Vickers Medium Dragon

Medium Dragon Mark I towing an 18-pounder (84 mm) field gun and ammunition limber

11 road wheels, six return rollers, side skirt running the length of the tracks like Johnson's 'Tropical Supply Tank'.

The nine crew members sat on three rather exposed forward-facing benches, plus a commander and driver in front.[8][9]

Two were converted by the Royal Ordnance Factory Woolwich for use by the RAF Armoured Car Company when the RAF took over responsibility and control of Mandatory Palestine, Trans-Jordan protectorate and parts of Iraq from 1922. The crew benches were removed, and an armoured body fitted with the turret from a Rolls-Royce armoured car. One was further transformed into a boxy armoured personnel carrier with rifle ports in the sides.[10]

Experiments were also made with the Mark I Dragon to use it as a Bridge carrier, with a 30 ft (9.1 m) footbridge. The two detachable steel beams which were carried on the side skirts of the Mark I may have been connected with this. By 1926 a Vickers Medium tank had also been adapted to be a bridgelayer, but with only a 16-foot (4.9 m) light girder bridge, it was found to be of no practical use.[11][12]

Medium Dragon Mark II*, three-quarter rear view

Distinguishing features include 11 road wheels (4 linked twin bogies, two separate wheels at the front, one at the rear), and five return rollers. The side skirt /mud chutes with 7 square holes, two vertical bars linking the side skirt to the main body. Headlights on stalks. Prominent upwards-facing triangular air intake in the centre of the front plate.

There was accommodation for eight men sitting sideways inside, plus two on rounded leather? seats at the rear aft of the ammunition boxes, plus a commander & driver at the front.[13]

A Pathé News film shows King George V at Aldershot in c1923 watching Army exercises, including his inspection of a Medium Dragon Mk II.[14]

The Medium Dragon Mark II* had some minor changes, including re-designed ammunition boxes.[15]

The Mark III appeared in around 1929.[16] The tracks had 11 road wheels (5 pairs flat on the ground and 1 single at the front), and six return rollers. The solid side skirt/mud chutes had four oblong holes. Five vertical bars linked the body to the side skirt. The headlights gained modern-looking faired housings. The air intake appears to be situated on the rh sloping front plate. Squared-off seats aft of the ammunition boxes at the rear of the body.[17]

The Mark IIIB had modified mud chutes/sideskirts with three large oval holes and two smaller vertical oval ones at each end.[16]

Data[16]

• Weight: about 9 tons
• Engine: air-cooled Armstrong-Siddley, same as in the Medium tanks.
• Speed: 16 mph (26 km/h)
• Capacity: 11 men
• Ammunition: 128 rounds of field gun ammo, stored in outwards-facing boxes with drop-down sides

The Mark IIIC had extra armouring apparently protecting the left-hand side crew. The headlight enclosures were squared-off, and the triangular engine cooling intake was turned downwards-facing on rh side front plate.

A 1942 US manual on the British Army shows a Medium Dragon Mark IIIC towing a 152 mm BL 6-inch 26 cwt howitzer.[18]

Medium Dragon Mark IV with 60-pounder (127 mm) gun

The Mark IV of c1932 was essentially a complete re-design, incorporating the running gear from the Vickers 6-ton Mark E: eight road wheels in two sets of paired bogies, quarter elliptical leaf spring suspension, and four return rollers. The side skirts on previous models were removed, leaving the running gear exposed. There was a distinctive shape to the tracks with the top run angled upwards towards the front.

Only twelve were sold to British Army in 1935, which adopted the official name of Dragon, Medium, Mark IV: some of these went to France with the BEF at the start of WWII.[19] The UK versions were fitted with an AEC 6-cylinder inline water-cooled diesel engine as fitted to London buses (eg the AEC Q-type). Export versions were powered by an Armstrong-Siddeley Puma 4-cylinder petrol engine developing 91.5 bhp (68.2 kW).

In 1935 the Army decided to concentrate on using wheeled vehicles for towing all the army's artillery (such as the Morris CDSW and later the Morris C8 "Quad", and the AEC Matador), and the procurement of tracked artillery tractors was dropped. Nevertheless, Mark IIIC Medium Dragons were still being used in 1942.[18]

Vickers exported considerably more Mark IVs (alongside 6-ton tanks) to foreign armies. 23 were sold to China in 1935 and India bought 18 tractors in 1937.[20] In 1932 one vehicle was sold to the German company Siemens-Schuckert; in 1933 Finland bought 20, and the same year 26 Mark IVs in an anti-aircraft version were sold to the Siamese (Thai) Army, armed with a QF 2-pounder (40 mm) "pom-pom".

According to David Fletcher, the running gear of the Matilda I infantry tank was derived from the Mark IV Dragon. During trials of early Matildas in 1936 the track pins failed constantly until relative height of drive sprocket and wheels were changed, and the rubber-tyred road rollers (which were subject to considerable wear) were replaced with steel ones.[21]

• Benson, C. C. (July 1929). "Mechanisation in Europe". The Coast Antiaircraft Journal. United States Coast Artillery Association. 71 (1).
• Chamberlain, Peter; Ellis, Chris (1973). Making Tracks: British Carrier Story 1914-1972. Profile Publications. ISBN 9780853830870.
• Fletcher, David (1994). Matilda Infantry Tank 1938–45. New Vanguard No. 8. Illustrated by Peter Sarson. Oxford: Osprey Publishing. ISBN 1855324571.
• French, David (June 2001). "Doctrine and Organization in the British Army, 1919-1932" (PDF). The Historical Journal. Cambridge University Press. 44 (2): 497–515. doi:10.1017/S0018246X01001868. JSTOR 3133617. S2CID 43202707.
• Suttie, William (2015). "British Tank Development following the First World War". The Tank Factory: British Military Vehicle Development and the Chobham Establishment. The History Press. ISBN 9780750963510.
• Ware, Pat (2011). British Tanks: The Second World War. Casemate Publishers. ISBN 9781783038374.