ABC Wasp

The ABC Wasp was an experimental 170 hp (127 kW) seven-cylinder radial engine designed by British engineer Granville Bradshaw, and primarily built by ABC Motors Limited. First run in 1916, twelve experimental ABC Wasp engines were delivered to Guy Motors on 19 April 1918. 56 were built in all.

The ABC Wasp was one of the first large stationary air-cooled radials. At a weight of 290 pounds (131 kg), it had a reasonable power-to-weight ratio at 0.6 horsepower per pound. This World War I–era engine is noteworthy because it was one of the first in which the cylinders were coated with copper in an attempt to dissipate heat. The ABC Wasp never evolved beyond the experimental stage, but it was the predecessor of the unsuccessful Dragonfly engine.

Variants:

Wasp I
1918, 160 hp (119 kW)

Wasp II
1919, 200 hp (149 kW), increased bore and stroke.

Applications:

Wasp I
Avro 504K
BAT Bantam
BAT Baboon
Sopwith Snail
Westland Wagtail

Wasp II
Avro 504K
BAT Bantam
Saunders Kittiwake
Sopwith Snail
Westland Wagtail

Specifications:

Wasp I
Type: 7-cylinder air-cooled radial
Bore: 4.53 in (115 mm)
Stroke: 5.9 in (150 mm)
Displacement: 667.1 cu in (10.78 L)
Diameter: 42 in (1,067 mm)
Dry weight: 290 lb (131 kg)
Fuel system: 2 Claudel-Hobson Carburettors
Fuel type: 40-50 octane petrol
Cooling system: Air-cooled
Power output: 185 hp (138 kW) at 1,750 rpm
Compression ratio: 4.05:1
Power-to-weight ratio: 0.63 hp/lb (1.05 kW/kg)