Armstrong Siddeley Hyena

1930s British piston aircraft engine

Hyena
Type	Radial engine
Manufacturer	Armstrong Siddeley
First run	1933
Major applications	Armstrong Whitworth A.W.16

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.

Hyena: 15 cylinders (5 banks of 3 cyl.)
Terrier: 14 cylinders (7 banks of 2 cyl.)
Deerhound: 21 cylinders (7 banks of 3 cyl.)
Wolfhound: 28 cylinders (7 banks of 4 cyl.)
Boarhound: 24 cylinders (6 banks of 4 cyl.)
Mastiff: 36 cylinders (9 banks of 4 cyl.)

Specifications (Hyena)

Data from Lumsden.^[3]

General characteristics

Type: 15-cylinder 3-row radial engine with inline banks.^[1]
Bore: 5.3 in (137 mm)
Stroke: 4.88 in (125 mm)
Displacement: 1,615.58 cu in (26.6 L)

Components

Valvetrain: Overhead poppet valves
Supercharger: Medium supercharged
Fuel type: 77 Octane petrol
Cooling system: Air-cooled
Reduction gear: Epicyclic geared, left hand tractor

Performance

Power output: 618 hp at 2,000 rpm at sea level

References

Notes

^ ^a ^b Gunston, Bill (1986). World Encyclopedia of Aero Engines. Guild Publishing. p. 18. 3-row radials
^ Pearce, William. "Armstrong Siddeley 'Dog' Aircraft Engines". oldmachinepress.com. Retrieved 9 May 2016.
^ ^a ^b Lumsden 2003, p.76.