Object StatementAircraft engine, ABC Wasp No.1 experimental radial aero engine, 26N, No.44789, air cooled, 7 cylinders, 170 hp, 1900 rpm, steel and aluminium, developed during World War I, designed by Granville Bradshaw, made by Crossley Motors Ltd, Manchester, England, 1918
Physical DescriptionAircraft engine, ABC Wasp No.1 experimental radial aero engine, 26N, No.44789, air cooled, 7 cylinders, 170 hp, 1900 rpm, steel and aluminium, developed during World War I, designed by Granville Bradshaw, made by Crossley Motors Ltd, Manchester, England, 1918
The ABC Wasp aircraft engine comprises a seven cylinder, single row, air-cooled radial engine designed to provide 170 hp at 1900 rpm. The cylinder assemblage was fixed relative to the aircraft fuselage while the propeller rotated with the crankshaft. The appearance of the engine is not significantly different from a rotary engine. Cam-driven push rods protrude from the crankcase in the front of the engine and actuate the inlet and exhaust valves in the cylinder head through rocker levers. Each cylinder has one large inlet valve and two smaller exhaust valves. The spring loaded inlet valve rod passed through the mixture transfer pipes at the rear of the engine. The rocker arm for the exhaust valves acted on a cross piece which connected with the valve rods to either side of each cylinder head. Exhaust pipes, which are joined to the ports, conveyed the products of combustion through the engine cowling.
The cylinders are steel forgings with integral heads while the cooling fins are coated with copper in an attempt to improve cooling. The pistons are of aluminium alloy. Two Claudel-Hobson H.C.8 carburettors and two magnetos are fitted.
In all radial engines, one of the connecting rods connected with the crankshaft in a conventional manner. This connecting rod was designated as the 'master rod' and the other connecting rods articulated with the master rod.
The engine operated on the four-stroke cycle where the air was first drawn through a carburettor then through the hollow crankshaft to an annular chamber behind the crankcase and finally to the engine cylinders. A magneto fired the spark plugs mounted on the side of each cylinder. Ignition occurred in alternate cylinders, in the sequence 1, 3, 5, 7, 2, 4, 6, during each engine revolution.
Height: 1050 mm
Length: 1000 mm
Depth: 750 mm
Cylinder diameter: 115 mm
Piston stroke: 150 mm
Weight: 290 lbs (131.5kg)
Compression ratio: 4.05:1
MarksABC ENGINE TYPE WASP No1
FIRING ORDER 1,3,5,7,2,4,6
MANUFACTURED BY CROSSLEY MOTORS Ltd
'AID' 26N and 'A 44789'