Unusual Tanks

Gallery opened 14 Apr 2020

Updated 25 June 2020

New picture of Boirault Bridge tank V2: 1916

Index added

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THE TSAR TANK: 1915

Left: The Tsar tank: 1915

A tank is normally reckoned to be an armoured fighting vehicle moving on caterpillar tracks. The Tsar tank, developed by Imperial Russia from 1914 onwards, instead used two huge front wheels in a tricycle configuration; the idea was that the enormous wheels could deal with any likely depth of trench. Most tanks like to keep as low a profile as possible, but this was a conspicuous exception. It would have been extremely visible on any battlefield.

The spoked wheels at the front were nearly 9 metres (30 ft) in diameter, but the third wheel at the back was only 1.5 metres (5 ft) in diameter.

Each front wheel was powered by a 250 HP Sunbeam engine. Sunbeam produced a wide variety of aero-engines, and is not currently known which design was used. The likeliest candidate is the Sunbeam Maori, a V-12 giving 250 HP from a 12-litre displacement.

Tests did not go well; the tank was underpowered and the rear wheel was prone to getting stuck in soft ground. The project was abandoned, and the tank was eventually scrapped in 1923.

The Tsar tank has rather brief Wikipedia page.

Apologies for the picture quality. No better pictures appear to exist. Note the two men on top of the tank body and one standing in the sponson, which has no gun mounted. The top turret has apertures for guns but none are mounted.

Left: The Tsar tank: 1915

This image (I am not sure if it is a model or a rendering) gives a much clearer view of the Tsar-tank's construction. There was a circular turret on top of the main body; it appears to have four guns at 90-degree spacing, so presumably did not traverse. The turret is too small to hold a decent-sized gun, and the field of fire is restricted as the turret is below the top of the front wheels.

There is also a turret with at least one gun underneath the main body, with an even more restricted field of fire, and two further guns mounted in sponsons on each side.

THE BOIRAULT BRIDGE TANK: 1914

Left: The Boirault Bridge tank Version-1: 1914

This prototype machine stretches the definitition of what is a tank; it is usually just called the Boirault machine. It had one huge track made from girders configured as six giant links that completely encircled the driving machinery inside it. The prototype had a top speed of only 1.9 mph. (3 kph) The arrangements for steering were basic indeed, consisting of a main jack that lifted the whole machine; then it could be turned up to 45° by hand effort from the outside or by a system of smaller jacks controlled from the inside of the machine. It was not a practical evolution under enemy fire.

The Boirault machine has a Wikipedia page.

There is some more info here.

Left: The Boirault Bridge tank Version-1: 1914

This gives a better idea of the construction and operation. The driving machinery was an 80 HP petrol engine mounted inside an A-frame construction.

Left: The Boirault Bridge tank Version-1: 1914

This shows the complicated system of chains that propelled the tank. There appear to be weights added at each side of the A-frame, presumably to increase stability.

There is more info and pictures of the Boirault Bridge tank here.

Left: The Boirault Bridge tank Version-2: 1916

A second version of the bridge-tank was built in 1916 that was lighter and more compact, with armour protecting the engine and the driving compartment. It had some degree of real steering control, but the minimum turning radius was an enormous 100 meters. The speed remained extremely low at 1 km/h. (0.6 mph)

Left: The Boirault Bridge tank Version-2: 1916

As for the first version, power transmission was by chains. The man on the left is believed to be M. Boirault.

After testing, the whole Boirault project was abandoned.

THE TREFFASWAGEN: 1917

Left: The German Treffaswagen tank: 1917

The Treffaswagen (which Google Translate unhelpfully renders as 'Treffa's car') was a tank project developed under contract by the Hansa-Lloyd works of Bremen, in parallel with the much better known A7V, which was the only German tank used in combat in WW1.

The prototype was finished on February 1, 1917. It had two 11 ft diameter steel wheels at the front, with a rectangular armoured body between them. The rear wheel was more of a big roller, and was used for steering; it had two smaller-diameter steel wheels on each side, whose porpose is currently unknown; possibly they were to resist the central roller getting bogged. It can just be seen at the right.

