| Foster-Daimler tractor | |
|---|---|
 | |
| Type | Tractor |
| Place of origin | United Kingdom |
| Service history | |
| Used by | United Kingdom |
| Wars | First World War |
| Production history | |
| Manufacturer | William Foster & Co. & Daimler Company Limited |
| Unit cost | £1,866 |
| No. built | 97 forRoyal Marine Artillery |
| Specifications | |
| Mass | Almost 14 long tons (14 t) |
| Engine | Daimler 6-cylinder double-sleeve valve petrol 105 bhp (78 kW) |
| Drive | 4x2 |
| Transmission | 2 speed |
| References | Vehicles at war[1] &The devil's chariots[2][page needed] |
TheFoster-Daimler tractor, often called theDaimler-Foster tractor, was a heavytractor built byWilliam Foster & Co. in the early 20th century. It was used by thearmed forces of the United Kingdom as a heavyartillery tractor during theFirst World War, it also formed the basis of the experimental Tritton trenching machine and its power unit was used in early Britishtanks.
The Foster-Daimler tractor weighed almost 14 long tons (14 t), it was powered by a Daimler 6-cylinder double-sleeve valvepetrol engine that developed 105 brake horsepower (78 kW) with a two-speed gearbox.[2][3] The tractors were driven bytraction engine-type rear wheels that were 8 feet (2.4 m) in diameter and 2 feet (0.61 m) wide; they could tow loads of 35 long tons (36 t).[2][page needed]
The Foster-Daimler tractor was first built in 1912 as a joint venture betweenLincoln based agricultural machinery manufacturersWilliam Foster & Co. andDaimler Company Limited. It was produced as a petrol-engined heavy tractor for export to countries with limitedcoal reserves, principally inSouth America.[1][2]
In late 1914 theCoventry Ordnance Works developed theBL 15-inch howitzer. Weighing over 60 long tons (61 t) these howitzers were broken down into several loads for road transportation.[2][page needed] Upon receipt of an order for twelve 15-inch howitzers from theRoyal Navy, the general manager of the Coventry Ordnance WorksRear-Admiral Reginald Bacon approached Daimler for the provision of tractors to tow the ordnance. Daimler referred Bacon toWilliam Tritton, the managing director of William Foster.[2][page needed] It was agreed the Foster-Daimler tractor would be adapted for the purpose of towing the broken down 15-inch howitzers, and an order for 97 tractors was placed at £1,866 per unit, along with 291 special towed wagons.[2][page needed]
Acceptance trials for the tractor were conducted in Lincoln on 10 December 1914, and in early 1915 the 15-inch howitzers and the Foster-Daimler tractors were taken into service with theRoyal Marine Artillery attached to theRoyal Naval Division.[1][2] In service, eight Foster-Daimler tractors were used to tow each 15-inch howitzer. The tractors could be used conventionally when travelling on roads or, if fitted with flanged wheels, could move alongrailways.[1]
The December 1914 acceptance trials included a bridging demonstration where a tractor towed two trailers of bridging timbers to a broad ditch; after engineers spanned the ditch, the tractor and trailers were waved across and one of the trailers toppled over the side, collapsing the bridge.[2][page needed] After this accident Bacon remarked to Tritton that an armed and armoured vehicle that could lay its own bridge would be of great value.[2][page needed] Bacon continued to press Tritton about the idea and designs were drawn up for a modified Foster-Daimler tractor capable crossing a gap. These were presented toWinston Churchill by the end of December and an order was placed for the production of an experimental prototype.[2][page needed]
The prototype, known by various names including the Tritton trenching machine, the Tritton trencher and the Tritton trench crossing machine, consisted of a Foster-Daimler tractor with the usual front wheels removed and a sub-frame fitted to the front of the chassis which had two wide road wheels in tandem – increasing the vehiclesoverall length to approximately 31 ft (9.4 m) – and two steel bridging girders 15 ft (4.6 m) in length were hung below the chassis on either side.[2][4][3] As the vehicle approached a trench the front wheel would protrude across, and as it made contact the girders were lowered allowing the machine to drive across the trench. Once across, the vehicle would winch the girders across, reverse over them and be prepared to cross another trench.[2][4][3] Bacon proposed fitting every trencher with a pair of headlights and another light on each side of the vehicles, each with glass 2 feet (0.61 m) in diameter and painted with the head of a ferocious Chinese warrior to unnerve the enemy during night attacks.[2][page needed]
Initially, the machine was to be ready for demonstration by 1 February 1915. This was subsequently delayed to mid-February but due to further various delays did not occur until 9 June 1915.[2][page needed] The machine had little difficulty in laying the girders over single trenches 8 ft (2.4 m) wide, but after crossing it required at least 25 ft (7.6 m) of clear ground to retrieve the girders. It was also found to be extremely nose-heavy, too cumbersome, and underpowered.[2][3] Despite the design's ingenuity, it was found to be impractical and the tractor was returned to its original configuration at a cost of £20.[2][3]
Probably the greatest contribution the Foster-Daimler tractor made to the war effort was to bring William Foster & Co, and particularly William Tritton, into the development and production of thetank.[1] Tritton was one of the engineers who developed the first completed tank design,Little Willie and its successor"Mother" ("Big Willie"), as well as theMark A "Whippet" andMark C "Hornet" medium tanks, with William Foster & Co. conducting much of the production.[1][5]
Little Willie, Mother, and the unchangedMark I tank used the Foster-Daimler tractor's 105 brakehorsepower Daimler engine,gear-box anddifferential, as it was one of the few power units available in England with the required power, speeding up development and production.[4][3][6] They were also used in the Mark II, Mark III, andMark IV tanks. Later, to increase the power of the engine, it was modified with aluminium pistons and dual carburettors to deliver 125 brake horsepower (93 kW), the upgraded engine being installed in the last 200 Mark IV tanks.[3][6]
