Bristol Proteus

The Bristol Proteus was the Bristol Aeroplane Company's first successful gas-turbine engine design, a turboprop that delivered just over 4,000 hp (3,000 kW). The Proteus was a two spool, reverse-flow gas turbine, similar to the original Whittle engine designs with an extra turbine stage. Because the turbine stages of the inner spool drove no compressor stages, but only the propeller, this engine is sometimes classified as a free turbine. It was used mostly on the Bristol Britannia airliner, but saw some third party use as well.

General characteristics

  • Type: Turboprop
  • Length: 97.6 in (2,480 mm)
  • Diameter: 37.9 in (960 mm)
  • Dry weight: 1,207 lb (547 kg) (dry)


  • Maximum power output: 3,320 shp (2,475 kW) + 1,200 lb (5.33 kN) residual thrust giving 3,780 eshp
  • Overall pressure ratio: 7.2:1
  • Fuel consumption: 273 Imp gal (1,241 L) /hour
  • Specific fuel consumption: 0.495 lb/h/eshp


  • Compressor: Two-spool 12-stage axial, followed by a single centrifugal stage
  • Combustors: Reverse-flow
  • Turbine: Two-stage power (free turbine), two-stage driving compressor
  • Fuel type: Aviation kerosene