AEC Y Type
AEC Y Type, 1917
Type	3-ton lorry
Place of origin	United Kingdom
Service history
Used by	United Kingdom United States
Wars	First World War
Production history
Designer	Associated Equipment Company
Manufacturer	Associated Equipment Company
Produced	1915–1922
No. built	≈10,000
Variants	Y Type, YA, YB & YC
Specifications
Mass	4.21 long tons (4.28 t)
Length	23 ft 6 in (7.16 m) 14 ft 3 in (4.34 m) wheelbase
Width	6 ft 11 in (2.11 m)
Height	10 ft 2 in (3.10 m)
Engine	Y Type: Daimler inline 4-cylinder 5.7 L petrol 40 bhp (30 kW) at 1,300 rpm YA, YB & YC: Tylor 4-cylinder 7.7 L petrol 49 bhp (37 kW) at 1,300 rpm
Payload capacity	3 long tons (3.0 t)
Drive	4x2
Transmission	4 Forward, 1 reverse gear
Suspension	Semi-elliptical multi-leaf springs
Maximum speed	12 mph (19 km/h)
References	A complete directory of military vehicles[1]

The AEC Y Type was a British truck built by the Associated Equipment Company (AEC), it saw widespread service with the British Army during the First World War.

The original Y Type was a 3-ton 4x2 truck powered by a Daimler four-cylinder inline 5,700 cc petrol engine that developed 40 brake horsepower (30 kW) at 1,300 rpm, it drove the rear wheels through a four-speed gearbox, the wheels having solid rubber tyres.^[1][2] The Y Type had an open, canvas covered cab and a fixed side timber body, typical of military cargo vehicles of the period.^[1]

The YA, introduced in 1917, replaced the Daimler engine with a Tylor four-cylinder inline 7,700 cc petrol engine that developed 49 brake horsepower (37 kW) at 1,300 rpm, the YB introduced a pressed steel frame whilst the YC used a David Brown Ltd. worm-gear final drive.^[1][2]

The Y Type was introduced by AEC in March 1915, it was a lower geared development of AEC's earlier X Type, the latter in turn a development of the company's W Type with heavier duty hubs.^[1] Whilst AEC was founded in 1912, a sales agreement meant that all of its products were marketed by and branded Daimler, in June 1916 the company's factory, at Walthamstow, was placed under direct government control and the lorries were branded AEC from that date, although the Y Type's distinctive Daimler radiator was retained.^[1]

The Y Type was in high demand by British forces during the First World War, in 1917 AEC installed a moving assembly line to make the type, enabling the factory to produce 130 chassis per week.^[1][2] In addition to British forces the type was also used by the United States Army in France.^[1] By the Armistice in November 1918, AEC had built 8,821 Y Types, 5200 of which were fitted with the Tylor engine.^[1]

The War Office purchased an additional 822 Y Types in 1919 and the type remained in production for civilian customers until 1922.^[1] as a 5-ton lorry^[3] A number of Y Types were sold to civilian operators after the war, a common conversion saw the military body removed and the chassis used as the basis of an omnibus.^[1]