|National origin||Sweden/United States|
|Manufacturer||Volvo Aero/GKN Aerospace
|Major applications||Saab JAS 39 Gripen|
|Developed from||General Electric F404|
The Volvo RM12 is a low-bypass afterburning turbofan jet engine developed for the Saab JAS 39 Gripen fighter. A version of the General Electric F404, the RM12 was produced by Volvo Aero (now GKN Aerospace Engine Systems).
Design and development
Produced by Volvo Aero (now GKN Aerospace Engine Systems), the RM12 is a derivative of the General Electric F404-400. Changes from the standard F404 includes greater reliability for single-engine operations (including more stringent birdstrike protection), increased thrust, and the adoption of a full authority digital engine control (FADEC) system. Several subsystems and components were also redesigned to reduce maintenance demands. The air intakes of the engine were designed to minimize radar reflection from the compression fan, reducing the radar cross section of the aircraft overall. The F404's analogue Engine Control Unit was replaced with the Digital Engine Control – jointly developed by Volvo and GE – which communicates with the cockpit through the digital data buses and, as redundancy, mechanical calculators controlled by a single wire will regulate the fuel-flow into the engine. These mechanical backup systems remain in the new Full Authority Digital Engine Control (FADEC) which Volvo began developing in 1996. General Electric produces 50% of the engine. Elements such as the fan/compressor discs and case, compressor spool, hubs, seals, and afterburner are manufactured in Sweden, final assembly also taking place there.
Specifications (Volvo RM12)
- Type: Afterburning turbofan
- Length: 4.04 m (159 in)
- Diameter: 0.889 m (35 in)
- Dry weight:
- Compressor: Axial compressor with 3 fan and 7 compressor stages
- Combustors: annular
- Turbine: 1 low-pressure and 1 high-pressure stage
- Maximum thrust:
- Overall pressure ratio: 27.5:1
- Bypass ratio: 0.31:1
- Air mass flow: 68kg/s
- Specific fuel consumption:
- Military thrust: 23.9 mg/(N s) (0.844 lb/(lbf hr))
- Full afterburner: 50.6 mg/(N s) (1.79 lb/(lbf hr))
- Thrust-to-weight ratio: 7.8:1 (76.0 N/kgf)
- Related development
- Comparable engines
- Related lists
- "Resonance problem hits Gripen Engine", Flight International, London, UK: Reed Business Information, 145 (4406): 15, 2–8 February 1994, ISSN 0015-3710, archived from the original on 16 December 2013, retrieved 16 December 2013.
- "Reaktionsmotor 12 - både vacker och stark" [Reaction Engine 12 – both beautiful and strong]. Tech World (in Swedish). SE: IDG. 8 January 2013.
- Volvo Aero (31 January 2008), "Gripen surpasses 100,000 flight hours – Volvo Aero's engine safest in the world", Volvo Financial Services Magyarország, Hungary.
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