Best known for their range of high quality motor cars, Alvis Limited in Coventry began work on aero engines in 1935 developing the Pelides and Leonides radial engines. The nine-cylinder, single-row Leonides was first run in December 1936 and was subsequently tested by Airspeed Ltd in their Bristol Bulldog. Development work was delayed by World War II as these engines were intended for civil use. The Series 500 Leonides was manufactured from 1947 and was fitted to aircraft including the Percival Prince, the Scottish Aviation Twin Pioneer and the Bristol Sycamore helicopter. Production ceased in 1966.

This 500 Series Leonides engine was donated to the Museum in 1973 by the Royal Melbourne Institute of Technology.

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