The Armstrong Siddeley Cheetah is a seven-cylinder British air-cooled aircraft
radial engine of 834 cu in (13.65 L)
capacity introduced in 1935 and produced until 1948. Early variants of the Cheetah were initially known as the Lynx Major.[1]
The Cheetah was developed from the earlier Lynx using the increased
bore cylinders from the
Armstrong Siddeley Panther but the engine retained the
stroke of the Lynx. Initially only direct-drive variants were produced with later engines being made available with propeller reduction gear of various
ratios.
Superchargers were also available for later variants, both geared and directly driven by the
crankshaft.[1]
The basic design of the Cheetah remained unchanged from its introduction in 1935 to the last examples built in 1948. It was the first engine of its type to be certified for 1,200 hours of operational
time between overhauls (TBO), with over 37,200 examples built.[2]
As of October 2008 at least four Cheetah engines remained airworthy. Two Cheetah 17s power the
Anson T21 operated by the
Classic Air Force and another pair of Cheetah 17s are fitted to Avro Nineteen, G-AHKX registered to
BAE Systems but normally based at the
Shuttleworth Collection.[6][7]
Engines on display
Preserved Armstrong Siddeley Cheetah engines are on public display at the following museums: