a 45 mm cannon or a 76 mm howitzer. The sides of the turret had two 7.62 Shpagin ball mounts for Fedorov machineguns. The third machinegun was installed in the front of the turret, to the right of the gun. The fourth was installed in the machinegun cupola, which was shifted to the rear from the center.

T-12 in the factory courtyard.

The armour was sufficient for its time: 22 mm in the front, 12 mm on the sides. The hulls of the T-12 and T-24 tanks were built at the Izhor factory. The T-12's driver was placed in the front, towards the right side, which is an unusual feature of Soviet tanks exclusive to the T-12 and T-24.

Trials of the T-12 began on April 2nd, 1930. The tank drove for 2 km off-road, but the transmission soon broke. The engine worked for only 33 minutes before it overheated and the water in the radiator began to boil. When turning on soft soil, the right track slipped off the idler.

The tank was improved, and new trials took place from April 28th to May 2nd of 1930, this time with People's Commissar of Armament Marshal Voroshilov, UMM chief Corps Commander I.A, Khalepskiy, and NTU (Scientific-Technical Directorate) chief G.G. Bokis. The factory was represented by the HPZ director L.S. Vladimirov and the chief of tank production, S.N. Makhonin. Instead of the Fedorov machinegun, which was not yet built, the tank was equipped with a 7.7 mm Lewis machinegun and showed good results: up to 60% hits on target. The tank could easily climb a 35-36 degree grade in first gear, reach a speed of up to 26 kph on flat ground (up to 30 kph if the engine was revved up to 2000 RPM), cross trenches up to two meters wide, and was fairly agile off-road. The ground pressure was 0.45 kg/cm², which was acceptable. Nevertheless, the tank was not accepted into service.

It was already clear by mid-1929 that the T-12 would not enter mass production due to inherent design defects that made it unreliable and gave it a short range (80 km). The HPZ design bureau, which was born out of Aleksenko's design group, was tasked with developing an improved modification of the T-12 in parallel with completion of work on it. This modernized variant was named T-24.

T-24 mod. 1930.

The design of the T-24 was not much different from that of the T-12. The additional fuel tanks were placed on top of the fenders, since there was no room inside, like on the T-18. Another machinegun was installed in the upper front plate, and another crew member was added: the machinegunner, sitting to the left of the driver.

The UMM instructed HPZ to build a batch of 15 T-24 tanks without awaiting trials. The first three tanks were completed by July of 1930, and one was sent to Kubinka for trials. Here, the tank was sent to the proving grounds with full fuel tanks and 10 rounds of ammunition. However, a fire quickly broke out within the engine. The crew left the tank in panic, aside from the driver, Vladimirov, which put out the fire and saved the tank on his own. The tank received minor damage and was sent to be improved further.

T-24 prototype on trials. Neither the 45 mm gun nor Fedorov machineguns were ready, so the tank had to start trials without them.

The nonagonal T-12 turret was replaced with a cylindrical one, and the old turret was returned to the T-12. The new turret had a new experimental 45 mm gun instead of the old 45 mm Sokolov gun, which would go on to become the famous 45 mm tank gun mod. 1932. The machineguns were removed from the sides of the turret, leaving only the machineguns in the front of the hull and turret and in the cupola. Instead of the Fedorov machinegun, which was never finished, the tank was equipped with Degrtyaryev mod. 1929 machineguns. The ammunition capacity of the tank was 89 shells and 8000 rounds.

The mass of the tank grew from 14.7 to 18.5 tons as a result of all the changes, which reflected on its mobility. The top speed dropped to 24 kph. The fuel capacity increased to 460 L, which increased the range by 1.5 times: from 80 to 120 km.

T-24 tank.

After side-by-side trials of the T-12 and T-24 tanks, the UMM made an order for 300 T-24 tanks in 1931. A special T2 wing was built at the factory for tank assembly, and Aleksenko's T2K design bureau was enlarged. However, the UMM Scientific-Technical Committee chief, I.A. Lebedev, tasked the HPZ director with building the convertible drive BT tank. Production of the T-24 was cancelled, and the factory only had time to build 28 chassis, 25 hulls, and 26 turrets (production was behind schedule). 25 tanks were assembled.

Moscow had several reasons to make this decision. First, a purchasing commission headed by Corps Commander I.A. Khalepskiy visited a number of foreign tank design and production organizations, and made deals with some of them regarding licensed production in the USSR. Khalepskiy convinced the People's Commissar of Armament, Marshal Voroshilov, that buying and building Vickers and Christie tanks was a better deal than wasting time dealing with problems that Western designers already found solutions to. History shows that this was the correct decision.

Member of the T2K design bureau at HPZ.

