Volvo RM8
RM8 | |
---|---|
An RM8 on display at the Swedish Air Force Museum | |
Type | Turbofan |
Manufacturer | Volvo Flygmotor/Pratt & Whitney |
First run | 1964 |
Major applications | Saab 37 Viggen |
Developed from | Pratt & Whitney JT8D |
![](http://upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Volvo_Flygmotor_RM8B.jpg/170px-Volvo_Flygmotor_RM8B.jpg)
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]
Variants and applications
- RM8A - AJ 37 Viggen
Since the original engine was constructed for subsonic speeds, most part of the engine had to be redimensioned for the higher Mach-speeds in a military aircraft. Fans and turbine were altered, a new burn-chamber designed and a totally new fuel-control system for both engine and afterburner.[2]
- RM8B - JA 37 Viggen
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 burn-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
- Maximum thrust: 72.2 kN (16,200 lbf) dry, 125 kN (28,100 lbf) wet
- Overall pressure ratio: 16.5:1
- Bypass ratio: 0.97:1
- Turbine inlet temperature: 1,120°C (RM8A)
- Specific fuel consumption: 65 kg/(kN h) (0.64 lb/(lbf h)) dry, 257 kg/(kN h) (2,52 lb/(lbf h)) wet
- Thrust-to-weight ratio: 5.4
See also
Related development
Related lists
References
- Notes
- ^ Gunston, p. 236
- ^ JAS 39 Gripen, p.32, Gunnar Lindqvist / Bo Widfeldt, Air Historic Research AB, 2003, ISBN 91-973892-5-0
- ^ JAS 39 Gripen, p.32&35, Gunnar Lindqvist / Bo Widfeldt, Air Historic Research AB, 2003, ISBN 91-973892-5-0
- ^ 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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External links
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
- Saab Viggen engine trivia
- RM8 history in Swedish