The body carried a forward-facing 2cm TUF gun, and on either side was a machine gun that fired through a central hole in the front wheel. They were intended for firing enfilade into trenches. This would have been potentially very destructive, but the Allies were quite aware of the need to build traverses into their trenches to prevent that sort of thing.

The prototype had a crew of four; commander, driver, gunner, and loader, and it weighed 18 tons. Only one prototype was constructed, and thoroughly tested during February and March 1917.

The results were disappointing; the centre of gravity was too far forward and if the front wheels dug into a ditch the tank could flip over onto its back. This actually happened once in the summer of 1917. The Treffaswagen was rejected in favour of the A7V. (Fun Fact: the approximately 50 captured British Mark IV tanks used by the Germans outnumbered the 20 A7V's they produced)

The Treffaswagen has a short Wikipedia page. (in Dutch)

Left: The German Treffaswagen tank: 1917

The Treffaswagen prototype seen from the rear, with a man to give the scale. Note the two smaller steel wheels on each side of the rear roller, purpose currently unknown.

Maximum speed was 10 km/h (6.2 mph)

THE ANSALDO MIAS/MORAS TANKETTE: 1935

Left: The Ansaldo MIAS/MORAS 35: 1935

The Motomitragliatrice blindata d’assaulto (MIAS) was a one man tracked vehicle built by the Ansaldo corporation in 1935.

It had a 250cc 5 HP engine which gave 5 km/hr forward speed and 2 km/h in reverse. Remarkably there was no seat for the one man crew, thus the crewman had to scuttle about in a crouch to follow the MIAS as it moved. The forward armour was designed to stop German 7.92x57mm Mauser rounds at the front, but the side armour would only stop Italian 6.5x52mm Carcano rounds. This was standard rifle ammunition; any sort of armour piercing ammunition would go straight through. The MIAS was armed with a 6.5mm machine gun with 1,000 rounds.

Ansaldo also built the Moto-mortaio blindato d’assaulto (MORAS), which was the same vehicle, but with the machine gun replaced with the odd 45mm Brixia mortar which used blank rifle cartridges to launch 500 gm high explosive mortar rounds. Fifty rounds were to be carried.

The Italian Army were keen on tankettes, such as the L3/35, which came utterly to grief every time it encountered Matilda: Queen of the Desert. Neither the MIAS or the MORA went into production, the Italian Army rightly declaring it useless for modern warfare.

There is an excellent page on the MIAS/MORAS at Tanks-encyclopedia.com.

THE RUSSIAN JUMPING TANK: 1937

A tank that can jump across rivers and other obstacles sounds like a ridiculous proposition. But the Soviet Russians tried it.

Left: The TPP-2 jumping tank: 1937

The following quoted text comes from "Report on the trials of the TPP-2 vehicle", confirmed by Barykov 1938, Leningrad, Kirov factory #185:

January
"The TPP-2 tank "Tank Preodoleniya Prepyadstviy" [Obstacle Crossing Tank] is designed to cross obstacles by jumping over them. A jump in this case is defined as the tank breaking contact with the ground and flying through the air freely."

"The TPP-2 is designed to use the kinetic energy of a moving tank. In order to test the principle of jumping using an artificial ramp, a tractor on the T-26 chassis was used. In order to increase speed, the tank's mass was reduced, and the tractor was without:
The upper armour plate (roof)
Various equipment, extra braces
The tank was only loaded with 1/3rd of its fuel capacity"

The idea is that the tank would build up speed, and rush at the obstacle. At the correct moment the four snail-shaped wheels (described in the report as "the eccentric gear") would be lowered so their smallest diameter engaged with the ground. As the tank's momentum carried it forward, the snail-wheels would rotate and lift it off the ground.

As you might imagine, testing did not go smoothly. While the tank could certainly be made to jump, it did not jump far and sustained considerable damage to its engine and transmission when it landed. The driver's seat was fitted with hydraulic shock-absorbers.

