de Havilland Gyron Junior

The de Havilland Gyron Junior was a military turbojet engine design of the 1950s developed by the de Havilland Engine Company and later produced by Bristol Siddeley. The Gyron Junior was a scaled-down derivative of the de Havilland Gyron. Only a little more widely used than the Gyron, it did at least enter serial production for the Blackburn Buccaneer S.1 twin-engined Naval strike aircraft. However it was never a successful engine in service. The Buccaneer S.1 was criticised for being underpowered and the later and more numerous S.2 used the more powerful Rolls-Royce Spey instead.

General characteristics

  • Type: Single-spool after-burning turbojet
  • Length: 102.9 in (2.61 m)
  • Diameter: 41.1 in (1.04 m)
  • Dry weight: 1940 lb


  • Maximum thrust: 7,350lbf (44.48kN) dry, with 14.2 lb air bleed 7,100 lbf)
  • Overall pressure ratio: (DGJ.1)6.4:1
  • Turbine inlet temperature: (DGJ.1)1,200 C (2,190F)
  • Power-to-weight ratio: 3.8:1 lbf


  • Compressor: 7-stage axial flow with Variable Inlet GuideVanes (VIGV)
  • Combustors: Annular combustion chamber with 13 spill-type burners
  • Turbine: Two-stage axial flow
  • Fuel type: Aviation kerosene
  • Oil system: Self contained dry sump system