Monday, 26 July 2021

From the Teplokhod AN to the MS-1

The 1920s were a transitional time for worldwide tank building. The end of the First World War resulted in a radical decrease of military budgets. Many vehicles were created as designers and commanders ruminated on the experience from the previous war, but most of them remained prototypes.

Italy joined the tank builders' club with its Fiat 3000 light tank, as did Sweden (with what really were German tanks). The USSR continued to develop tanks as well. The Russian Renault, a copy of the Renault FT, was followed by an original tank: the T-18, aka MS-1.

In search of a suitable solution

Trials of the first Russian Renault tank named Freedom Fighter Comrade Lenin took place on August 31st, 1920. 15 such tanks were built at Sormovo in total. These were the first tanks of the nascent Soviet tank building school.

The military was not satisfied with simply copying foreign tanks. French tank designs were not entirely satisfactory for the battles that raged across the former Russian Empire. The Russian Civil War was quite maneuverable and WWI style tank attacks were rarely possible. Armoured cars were much more suitable. They may have had poorer off-road mobility, but better agility and range.

The Red Army established a classification system for tanks by 1921. Captured Mark V tanks were classified as Category V: breakthrough tanks. The Mk.A Whippet and Mk.B Hornet were classified as Category S: maneuver tanks.

Izhora factory management. Their work meant that the Izhora factory had a chance to build the new tank.

Finally, the Renault FT and Russian Renaults were classified as Category M: support tanks. Drawbacks of these tanks included difficulty in working with the armament, short range, and excess mass that did not allow them to be carried on trucks with 3-5 tons of capacity.

Attempts to develop a domestic tank took place in parallel with work on the Russian Renault. The Military Industry Council (SVP) announced a call for tender for a new tank on November 2nd, 1919. The tank would be armed with two machine guns or one 37 mm cannon: the Rozenberg model 1915 trench gun or Maxim-Nordenfelt autocannon. Both weapons were produced by the Obukhov factory. The machine gun armed tank would be crewed by three men, the cannon armed tank by two. The armour was 9-12 mm thick. The mass could not exceed 700 poods (11,467 kg). The tank was supposed to use automobile components. The expected top speed was 16 kph.

Interestingly enough, large industrial companies did not take part in the tender initially, including the Izhora factory that was building armour for the Russian Renault. Factory management only found out about the deadline. Factory management petitioned the SVP to extend the deadline from November 25th, 1919, to February 1st, 2020. The factory had good reason to ask for an extension, as nothing worthwhile was submitted. The large sums of money that were promised for victory and top runners up attracted a large number of questionable submissions. The deadline was postponed to February 15th.

The Izhora factory submitted a project developed by engineers G.V. Kondratyev and D.S. Sukhazhevsky. Their tank was called Teplokhod (motor ship) AN: an amphibious tank weighing 10,107-10,156 kg.  The tank was supposed to use the FIAT 60 HP engine. The choice was simple: the factory already had 60 of these engines. These were likely the same engines used on the Izhora Fiat armoured car. Alas, only fragments of the project documentation remain. It is known that the vehicle was supposed to be able to move both on land and on water (using a propeller).

Izhora engineers used the experience gained from the Russian Renault tank that was going to be assembled at their factory. The Teplokhod AN had the same running gear design and shared some transmission components. Two variants were offered: one with machine guns and one with the Maxim-Nordenfelt cannon.

The Maxim-Nordenfelt cannon proposed for use in the Teplokhod AN tank.

The Teplokhod AN was announced as the winner on April 2nd, 1920. A decision to end production of the Russian Renault (also nicknamed Lilliputian at the Izhora factory) was made shortly after. A new objective was given: to build two prototypes of the Teplokhod AN, one with machine guns and one with a cannon. These vehicles were also called "Izhorzavod tanks" in documents.

The Izhora factory began developing detailed blueprints on April 19th, 1920, as per orders of the chairman of the SVP. The deadline was set at May 1st, 1921. Engineers N.S. Vlasov, N.Ya. Obukhov, M.S. Sukhorukov, and A.A. Markovsky worked on the tank. Obukhov, an experienced armoured car designer, led the group.

The Izhora factory eventually built an amphibious vehicle. The BAD-2 armoured car was built 10 years after their tank.