Engineers from Eduard Grotte's design bureau, recruited by the same commission, designed the TG-1 medium tank, a prototype of which was built at the Bolshevik factory in Leningrad. Its armour, armament, reliability, and mobility was superior to that of the T-12 and T-24, as well as that of most Western analogues, and Soviet leaders saw it as the Red Army's future medium tank. The discovery that the tank was too expensive for the Soviet economy and too complicated for Soviet factories was only made much later.

What was obvious in Moscow was met with confusion in Kharkov. According to deputy UMM chief G.G. Bokis, "factory director Bondarenko openly called the fast tank a "saboteur tank" in order to discredit it... it took great efforts, up to contacting the Government, to force HPZ to build the BT tank and correct defects in its blueprints and designs during production."

BT-2 tank.

After pressure from Moscow, work on the future BT-2 tank finally began, but not at the rate that was considered satisfactory by Soviet leaders. Only three tanks were assembled by November 1st, 1931, as opposed to the six that were planned. The new tanks took part in the November 7th parade in Kharkov.

N.I. Aleksenko put in his resignation, with the reasoning that forcing the factory to produce foreign tanks was unpatriotic and harmful to the development of domestic design talent. On December 6th, 1931, he was replaced with A.O. Firsov, the former chief engineer at the "Russian Diesel" factory in Leningrad. Firsov was previously convicted as a saboteur (work in Kharkov replaced five years of camps). This change was pivotal for the factory, Soviet tank building, and the country as a whole.

Firsov brought ideas to HPZ that would later set the stage for the legendary T-34 tank: a diesel engine, which was soon built by Kharkov specialists, and a 76 mm gun as a tank's main armament. The T-34 inherited a welded hull and the Christie suspension from the BT tank. All of this would come later. Meanwhile, the creators of the T-24 were outraged about the changes that came from above, but kept working.

T2K design group, with its leader from 1931-1936, A.O. Firsov, in the middle.

The fate of the 25 T-24 tanks was dramatic. They were not in demand until 1932, when the 45 mm mod. 1932 tank gun was finally accepted into service. By then, the UMM realized that the Soviet T-26 and BT-2 tanks, build on the foundation of the foreign Vickers E and Christie tanks, could achieve the same objectives that the T-24 tanks were built for. In addition, work was underway at the Kirov factory on the multiturreted T-28 medium breakthrough tank, which was superior to the T-24. The T-24 was not accepted into service after all.

18 tanks were sent to the Kharkov Military District (HVO), where they were distributed among training units. One tank was left in the Moscow Military District (MVO) and assigned to the Stalin Military Mechanization and Motorization Academy. Five more tanks were sent to tank and artillery proving grounds. By 1938, most of these tanks were disabled due to breakdowns in the engine, transmission, or suspension.

On March 2nd, 1938, the People's Commissariat of Armament ordered these tanks to be removed from service, partially disarmed, have their armour removed, and have them sent to fortified regions to be used as immobile bunkers (BOTs). Earlier, MS-1 tanks were converted into BOTs. The order was applied to the 22 T-24 tanks in HVO and in warehouses. The Kiev Military District would receive 12 tanks (all from HVO), and the Belorussian Military District would receive 10 (6 from HVO, 1 from MVO, 3 from the warehouse-workshop #37 in Moscow).

The tanks had their engines, transmissions, tracks, and other suspension elements removed. Only the road wheels remained so that they could be towed around. The machinegun cupola, machineguns, and 45 mm gun were also removed. They were replaced with a 76 mm gun (L-10 or KT-28) and a 7.62 mm Maxim machinegun in a ball mount to its right. The driving compartment was radically altered, the front armour was increased, and two more Maxim ball mounts were added. This armoured bunker was not buried in the ground, but towed and positioned in front of a likely enemy breakthrough.

There is no information about how this order was carried out. It's possible that the process was drawn out, since German photographs from 1941 show T-24 tanks converted into BOTs, but not placed into position.

German solder in front of a T-24 BOT, armed with a 76 mm L-10 gun. Leningrad Military District, fall of 1941.

There is information about one complete T-24 tank at the Kubinka proving grounds. In the fall of 1941, it was presumably sent to the front lines.

Artyom Drabkin's book "I Fought in a Tank" contains the memoirs of Hero of the Soviet Union Ashot Aletovich Amatuni, who wrote about the battles in the Salkiye Steppes in the summer of 1942, where he fought as an infantry cadet:

"We marched from the Surovikino station to the front lines... took up defenses somewhere 120-140 km west of Surovikino. Tanks were our most dangerous opponents, since the only method we cadets had against them were bottles with incendiary fluid... We were faced not with light T-II tanks, but medium T-III and T-IV tanks, serious opponents. By the end of the fighting, we were supported by English Matilda tanks and our T-24s, but these were small, bad tanks. Only the T-26 seriously helped us..."

It's unlikely that we will ever learn if the veteran mistook some other tank for the T-24 or is these were indeed T-24s, never converted into BOTs but instead lost in an unfair fight.

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