Monday, 1 April 2013

Vostretsov's Steel Balls

The path of a technology's development is rarely linear. This is true for any country, at any time. Sometimes, when reading the source material, one can only marvel at the brave and unconventional decisions made by some engineers.

Searching and creativity did not stop when it was obvious that there was nothing to search for. By the 1940s, the "classic" shape of a tank already formed. Tracks, armament in a rotating turret, the layout of the fighting compartment, all of these things were more or less accepted as standard. It would appear at first glance that there is no point in anything new. Deviation from this direction seemed amusing, and unacceptable for a serious engineer.

A negative mind-set towards unconventional solutions was firmly cemented when the Central Committee of Defense of the USSR was flooded with non-viable ideas and proposals. Engineers were tired of shoveling tons of "blueprint ore" and did the same thing civilian engineering bureaus do when they receive a design for a perpetual motion machine: discard without reading.

No one knows why Engineer Third Grade N. M. Vostretsov's idea did not meet the same fate. The mail regarding his project has not yet been found. Perhaps it is still waiting for a patient investigator, somewhere in the depths of CAMD. Additionally, few documents exist regarding combat vehicles ShT-1A and ShT-2, the only remaining Soviet examples of the curious spherical tank. They were built, tested, and even saw combat.

Nikolai Mihaolivich Vostretsov was born on May 2nd (May 16th by the new style), 1904 in Orenburg. His father was a foreman at the textile manufacturing plant owned by the merchant Dolohov. His mother died when he was 3. His father, whose job it was to raise the boy, frequently took him to work, showed him how the various mechanisms work, inspired a love for technology, expecting him to continue the family dynasty. Vostretsov-junior showed aptitude for the hard sciences, and, if not for the October Revolution, may have followed in his father's footsteps. When the country was engulfed by civil war, his education ended. His father, showing no love for the Reds, left the city in 1919, and traveled West, through the territory controlled by Imperial Russian admiral Kolchak. This decision led to a tragedy. On a late April evening, close to the Novo-Troitskiy estate that the father and son were riding to, they encountered a scout group of Kolchak's 4th Corps. Mistaking the travelers for enemy scouts, the cossacks attacked. Nikolai's father was trampled by a horse, Nikolai himself received a wound from a nagaika. He fell off the cart, rolled into the bushes, and ran as far as he could through the forest, until he collapsed. After that, he walked back in the direction of Orenburg for 3 days, and stumbled on a Red Army camp. He was sent to a hospital and received bad news: his left eye was irreparably damaged.

Until the end of the war, Nikolai lived alone in an old apartment, making a living by working odd jobs. After the war ended, he sold what little he had, and left to Moscow, to seek a better life. He worked at the Mytishi factory, studied at the Workers' Faculty, and later at the Leningrad Polytechnical Institute. In 1936, he returned to the factory, and work as an engineer. Despite his injury, Nikolai managed to enroll part-time at the Academy of Mechanization and Motorization of the RKKA.

In 1939, he was transferred to the construction bureau of the KIM automotive factory in Moscow, where he designed light tanks. Thanks to his stubbornness, flexible mind, and high technical competency, he quickly obtained a rank of Technician Second Class.

In 1940, he submitted a proposal for a medium tank, codenamed "Sphere". The tank was very unusual. Its hull had a spherical shape, was propelled by two ribbons made of metallic and rubber links with spikes for better traction. The Sphere was equipped with a 76 mm gun in the upper part of the hull. The vehicle was propelled by two M-17 gasoline engines, just like the ones on the BT-7.

As mentioned above, the Sphere was unexpectedly approved. However, since the vehicle was very unorthodox, it was not assigned to a major factory. The development team, led by Vostretsov, headed to Vyksa, close to Gorkiy (the name of Nizhniy Novgorod from 1932-1990).

In April of 1941, a trial model of the Sphere was built out of mild steel. It drastically differed from the original project. First, the use of a ribbon was deemed impractical. Instead, the tank received two thick tracks that covered its circumference. The tracks were mounted to guides, and could be removed if necessary. Without them, the tank retained the ability to move, but lost maneuverability and off-road performance. This disadvantage was negligible, since the Sphere did not become immobilized after losing its tracks, like a standard tank.

The armament also changed. Instead of a gun turret on top, the tank received a machine gun turret, like on a T-28. L-10 guns were installed in sponsons on the side of the tank. The inability to fire in a 360 degree arc was compensated by doubled firepower. Since the Sphere was very maneuverable, it was not difficult to rotate and aim both guns at the target.