Blueprints were still not finally approved by October 1920 due to delays, as the engines had not yet arrived from Moscow. The deadlines began to shift. The first tank was now due on May 15th, the second no later than August 1st, 1921. The Izhora factory began assembling the tanks in late 1920, and they were 25% complete by the end of January 1921. Only the hulls were assembled, as the subcontractors (Obukhov, Putilov, and Sormovo factories) were habitually late. In February the hull of the first variant was 32% complete, the engine was 55% complete, and controls were 20% complete. The second tank was at 28, 50, and 15% respectively. The tanks cost 20 million rubles.

Work on the tanks was delayed more and more. The subcontractors were at fault, but the situation at the Izhora factory was also difficult. There were not enough workers. The deadlines continued to slip. Neither tank was finished in 1921. In July of 1922 the deadline for the delivery of the first tank was moved to February 1923. By then the cost of the tank was reduced to 2.8 million rubles due to currency fluctuations. The first prototype was 50-60% finished in the summer of 1922, the second was 30% finished.

The idea of building the first tank first and then finishing the second after trials was raised in August of 1922, but the Teplokhod AN was already in danger of cancellation. The Main Directorate of Military Industry (GUVP) was running out of patience. The delays meant that the tank was slowly becoming obsolete. Of course, the Izhora factory missed the new deadline on April 20th, 1923. Based on correspondence, the project was abandoned due to a lack of progress by subcontractors, primarily the Obukhov factory.

The order for the Teplokhod AN was cancelled in January of 1925, the freed up resources were used to work on artillery instead. N.Ya. Obukhov moved to other projects. The Izhora factory eventually built prototypes of amphibious vehicles, the BAD-2 and PB-4 armoured cars. The factory no longer tried to design its own tanks.

The first Soviet light tank could have looked like this. This draft is dated June 1924.

The Revolutionary Military Council of the Republic (RVSR) gave order #111/20 on January 13th, 1921, forming a special commission within the Main Military Engineering Directorate. It was tasked with development of tanks and supervision of their production. The commission was headed by senior engineer S.V. Shukalov. The SVP's functions were transferred to the Main Directorate of Military Industry within the Supreme Council of National Economy in August of 1921. It contained the GUVP Technical Department, which was also headed by Shukalov. No work was done between 1921 and 1923 since the GUVP was still being organized. Funding only became available in early 1924. A list of factories that could be used to build tanks was composed. It included the Sormovo, Kharkov, Kolomna, Izhora, Obukhov, and Putilov factories.

Work on the new tank was slowed down by a lack of finalized tactical-technical requirements. The first of the GUVP's tanks were grassroots efforts. The first Category M tank could have been very different from the MS-1. The USSR began economic cooperation with Germany in 1924 and purchased licenses for the Hanomag Z WD-50 tractors. This linked Joseph Vollmer to Soviet tank building. He was already working on a convertible drive tank on the Hanomag Z WD-50 chassis by 1924. Shukalov must have been aware of his work, as in June of 1924 the GUVP presented a light tank that was quite similar to Vollmer's KH-50 or Kolohousenka. Work didn't progress past drafts, but this was the first documented instance of foreign participation in Soviet tank building. Later, design of the M tank went in a different direction.

Less is more

The ambiguous state of Soviet tank building until 1924 didn't mean that the army was not interested in tanks. According to the armour subcommission of the RVSR, 1500 tanks were to be built in 1923-1928. A report issued on March 3rd, 1923, indicated the Putilov factory (Krasniy Putilovets) in Petrograd.

The GUVP had a different opinion. Krasniy Putilovets organized production of Fordson wheeled tractors under license. The GUVP planned to build tanks elsewhere in Petrograd: the Obukhov factory. It was renamed to Bolshevik in 1922 but still often referred to by its old name in correspondence. 

The Obukhov factory already had experience with heavy vehicles. It also assembled tractors, but more serious ones: the Holt 75 and Holt 40. Holt tractors laid the foundation for tank building in the first place. The factory also build artillery, including small calibers. These factors mad the Obukhov factory an ideal candidate for a tank factory.

Holt 75 tractor built at the Obukhov factory, 1922.

