Rolls-Royce Clyde

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RB.39 Clyde
Type Turboprop
Manufacturer Rolls-Royce Limited
First run 5 August 1945[1]
Number built 9[2]

The Rolls-Royce RB.39 Clyde was Rolls-Royce's first purpose-designed turboprop engine and the first turboprop engine to pass its civil and military type-tests.[2][3]

As with subsequent Rolls-Royce gas turbines, it was named after a river, the River Clyde.

Design and development[edit]

The Clyde used a two-spool design, with an axial compressor based on that of the Metrovick F.2[4][5] for the low-pressure section, and a single-sided centrifugal compressor scaled up from the Merlin 46 supercharger [6] as the high-pressure stage, running on concentric shafts.[1] The first versions produced 4,030 eshp and were selected as the main engine of the Westland Wyvern TF Mk.2 strike aircraft.[2]

The Clyde was a long engine with the axial LP compressor in front of what was, in effect, a scaled-down Derwent engine. Accessories were grouped around the axial compressor which conveniently narrowed towards the rear. Cooling for turbines and turbine bearings came from a small diffuser on the main shaft as well as tappings from the axial and centrifugal compressors. Testing of the development engines exceeded expectations with the engine soon being rated at 4,030 eshp. One problem un-earthed during testing was that damaging resonances emanated from the straight-cut spur gears in the reduction gearbox.[1]

Despite the promising performance of the test engines Ernest Hives felt that pure-jets such as the Avon were the future and the Clyde programme was terminated, forcing Westlands to use the less than satisfactory Armstrong Siddeley Python on the production Wyverns.[2] and Rolls-Royce's first production turboprop would be the Dart.

Specifications (Clyde)[edit]

Data from Turbojet History and Development 1930-1960 vol.1[1]

General characteristics

  • Type: Twin-spool turboprop
  • Length: 10.1 ft (3.08 m)
  • Diameter: 3.9 ft (1.19 m)
  • Dry weight: 2,800 lb (1,300 kg)


  • Compressor: LP - 9 stage axial, HP - Single centrifugal stage
  • Combustors: Eleven can-type combustion chambers
  • Turbine: HP - single stage axial, LP - single stage axial
  • Fuel type: Kerosene (jet fuel grade)
  • Oil system: Pressure spray scavenge system


Engines on Display[edit]

A part sectioned example is on display at the Rolls-Royce Heritage Trust Collection (Derby)

See also[edit]

Related lists



  1. ^ a b c d Kay, Anthony L. (2007). "14". Turbojet History and Development 1930-1960 vol.1 (1st ed.). Marlborough: The Crowood Press. pp. 105–118. ISBN 978-1-86126-912-6.
  2. ^ a b c d Gunston, Bill (2006). World Encyclopedia of Aero Engines (5th ed.). Stroud: Sutton Publishing. pp. 194–195. ISBN 0-7509-4479-X.
  3. ^ Flight 1954, p. 582.
  4. ^ McKenzie, A. (2001). Axial Compressor Development at Rolls-Royce Derby, 1946–1962. Rolls-Royce Heritage Trust. pp. 10, 23. ISBN 978-1-872922-42-3. Technical Series Nº11.
  5. ^ "World Encyclopedia of Aero Engines – 5th edition" by Bill Gunston, Sutton Publishing, 2006, P.195
  6. ^ "World Encyclopedia of Aero Engines – 5th edition" by Bill Gunston, Sutton Publishing, 2006, P.195