Armstrong Siddeley Hyena
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. First run in 1933, 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. Few details of this engine survive as company records were lost.
Type: 15-cylinder 3-row radial engine with inline banks.
Bore: 5.3 in (137 mm)
Stroke: 4.88 in (125 mm)
Displacement: 1,615.58 cu in (26.6 L)
Valvetrain: Overhead poppet valves
Supercharger: Medium supercharged
Fuel type: 77 Octane petrol
Cooling system: Air-cooled
Reduction gear: Epicyclic geared, left hand tractor
Power output: 618 hp at 2,000 rpm at sea level