Volvo RM8

The Volvo RM8 is a low-bypass afterburning turbofan jet engine developed for the Saab 37 Viggen fighter. In 1962, the Pratt & Whitney JT8D-1 engine was chosen to power the Viggen in absence of a suitable and available engine designed for military use. Basically a licensed-built version of the JT8D, heavily modified for supersonic speeds, with a Swedish-designed afterburner, the RM8 was produced by Svenska Flygmotor (later known as Volvo Aero).[1]

RM8
An RM8 on display at the Swedish Air Force Museum
Type Turbofan
National origin United States/Sweden
Manufacturer Volvo Flygmotor/Pratt & Whitney
First run 1964
Major applications Saab 37 Viggen
Developed from Pratt & Whitney JT8D
An RM8 on display at the Swedish Air Force Museum

Variants and applications

Since the original engine was constructed for subsonic speeds, most parts of the engine had to be redimensioned for the higher Mach-speeds in a military aircraft. Fans and turbine were altered, a new combustion-chamber designed and a totally new fuel-control system for both engine and afterburner.[2]

The flight envelope for the fighter-version demanded both more power and better compressor stall margins. This led to a new fan-stage (the so-called "0-stage") was introduced, making the engine longer. This led to a total redesign of the fans, the low-pressure compressor and the combustion-chambers.[3]

Specifications (RM8B)

Data from Flight International.[4]

General characteristics

  • Type: Afterburning turbofan
  • Length: 6.23 m (20.44 ft)
  • Diameter: 1.03 m (40.55 in)
  • Dry weight: 2,350 kg (5,180 lb)

Components

  • Compressor: Axial flow, 3-stage fan, 3-stage LP, 7-stage HP
  • Combustors: 9 chambers in can-annular arrangement, four injectors per chamber

Performance

See also

Related development

Related lists

References
Notes
  1. Gunston, p. 236
  2. JAS 39 Gripen, p.32, Gunnar Lindqvist / Bo Widfeldt, Air Historic Research AB, 2003, ISBN 91-973892-5-0
  3. JAS 39 Gripen, p.32&35, Gunnar Lindqvist / Bo Widfeldt, Air Historic Research AB, 2003, ISBN 91-973892-5-0
  4. Flight International 14 Dec 1972
Bibliography
  • Gunston, Bill (1999). The Development of Piston Aero Engines, 2nd Edition. Sparkford, Somerset, England, UK: Patrick Stephens, Haynes Publishing. ISBN 0-7509-4478-1.
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