The Rolls-Royce Eagle Mk XXII [1] is a British 24-cylinder, sleeve valve, H-block aero engine of 46 litre (2,807 cubic inches) displacement.

The Rolls-Royce design team realised that producing a scaled-up version of their Griffon V-12 engine would lead to excessively large combustion chambers and problems with detonation.

This layout had previously caused unreliability with the Rolls-Royce Vulture due to the need to fasten four connecting rods in a complicated arrangement to a common big end bearing.

[2] The Eagle was never fitted to a production front-line fighter, as it was overshadowed by a new wave of turbojet engines, such as the Rolls-Royce Derwent and turboprops such as the Dart and Armstrong Siddeley Python.

Fifteen Eagle 22s were produced to power prototypes of the Westland Wyvern fighter/torpedo bomber because of delay in the development of the Python.