Hewland AE75

The Hewland AE75 is a lightweight aircraft engine that was manufactured in the mid-1980s by Hewland in Maidenhead, United Kingdom. The engine, a two-stroke inverted inline triple of 750 cc (46 cu in) displacement, is liquid-cooled and yields 75 hp (56 kW)

Design and development

Th AE75 was developed from Hewland’s own 500 cc (31 cu in) twin-cylinder microlight engine. The engine was designed specifically for the ARV Super2, a lightweight two-seater shoulder wing aircraft. The AE75's design is compact and light at 49 kg (108 lb) and yields a power-to-weight ratio of 1.14 kW/kg. Lubrication is via 40:1 pre-mix two-stroke oil.

Each of the engine’s three cylinders has its own carburetor, with an alternate air device to provide carburetor heat. Each cylinder has twin spark plugs, the sparks being provided by a dual ignition system using engine-triggered amplifiers and coils, rather than the more common aviation magneto. The ignition circuit redundancy is such that if one circuit should fail, all three cylinders will still run. Even if two circuits fail, the engine will still fire on two out of three cylinders.