Foster-Daimler Gun-tractor

In the early 1900's, Sir William Tritton was the inventive Managing Director of Foster & Co, Lincoln. As such, he attended the 1909 military tractor trials. The result of which was the Foster-Daimler tractor, first produced in 1912.foster-daimler

The winner of the 750 first prize for tractors in the 1909 trial was the Thornycroft. Tritton had been impressed with the Thornycroft's performance and determined to combine Foster's existing steam expertise with an internal combustion engine.

Convinced that a heavy tractor would benefit from more power than the 50hp provided by Thornycroft, Tritton turned to Daimler in Coventry. Daimler had a 6-cylinder, sleeve-valve, 105hp petrol engine of 14.6 litres and this was the engine that Tritton used for the tractor. The same engine was later used in the first tanks.

The tractor followed traction engine principles with a sturdy channel plate chassis and large, 8ft diameter sprung traction engine rear wheels. The end result was a similar vehicle to the 1909 Thornycroft, though more powerful and larger. A two-speed gearbox provided 2.5mph and 5mph in forward gears with 2.5mph possible in reverse.

Weighing 11.5 tons, it proved too large for domestic use, and few were built prior to 1914. When tested by the War Office at Boulogne in February 1915, it proved capable of towing 35 tons at 2mph while using 1.5 gallons of petrol every 2 miles.

The Coventry Ordnance Works had long supplied the Admiralty with 15-inch naval guns. When WW1 was declared the head of the company, Admiral Sir Reginald Bacon, approached Winston Churchill who was First Lord of the Admiralty, with the idea of 15-inch howitzers. These were to be used for heavy bombardment in France and this approach resulted in an initial order for 10 guns and presented the immediate problem of transportation.

foster-daimlerThe howitzers were extremely heavy and though they could be broken down into component parts for transportation, still presented a major challenge. Bacon decided on the Foster-Daimler as the most suitable gun-tractor. With the ammunition trailers included, a total of 8 tractors were required for each gun. The guns were broken down into barrel, cradle and carriage for transportation and reassembled when in position.

Responsibility for manning and transporting these huge guns was that of The Royal Marines Artillery, using Army Service Corps drivers. Repair and maintenance was carried out at the 3rd Heavy Repair Shop (358 Coy ASC) at St Omer in Northern France. Spares and stores supplies were provided through No2 Base MT Depot at Calais, just a few miles north of St Omer.

In all, the Admiralty ordered 97 tractors and 291 specially built trailers for transporting the guns in component form. The broken down guns needing three trailers each.

An important aspect of the design of the Foster-Daimler was its ability to be converted for use on railway lines by simply changing the traction engine wheels for flanged wheels.

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