de Havilland Gipsy is a British air-cooled 4-cylinder in-line aircraft engine designed by Frank Halford in 1927 to replace the ADC Cirrus in the de Havilland D.H.60 Moth light biplane.
The new Gipsy was an air-cooled 4-cylinder in-line engine weighing a mere 300 pounds and rated at 98hp (73kW) at 2,100 rpm. The cylinders had a bore of 4.5in and a stroke of 5in (114mm × 128mm) for a displacement of 319cu.in (5.23l).
It was soon developed further into the 120hp (90kW) Gipsy II. Both types were to be used in the new version of the de Havilland Moth: the D.H.60G Gipsy Moth. The new engine proved itself to be docile, easy to maintain and, as demonstrated in many long distance flights by the new Gipsy Moth, reliable.
The Gipsy went on to become one of the most famous 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.
Rare footage of a Gypsy Moth aircraft with Gypsy 1 engine