A tank had to be developed before it could be put into mass production. A suggestion for a call for tender was made at a meeting of the GAU Artillery Committee. "Special tank engineering cells with 4 engineer-designers and 6 support staff" were to be formed at the Kolomna, Putilov, and Sormovo factories. The Armour Section of the Artillery Committee (as with other nations, tanks were the purview of the artillery branch) did not agree. The poor experience with the Teplokhod AN led to dropping the idea of a call for tender. Instead, work would be concentrated in a separate bureau. Approval of this proposal was a signal for Shukalov's GUVP Technical Design Bureau to start their work. However, there were still no tactical-technical requirements for this tank.

Order to produce an experimental prototype of the "regimental support tank", as the MS-1 was called at the time.

Consensus was reached by the end of 1924. The Tank Commission considered the state of the Red Army's vehicle pool. There were almost no heavy trucks like the kind the French used to transport the Renault FT. Initially the regimental support tank was supposed to weigh 3 tons so it could be transported on more common trucks. Its top speed would be 12 kph, its armour would be 16 mm thick. The armament consisted of a 37 mm cannon or machine gun.

These requirements were too harsh. The GUVP Technical Bureau had a hard time meeting them. The idea of having either a cannon or a machine gun was also not ideal, as the Russian Renault had both for a reason. The proposed support tank was a little outside of the requirements. It weighed 4150 kg, its top speed was 13 kph, and the armament consisted of the 37 mm Hotchkiss gun and two Fedorov carbines in a ball mount.

The Red Army supported the design group headed by V.I. Zaslavsky and the weight limit was raised to 5 tons. The military also set the requirement for both cannon and machine gun armament, as well as higher top speed.

The initial shape of the MS-1's hull. The initial project had a different engine compartment.

The rigid weight requirements led to a very unique vehicle. The new Soviet tank had little to do with the Renault FT. The only remnants of the French tank were the overall concept of a light infantry support tank and some components (even those were adapted). The hull was very different. The initial design was just 3060 mm long, a whole meter less than the Renault FT, at the same height and width.

The biggest similarity was in the front driver's compartment, but even here there were some differences. There were many more in the fighting and engine compartments. Wide bulges to store the fuel tanks were introduced under the turret. The tank was made shorter chiefly due to a very compact engine compartment. A tail was added to help the tank cross trenches. It was similar to the Renault FT's tail, but it was longer.

Cutaway of the engine and gearbox. This was a revolutionary design for the 1920s.

The secret of this compactness was simple. A special engine was developed at the Bolshevik factory. The air cooled 2.18 L 35 hp engine was one of the first to be installed perpendicularly to the tank. Even more unusually, the engine was joined into one unit with the gearbox. The commander could access the engine through a hatch in the engine compartment bulkhead.

A myth associated with the engine deserves a separate mention. A.A. Mikulin is often credited for its design, but this is not the case. He only saw the engine on February 26th, 1927, when it was undergoing trials.

The suspension was both simple and progressive.

The running gear was also original. The only thing in common with the Renault FT was the large idler. Three return rollers and 6 road wheels were used on each side. The wheels were made from aluminium with rubber rims to reduce weight. They were coupled together into bogies with coil springs. The first pair of return rollers was installed on leaf springs. The original stamped track links were fairly wide (300 mm), giving the tank a record low ground pressure.

Without exaggeration, the suspension was revolutionary for its time. Most tanks of the era had a much more cumbersome suspension.

This turret was used starting with the second prototype.

The fighting compartment was also very good for its time. It was 100 mm wider than on the Renault FT. The cannon and machine gun ammunition were stored along the sides. The hexagonal turret was 50 mm wider than the Renault FT's turret and 100 mm lower. The cupola was also wider and lower. The Renault FT used the cupola as an air intake and an observation hatch, but on the Soviet tank the commander could use it to enter the tank as well. An emergency hatch was located in the side of the turret.

The 37 mm Hotchkiss gun and Fedorov machine gun were located in the front turret plates. Either the cannon or the machine gun could be used. The cannon was the primary weapon. When using it, the Fedorov machine gun was taken out of its port and stored on the side of the fighting compartment. Not very comfortable, but other tanks of this time had either a cannon or a machine gun, not both.

A difficult first-born

The technical project was complete by July 10th, 1925. A meeting between Shukalov and the Bolshevik factory management to discuss the possibility of building the tank took place on June 27th. The factory received an order for an experimental support tank in early August at the cost of 25,000 rubles. The money went not just to building the tank, but to finishing development. For instance, the engine still existed only on paper.

