The Armstrong Siddeley Hyena was a British aero engine developed by Armstrong Siddeley. Designed in the 1930s, it was an unusual experimental radial engine with inline cylinder banks.[1] It was flown using an Armstrong Whitworth A.W.16 fighter aircraft as a test bed. Unresolved problems with cooling of the rear cylinders prevented the engine from going into production.[2] Few details of this engine survive as company records were lost.[3]
Armstrong Siddeley in-line radial engines
The Hyena arrangement of cylinder banks arranged as a radial engine was continued with further designs, but with little commercial success, with only the Deerhound and Hyena being built.