query: subclass_of napier rapier
supports: The de Havilland Gipsy is a British air-cooled four-cylinder in-line aircraft engine designed by Frank Halford in 1927 to replace the ADC Cirrus in the de Havilland DH.60 Moth light biplane. Initially developed as an upright 5 litre (300 cubic inch) capacity engine, later versions were designed to run inverted with increased capacity and power. An aircraft engine is the component of the propulsion system for an aircraft that generates mechanical power. Aircraft engines are almost always either lightweight piston engines or gas turbines, except for small multicopter UAVs which are almost always electric aircraft. The Napier Rapier was a British 16 - cylinder H pattern air - cooled aero engine designed by Frank Halford and built by Napier & Son shortly before WWII . De Havilland Aircraft Company Limited was a British aviation manufacturer established in late 1920 by Geoffrey de Havilland at Stag Lane Aerodrome Edgware on the outskirts of north London. Operations were later moved to Hatfield in Hertfordshire. Major Frank Bernard Halford CBE FRAeS (7 March 1894  16 April 1955) was an English aircraft engine designer. He is best known for the series of de Havilland Gipsy engines, widely used by light aircraft in the 1920s and 30's.
candidates: aircraft aircraft engine aviation de havilland gipsy electric aircraft engine lane light line march moth propulsion series
answer: aircraft engine