ABC Scorpion

The ABC Scorpion is a 30 hp (22 kW) flat twin, two-cylinder aero engine designed by British engineer Granville Bradshaw for use in light aircraft. The engine was built by ABC Motors Limited and first ran in 1921.

Variants:

Scorpion I
1923, 30 hp (22 kW)

Scorpion II
1924, 34 hp (25 kW), increased bore and stroke.

Applications:
ABC Robin
Boulton Paul Phoenix
BFW M.19
BFW M.23
Comper Swift
de Havilland Humming Bird
Farman Moustique
Hawker Cygnet
Heath Parasol
Hendy Hobo
Henderson-Glenny Gadfly
Kay Gyroplane
Luton Minor
Mignet HM.14 Pou-du-Ciel
Parmentier Wee Mite
SAI KZ I
Short Satellite
Snyder Buzzard
Wheeler Slymph
Westland Woodpigeon

Specifications:

Scorpion I
Type: 2 cylinder air cooled flat-twin
Bore: 3.6 in (87.5 mm)
Stroke: 3.7 in (91.5 mm)
Displacement: 73.32 cu in (1.1 L)
Dry weight: 90 lb (41 kg)
Valvetrain: Overhead valve, two valves per cylinder
Fuel system: Carburettor
Fuel type: 74 Octane petrol
Cooling system: Air
Power output: 30 hp (22 kW) at 2,750 rpm
Compression ratio: 4:1
Power-to-weight ratio: 0.33 hp/lb (0.53 kW/kg)