The development was done alongside the GUVP Technical Bureau. August 1st, 1926, was established as the due date.

This was not the end of the selection process for a support tank. This is indicated in minutes of a meeting that took place on October 24th, 1925. Chief of the Mobilization Planning Directorate of the Red Army Abraham Mironovich Volpe supported the idea of a domestic tank, but wanted to use a foreign tank as a backup. This meant that such a tank had to be purchased. The Italian FIAT 3000 tank was the most likely candidate. Its characteristics were close to those that the military wanted. The FIAT 3000 was lighter than the Renault FT, more mobile, and its turret was roomier. The tank was only armed with a machine gun. Italy even proposed a sale of 10 such tanks in 1924. This fact was used by some historians to declare the MS-1 a copy of the FIAT 3000, but that is not the case.

The French Saint-Chamond Modele 1921 Chenillette convertible drive tankette was selected as an alternative, but the French were unwilling to sell weapons to the USSR.

Diagram of the FIAT 3000 composed by the GUVP Technical Department. This tank was considered as a backup plan in case the domestic support tank did not pan out.

The technical project for the support tank was approved. Shukalov was instructed to work on using a liquid cooled engine. A choice between the Soviet tank and its foreign analogue would be made in the spring of 1927, after trials.

The harsh deadlines and the possibility of choosing the FIAT 3000 had its impact. Zaslavsky was sent to Bolshevik in November of 1925. The work done by the Bolshevik Technical Bureau was performed by N.N. Magdasiev.

Work on the engine began in late 1925 with N.R. Brilling (the head of the Automotor Scientific Institute or NAMI) acting as a consultant. A second engine with water cooling was designed. Some changes had to be made to the tank due to different dimensions. The track link was also redesigned. A second prototype was ordered in early January of 1926.

The first prototype of the support tank that would later be indexed T-16, February 17th, 1927.

A backup armour scheme was suggested instead of using 16 mm armour plates. "Rozhkov's armour" consisted of two layers, one layer of soft "Krupp steel" and one layer of harder molybdenum steel. A.Z. Rozhkov also designed triple-layer armour.

The prototype would be built with single layer armour to not delay production any longer. Work on the armour continued in the spring and summer of 1926.

Changes were introduced in other parts of the tank in parallel. The mass of the tank had reached 5 tons by May 31st, when a meeting of the expanded Artillery Committee was held. The 37 mm Hotchkiss gun was deemed to have inadequate penetration at the meeting. A "45 mm high power gun" being developed by the Commission of Scientific Artillery Experiments (KoNArtOp) was suggested instead. As work on this gun stalled, this proposal did no go forward. In parallel, an improved 37 mm tank gun that used ammunition from the 37 mm AA gun was suggested.

The same Artillery Committee meeting planned equipping the tank with "universal convertible drive". A "Skoda factory tank" was mentioned, the second instance of Vollmer's influence in Soviet tank development.

Finally, a suggestion was made to build towed equipment to transport the M tank across large distances.

T-16 at the factory. This tank had a different turret and was armed only with machine guns.

By mid-summer it was clear that the deadline for building the first prototype would not be met. A torrent of correspondence erupted. The factory blamed the delay on the new components and other commitments, including work on tractors. The customer suggested October as the new deadline, but factory management indicated December as a more realistic deadline. The factory also asked for permission to build the tank from mild steel, as delays with the armour delayed assembly.

The factory was reminded that 120-150 of these tanks were expected by mid-1929. A backup factory was found to achieve these numbers. 50-75 tanks from prepared parts could be built at the Perm Arms Factory. This choice was made in September of 1926 when the FIAT 3000 was again indicated as a potential opion.

The rear of the engine compartment was also different.

The factory indicated that "All components are finished. The engine is prepared for trials. Assembly has started." on November 13th. The first tank was to be assembled in December, but be fully operational only by mid-February 1927. Successful trials of the "support tank model 1926" suspension took place in late December. Trials of the engine also began in December and were marred by small defects. All components were finished by the end of 1926, all that was needed was to put them together.

