The de Havilland Gipsy Major is a 4-cylinder, air-cooled, inline engine that was used in a variety of light aircraft in the 1930s, including the famous Tiger Moth. The engine was a slightly modified Gipsy III that was effectively a de Havilland Gipsy engine modified to run inverted so that the cylinders pointed downwards below the crankcase. This allowed the propeller shaft to be kept in a high position without having the cylinders blocking the pilot's forward view over the nose of the aircraft. One disadvantage of the inverted configuration was the high oil consumption (up to 4 pints per hour) requiring regular refills of the oil tank. The cylinders on the Major were slightly bored out (118 mm from 114 mm) compared to the Gipsy III.
First built in 1932, UK production of all Gipsy Major versions was over 14,000 units; engines also being produced in Australia and New Zealand. The engine powered many light aircraft including de Havilland’s Puss Moth, Tiger Moth, Fox Moth, Dragonfly and Chipmunk, as well as many other designs from Auster and Miles. A development of this engine, the six-cylinder Gipsy Six produced 200 hp and powered small airliners such as the de Havilland Dragon Rapide, Dove and Heron.
The Tiger Moth on display at the Museum is powered by a de Havilland Gipsy Major engine.