The balancer system was very original. The Sphere was very stable, since it was gyroscopically balanced. However, when making sharp turns, there was a danger of flipping over. In order to avoid this, Vostretsov developed a ballast system, in the shape of a 4-ton pendulum, that always pointed down, no matter how tilted the tank became. Two balancers of smaller mass were placed in the sponsons. The construction worked fairly reliably.

Instead of the gasoline engines, the Sphere used a more optimal V-2 diesel.

Field tests showed that the tank was very good on off-road terrain. The tank was easy to maneuver, spun in place like a top, and easily traversed trenches, valleys, and pits. With enough speed, the tank could literally leap up a barricade of up to 1.2 meters.

However, there were many downsides. The track guides were prone to deformation due to being made of an improper grade of steel. The ventilation system worked poorly, the tank's moving floor had a tendency to jam. Nevertheless, the Sphere was accepted for additional trials, and given the index ShT-1A.

After the start of WWII, the Sphere project slowed down. The team could not obtain enough resources. However, they did not stop. During this quiet period, the expensive L-10 was replaced with an F-34 gun, like on the T-34. In mid-1942, Vostretsov decided that this project must be put aside for another spherical tank: the 35 ton ShT-2T.

The tank was 15 tons heavier than its predecessor. Its armour was thicker, and it was larger. While it was still classified as a medium tank, it had more in common with heavy vehicles, prompting the "T" in its name.

The ShT-2T was meant to be an assault tank, meant to break through enemy fortifications. It was not surprising that its armament was two 152 mm Model 1937 ML-20 howitzers. These powerful guns could be fired on the move; the balancing system successfully dampened the recoil. The gunner was inconvenienced by this, though, since his seat would swing up to almost a vertical position with every shot.

Field tests of the ShT-2T started in July of 1943, along with the final modification of the ShT-1A. The latter was equipped with the D-5S gun, developed by F.F. Petrov. Despite the greatly increased firepower. Vostretsov knew that two projects at once were not feasible, and chose to delay ShT-1A until better days.

After trials and modifications, the ShT-2T was sent to combat trials. On August 10th, 1943, the tank was loaded on a railroad platform and sent to Chernigov, to participate in a large scale offensive. In order to maintain secrecy, the tank was enclosed in a plywood box, and the associated documents described it as a new kind of barrage balloon with a rigid hull.

The tank went into battle supported by an independent special tank company of the 2nd Tank Army. The plan was that the vehicle be first used in a secondary operation, but plans changed. On September 12th, 1943, a German unit composed of two companies of motorized infantry, six PzIV tanks, and a StuG flanked the Soviet advance. Nobody was in a position to intercept them, except the company with the ShT-2T. Reinforced with a weary infantry company, the Soviets engaged the Germans near the Gruzdevka village.

The spherical tank confused the Germans. They even temporarily ceased fire. The tank accelerated, and stormed through enemy infantry with two T-34s. The Germans did not have time to turn their anti-tank gun, as the spherical tank was already within 50 meters of their positions. Two shots from its howitzers disposed of the gun's crew. While the guns were reloading, the Sphere burst through the German lines, spraying infantry with MG fire. Nearly an entire company turned and fled.

A PzIV opened fire at the Sphere, but the shell bounced off the curved armour. The ShT turned and fired. The German tank, with no regard for the road, hit full reverse. It may have gotten away, if not for one track falling into a pit. The tank's hull was stuck on the ground. For a few seconds, the tank twitched, attempting to get free. Then the ShT-2T fired again. One shell missed, while the other took off the PzIV's turret.

The regrouped Germans opened fire at the Sphere from all weapons. Veterans of the special company remember that even machine guns were turned on it. The armoured hull sparked from bullets bouncing off. A shell took off the right sponson, disabling the gun. Here is where the two-gun layout proved fortunate; the driver synchtonized a sharp turn with the gunner, and took out another AT gun crew.

The ShT-2T demonstrated its effectiveness. The NKTP of the USSR received a request to mass produce the Sphere for the army. However, it was declined. A special factory was needed to build Spheres.

Vostretsov was shocked. He became withdrawn, but continued work. In January of 1944, Nikolai Vostretsov caught the flu. The engineer's health, compromised by illness, stress, and poor nutrition, did not hold. Meningitis followed the flu. Despite the doctors' efforts, Vostretsov died on February 8th, 1944, in Gorky.

After the engineer's death, blueprints were found for an "Object Sphere". The 55 ton vehicle was to be an alternative to the IS tank. It had two 122 mm guns, accelerated to 60 kph, and was capable of traveling underwater. Sadly, this tank remained on blueprints.

Original article available here.

Note: most, if not all of you, probably realized that this is an April Fool's joke by Wargaming. However, the first part of the article is true. A massive number of non-viable designs for tanks, including spherical ones, were submitted. Here are some of those, in spherical, or almost spherical, form factors.

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