De Havilland Gipsy

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.

The Gipsy went on to become one of the most popular sport aircraft engines of the inter-war period and was the engine of choice for various other light aircraft, trainers, liaison aircraft and air taxis, British as well as foreign, until long past WWII. Apart from helping to establish the de Havilland Aircraft Company as a manufacturer of light aircraft, it also established the company as an engine manufacturer in its own right.

Gipsy engines remain in service powering vintage light aircraft.