page_title: Vickers 6-Ton
section_title: History
hierarchical_section_title: Vickers 6-Ton / History
caption_attribution_description: Marian Machocki, in the turret of his Vickers Mark E Type B light tank.
context_page_description: The Vickers 6-Ton Tank or Vickers Mark E was a British light tank designed as a private project at Vickers. It was not purchased by the British Army, but was picked up by many foreign armed forces. It was licensed by the Soviets as the T-26. It was also the direct predecessor of the Polish 7TP tank.
context_section_description: The first Mark E was built in 1928 by a design team that included the famed tank designers John Valentine Carden and Vivian Loyd. The hull was made of riveted steel plates, 1 inch (25.4 mm) thick at the front and over most of the turrets, and about ³⁄₄ inch (19 mm) thick on the rear of the hull. The power was provided by an Armstrong Siddeley Puma engine of 80–95 horsepower (60–71 kW) (depending on the version), which gave it a top speed of 22 mph (35 km/h) on roads.
  The suspension used two axles, each of which carried a two-wheel bogie to which a second set of bogies was connected with a leaf spring. Upward movement of either set of bogies would force the other down through the spring. This was considered to be a fairly good system and offered better than normal cross-country performance although it could not compare with the contemporary Christie suspension. High strength steel tracks gave over 3,000 miles (4,800 km) of life which was considerably better than most designs of the era.
  The tank was built in two versions:
  Type A with two turrets, each mounting a Vickers machine gun.
  Type B with a single two-man turret mounting a single machine gun and a short-barreled 47 mm OQF 3-pdr Gun.
  The Type B proved to be a real innovation: it was found that the two-man turret dramatically increased the rate of fire of either weapon, while still allowing both to be fired at the same time. This design, which they referred to as a duplex mounting, became common on almost all tanks designed after the Mark E.
  The British Army evaluated the Mark E, but rejected it, apparently due to questions about the reliability of the suspension. Vickers then started advertising the design to all buyers, and soon received a trickle of orders eventually including USSR, Greece, Poland, Bolivia, Siam, Finland, Portugal, China and Bulgaria. Thailand purchased 36 Vickers Medium Dragon Mark IV, and QF 2-pounder naval guns were added to turn them into self-propelled guns used in the Franco-Thai War. Vickers built a total of 153 (the most common figure) Mark Es.
  Experience with the Polish machines showed that the engine tended to overheat due to poor airflow over the air-cooled Puma engine. This was addressed by the addition of large air vents on either side of the hull. For a new Belgian order the design was modified to use the Rolls-Royce Phantom II water-cooled engine instead. This engine would not fit in the rear, and had to be mounted along the left side of the tank, requiring the turret to be moved to the right and rearward. One example of the resulting Mark F was tested by Belgium, but rejected. Nevertheless, the new hull was used, with the older engine, in the sales to Finland and Siam.
  The Mark E was also developed as a cargo vehicle, and purchased by the British Army in small numbers as artillery tractors to haul their large BL 60-pounder (127 mm, 5 in) field guns. Twelve were ordered by the Army as the Dragon, Medium Mark IV, while China purchased 23 and India 18.
  Poland purchased 50, and also licensed it for the local production, but only put together 38 out of the 50, using the unassembled 12 for spare parts. The Poles modified their vehicles with larger air intakes, their own machine gun, a 360-degree Gundlach periscope, and 5 or more with added two-way radios, before deciding to make their own tank that would address the shortcomings of the original Vickers design. This resulted in the 7TP, which was nearly 10 tons in weight. The Poles also, besides the aforementioned telescope, added a liquid-cooled Diesel engine as well as better armor protection, better ventilation, two-way radios, a 37 mm (1.46 in) Polish version of Bofors anti-tank gun, and a bigger crew compartment. Out of 38 original two-turreted tanks, 22 were later converted to single turret version with a modified turret and the 47 mm (1.85 in) main gun (Type B standard). The tanks were in bad shape by 1939 because they were used in the training units over a period of five years. However, they did perform well and better than the Renault R35, amongst others as part of the Polish 10. 
caption: Polish Vickers E in 1938
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