If you think the concept of tank-jumping died there and then, you would be wrong. It is done on a competitive basis at the Russian Army Games. The second video shows some tanks jumping, eg at 0:22 in.

THE SCHOFIELD TANK: 1940

The Schofield tank was developed in New Zealand when the Pacific war was getting closer and there seemed little prospect of getting fighting vehicles from Britain. It had both four wheels and tracks.

Left: The New Zealand Schofield tank in wheel mode: 1940

The changeover from wheels to tracks, and vice versa, could be accomplished from within the hull. The wheels and the track sprockets shared common axles.

There is a Wikipedia page.

Left: The New Zealand Schofield tank in track mode: 1940

The wheels were carried on the side of the tank when not in use. They look very vulnerable to combat damage.

Initial trials were not very successful; an improved version was ready by 1942 but by then tanks were arriving from Britain and the US. In 1943 the project was abandoned. The prototype was put into storage and then scrapped post-war.

Other fighting vehicles that are wheeled and tracked can be found on the 'N-wheel car' page:

THE KUGELPANZER BALL TANK: WW2

Left: The German kugelpanzer tank: WW2

This montrosity was produced during WW2 by Krupp. Kugelpanzer literally means ‘spherical tank’. Its purpose is still the subject of speculation; was it for reconnaissance, or wire-laying? It is usually called a tank, but with armour 5 mm thick at best, it would not do very well against real tanks.

There was a central cylindrical compartment with a single direct vision slit at head height, and below that is a welded-up hatch which could have been used by a machine-gun. There was an access hatch at the rear. The kugelpanzer was powered by a one-cylinder two-stroke engine, with which it could reach a slow 8 km/h. (5 mph) Steering and stabilisation was by a single wheel at the rear, which can just be seen in the picture at top right.

The only Kugelpanzer is in the Kubinka tank museum, having been captured by the Red Army; and apparently the Russians are very secretive about its materials of construction and the engine. It is very hard to see why- if it really had any military secrets it would never have been displayed in the first place.

There is more information at tanks-encyclopedia.com. The Kugelpanzer also has a Wikipedia page.

Left: The German kugelpanzer tank: WW2

This gives a good view of the little wheel at the rear. It does not look well-suited to crossing difficult ground.

The idea of a spherical tank goes back to at least 1936; see Popular Mechanix.

The Kubinka Museum also has the only Maus super-heavy tank prototype, and also the only four-tracked tank prototype; Object 279.

THE GERMAN WARGEL LW 3 TANK: 1942

Left: The German Wargel LW 3 tank: 1942

This picture greatly resembles the Treffaswagen above, but it is a later example of the big-wheel idea called the Wargel LW 3, built by Lauster GmbH in 1942.

The LW 3 was one of a series of Lauster designs running from LW 1 to LW 7. For example, the Lauster Wargel LW 5 had four big wheels and was constructed in 1943 to be a towing vehicle for a trench plough and as a heavy tank recovery vehicle. 'Wargel' is Swabian for a roller or drum.

There is more information here.

THE SWEDISH S-TANK: 1961

The opposite philosophy to that of the Tsar Tank was adopted by the Swedish Stridsvagn 103, better known as the S-Tank. This had some radical design features to give it a very low profile for a tank.

Left: the Swedish Stridsvagn 103 fixed-gun tank

The S-tank has no turret, giving it a very low profile. The Bofors 105mm L/62 gun is fixed to the chassis; elevation and depression are carried out by adjusting the hydropneumatic suspension. The gun is trained left and right by the tank turning, which it can do smoothly and precisely, even if there are obstacles around the tracks. It can swivel on its own axis.

It could be argued that the S-tank is more of a self-propelled gun, but its envisaged combat role was that of a tank. The first two production prototypes were completed in 1961, and full production began in 1965. The last S-tank was retired in 1997, being replaced by the Stridsvagn 122 tank, which is based on the German Leopard tank and has a conventional turret.

There is a good Wikipedia page on the Stridsvagn 103.

There is a great deal of information at tanks-encyclopedia.com.


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