Design and development
Although there had been previous efforts to motorise heavy artillery transport during the First World War, such as the Holt tractor, the Gun Carrier Mark I and the Foster-Daimler Artillery Tractor to tow (in five loads) the BL 15-inch howitzer, the vast majority of British field artillery was still horse-drawn. [1]
Major-general Sir Louis Jackson, formerly Director of Trench Warfare at the War Office, suggested in a lecture he gave in December 1919 that the army should organize the entirety of its transport on the basis of trucks; the infantry, artillery, and engineers should be carried in tracked tractors and cross-country trucks capable of transporting them swiftly and safely across the battlefield. [2]
By late 1921 the War Office had begun the process of mechanising the Army's artillery. The United Service Gazette reported that "The War Office have given instructions for the four batteries of the 9th Brigade, Royal Field Artillery, now stationed at Deepcut, in the Aldershot Command, to be "mechanicalised" for the purpose of practical experiments. All the horses of the Brigade, except those of the officers, have been withdrawn and sent to the Remount Department. The personnel of the Brigade are now being trained to drive and to repair the kind of tractors to be used. It is understood that a tractor fitted with caterpillar tracks has been officially recommended for the trials, which are to take place shortly in the Aldershot Command. It is urged in favour of mechanical draught that it is economical in man power since the personnel of a battery might be reduced to approximately one half, when compared with one relying on horse draught." [3]
Lt-Colonel Philip Johnson of the Tank Design Department had been involved in tank development since 1918. Early designs after the war included the Medium Mark D, including variants such as an amphibious tank capable of 25 mph (40 km/h). [4] Another of Johnson's designs was a 'Light Infantry Tank', also based on the Medium Mark D. Johnson visited India in 1922 to see for himself the sort of requirements needed for a tank for the North-West Frontier. The trip resulted in a 7-ton 'Tropical Tank', together with a 'supply' (ie load-carrying) variant. [5]
The engine, an Armstrong Siddeley air-cooled petrol V-8 of 90 hp (67 kW) was installed at the front on the left, with radiator intakes/louvres in the front panel (which were reproduced in the Mark I Dragon). It had rear wheel drive, like the Medium Mark A Whippet and Vickers Medium Mark I and Vickers Medium Mark II tanks.
The 9th (IX) Brigade Royal Field Artillery took delivery of the supply variant in August 1922: subsequently two more prototypes were built, named the Vickers Dragon Nos. 1 & 2 Artillery Tractor (experimental). [4] [5] While the Light Infantry and Tropical Tanks used a novel tensioned wire rope suspension, the prototype Dragons had conventional coil suspension based on that of the Vickers Medium Mark I, with eleven small road wheels and six return rollers. This system was carried into production. [6]
Vickers began a limited production run in 1923, with the delivery of 18 Dragons Mark I, initially towing the Army's main field gun, the (84 mm) QF 18-pounder gun. [4] [5]
During 1923-4 the first two field artillery brigades were completely mechanized. At the same time the Royal Tank Corps, which had been placed on a permanent footing in September 1923, acquired its first Vickers Medium Tanks. [7]
