Dennis A Type

Dennis A Type
Type	3+1⁄2–4-ton lorry
Place of origin	United Kingdom
Service history
Used by	British Empire & United States
Wars	First World War
Production history
Manufacturer	Dennis Brothers
Produced	1913–1926
No. built	> 7,000[note 1]
Specifications (WD Pattern)
Mass	3.15 long tons (3.2 t) bare chassis
Length	20 ft 10 in (6.35 m) total 13 ft 2 in (4.01 m) wheelbase
Width	7 ft (2.13 m)
Engine	White and Poppe 6,232 cc (380.3 cu in) 4-cylinder petrol 49.6 bhp (37.0 kW)[note 2]
Payload capacity	3 long tons (3.05 t)[note 3]
Drive	4x2
Transmission	4-forward, 1-reverse
Suspension	Semi-elliptical leaf springs
Fuel capacity	30 imp gal (140 L; 36 US gal)
References	Pullen,[7] Vanderveen,[8] Commercial Vehicles of Great Britain Vol. 2,[10] Gosling[12] & Ware[13]

The Dennis A Type, often called the Dennis War Office Subsidy Type, was a British lorry built by the Dennis Brothers in the 1910s that saw widespread service with the militaries of the British Empire during the First World War. Upon the United States' entry into the war, a number were also supplied to the American Expeditionary Forces in France.

Design

The A Type was a cab behind engine, rear-wheel-drive truck with a payload capacity of 3+1⁄2–4 long tons (3.56–4.06 t), it had a chassis length of 13 ft 2 in (4.01 m)^{[note 4]} and a gauge of 5 ft 6 in (1.68 m), the bare chassis weighed 3.15 long tons (3.2 t).^[3][8][10] British Army's WD Pattern A Types were 20 ft 10 in (6.35 m) total length and 7 ft (2.13 m) wide.^[8]

Initially the A Type was powered by a 30 bhp (22 kW) Aster petrol engine, but was found to be underpowered so it was replaced by a 40 bhp (30 kW) 4-cylinder inline engine produced by White and Poppe.^[1][12] The early White and Poppe engine had a bore and stroke of 110 mm × 150 mm (4.3 in × 5.9 in) and a 5,701 cc (347.9 cu in) displacement, later the engine bore was increased to 115 mm (4.5 in) increasing the displacement to 6,232 cc (380.3 cu in) and the power to 49.6 hp (37.0 kW).^{[note 2][8][14]} The A Type was driven through a four-speed transmission, leaf spring suspension, hand actuated drum brakes on the rear wheels and a foot actuated transmission brake.^[10][12] The A Type's worm final drive rear axle was considered particularly advanced for the period.^[15] It had a removable upper casing which contained the worm shaft, worm wheel, differential and bearings, all of which could be inspected and replaced without disturbing the chassis or removing the wheels.^[15] It had steel wheels fitted with solid rubber tyres, twin wheels at the rear.^[10][12]

History

Convoy of A Type lorries of the Aviation Section, U.S. Signal Corps

A Type of the British Army with stores body

Originally bicycle makers, in 1898 the Dennis brothers began motorising tricycles, in 1901 they produced their first motor car, in 1903 or 1904 they produced their first commercial vehicle and in 1908 they produced their first fire engine.^[1][3] In 1913 Dennis was listed as a public company and suspended production of passenger cars, instead concentrating on production of commercial vehicles including busses, fire engines and lorries.^[1][4]

That year Dennis introduced the A Type, first exhibiting it at the Commercial Vehicle Show at the Olympia Exhibition Centre.^[2][3] The A Type was designed by Dennis to comply with the War Office motor vehicle "subsidy scheme" requirements.^{[note 5][2]} In 1913 when the A Type was presented at a War Office trial for certification under the scheme,^{[note 6]} it failed, its original 30 bhp (22 kW) Aster engine being considered underpowered.^[12] Having re-engined the lorry with the more powerful White and Poppe engine, at the subsidy scheme trials held in early 1914 Dennis received certification for the A Type.^[12] The A Type was the last lorry to be certified before war was declared.^[12]

During the First World War, Dennis produced only two vehicle models, the A Type and the N Type fire engine.^[9] In 1915 the War Office took over direct control of Dennis for the duration of the War,^[18] and by the end of the conflict over 7,000 had been delivered.^{[note 1][1][2][3]} In military service, the Dennis A Type was found to have among the best performance of the British Subsidy Type lorries.^[2] Rated for payloads of 3 long tons (3.05 t),^{[note 3]} when fully loaded the A Type could climb gradients as steep as 1 in 6.^[2]

Upon their arrival in Europe in 1917, the British supplied the American Expeditionary Forces with a number of A Types.^[19] It is unknown how many A Types were supplied to the Americans, but it was likely hundreds.^[19]

Post-War, the British War Office auctioned off thousands of surplus military vehicles to the British public.^[20] Demobilised A Types proved popular with civilian operators.^[21] The A Type had considerable influence on post-War British lorry designs, and despite introducing new models, Dennis continued production of the A Type until 1926.^[4][15]

Dennis-Stevens

Towards the end of the War, William Stevens of Tilling-Stevens parted company with Thomas Tilling, and joined Dennis.^[22] Stevens successfully mated his petrol-electric designs to the A Type, creating the Dennis-Stevens lorry.^[22] The War Office mounted large searchlights on the Dennis-Stevens, using the engine-driven generator to power the lamp.^[23] By the end of the War in 1918, 187 Dennis-Stevens searchlight carriers had been delivered to the War Office, 74 of which had been sent to France.^[23] After the War the Dennis-Stevens remained in production for some time as an easy to drive bus chassis.^[4]

Notes

References

External links

Media related to Dennis A Type at Wikimedia Commons.