Assembly of the first Soviet tank was finished by February 17th, 1927. The tank was very similar to what would later be called the MS-1 with a number of differences. This tank only carried a Fedorov machine gun and it had rigid fenders. The engine compartment was shorter than on the production tank, and a large air intake was located on its top. The running gear changed compared to the project. Another road wheel was added in the front.

Trials of the first prototype, April 1927. Despite the military's requirements, this tank had no cannon.

The first mobility trials took place from March 3rd to March 5th, 1927. The tank was tested in the factory courtyard. On March 5th the tank was weighed. It weighed 4200 kg without armament, ammunition, or crew. The weight requirements were met. The engine worked for three hours during the initial trials. Small faults were discovered and corrected. The tank was disassembled, all the components were inspected, and it was reassembled.

Full scale trials were performed on March 8th. The tank drove towards Izhora and back. In 2 hours and 37 minutes the prototype travelled for 12 km on a highway and 5 km off-road. Since the engine was still being broken in the third gear was reduced, and the maximum speed attained was 6-8 kph. Nevertheless, the first real outing inspired optimism in factory staff. The tractors accompanying the tank could keep up on difficult terrain, but on good roads it took the lead, even though the tank drove on ordinary tracks but the tractors had grousers.

Not a single breakdown was recorded during the trial. The third gear was therefore increased and the tank could reach a top speed of 15 kph. The shock absorber for the from road wheel was changed after the trials..

The tank went through these trials without paint.

The tank smashed a wooden shed during trials.

On March 8th the tank was deemed ready for trials carried out by a commission from the Artillery Directorate. The Red Army had different ideas, and a list of required improvements composed by Shukalov arrived on the very next day. Extra fuel tanks had to be installed, the driver's seat lowered, the running gear redone, and a cannon installed. The cannon was different from the one used on the Russian Renault, in part due to a muzzle brake. The next trials were scheduled for March 29th. Nevertheless, it was already stated that the tank was a success.

The improved prototype. Changes in the rear part of the hull can be seen.

Trials didn't happen in late March, but only from April 6th to April 9th. The tank still had no cannon at this point. An act was composed after the trials in which the commission stated that the tank design was rational and viable. The commission remarked that the tank was highly maneuverable, the crew sat comfortably, the engine worked flawlessly. At the same time, there was a list of 25 items that had to be corrected. The tracks had insufficient traction, the vision slits had to be changed, the tank had to be made waterproof. The cannon and machine guns had to have optical sights. The front fenders and their carriers had to be removable. Additionally, the threading should be changed from imperial to metric on any future tanks.

The front fenders were removed during trials. The tank's cannon was equipped with a muzzle brake, but it turned out to be ineffective.

Most of the changes were introduced during the modernization that was complete by May 14th, 1927. A cannon was finally installed in the turret. A slotted muzzle brake was installed. A bulge was added to the rear that served as an extra air intake.

Off-road mobility trials in the vicinity of Romashkovo village, June 1927.

Two types of muzzle brakes were tested on May 28th. The gun was first tested without a muzzle brake, the recoil length was recorded as 58-60 mm. The muzzle brakes were then tested. It turned out that the recoil length was the same 60 mm. The muzzle brakes were ineffective. It's not surprising that a muzzle brake is only seen on the Hotchkiss gun used on the second prototype tank.

Negotiating a slope.

The modernized tank was sent on a trial run on May 31st. The speed reached 13 kph in some areas. The brakes heated up during the trials. On June 3rd the tank was loaded on a railway platform and sent to Moscow. The tank was accompanied by driver Aleksandr Lundyshev.

The tank underwent trials from June 9th to June 15th. On the 10th the tank navigated an obstacle course twice as fast as a Renault FT. The tank broke through wire obstacles and toppled a telephone pole. It could be loaded on a Leyland 5 ton truck in a minute. The tank had smoother travel than the Renault FT and satisfactory mobility, as it could still cross trenches. On June 11th the tank successfully travelled between Cherepkovo and Romashkovo villages. Its top speed was recorded at 14 kph.

Small defects did not mar the overall picture. The tank was accepted into service.

Despite some minor defects, it was clear that the support tank was a success. It was accepted into service on July 6th as the T-18. To distinguish production tanks from the prototype, the latter was dubbed T-16. The T-18 was also given the name MS-1 (Small Support, 1st model). This tank entered history as the first mass produced original Soviet tank.

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