Volvo RM12
| RM12 | |
|---|---|
| |
| Type | Turbofan |
| National origin | United States/Sweden |
| Manufacturer | Volvo Aero/GKN Aerospace General Electric |
| First run | 1978 |
| 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 include greater reliability for single-engine operations (including a better tolerance to birdstrikes), increased thrust, and the adoption of a full authority digital engine control (FADEC) system.[1][2]
The fan was completely redesigned to pass more flow for higher thrust and to be more tolerant of a bird-strike. The requirement was for minimal thrust loss, 6% was achieved during a test, after ingesting a half-kilogram (1.1 lb) pigeon-size bird at take-off conditions. It was achieved with thickened first stage blades which deform (causing the thrust loss) but do not fracture or cause downstream damage.[3]
Several subsystems and components were also redesigned to reduce maintenance demands.[4] The air intakes of the engine were designed to minimize radar reflection from the engine fan, reducing the radar cross section of the aircraft overall.[2] 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, a hydromechanical back-up. Hydromechanical backup remains in the new Full Authority Digital Engine Control (FADEC) which Volvo began developing in 1996.[2] 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.[2]
Applications[]
- JAS 39 Gripen
- IAI Nammer (as designed, not built)
Specifications (Volvo RM12)[]
Data from[citation needed]
General characteristics
- Type: Afterburning turbofan
- Length: 4.04 m (159 in)
- Diameter: 0.889 m (35 in), 0.709 m inlet
- Dry weight: 1054 kg (2325 lb)
Components
- Compressor: Axial compressor with 3 fan and 7 compressor stages
- Combustors: annular
- Turbine: 1 low-pressure and 1 high-pressure stage
Performance
- Maximum thrust:
- Overall pressure ratio: 27.5:1
- Bypass ratio: 0.31:1
- Air mass flow: 69 kg/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
See also[]
Related development
Comparable engines
Related lists
References[]
- ^ "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.
- ^ a b c d "Reaktionsmotor 12 - både vacker och stark" [Reaction Engine 12 – both beautiful and strong]. Tech World (in Swedish). SE: IDG. 8 January 2013.
- ^ Larsson, L.; Veno, L. B.; Daub, W. J. (1988). "Development of the F404/RM12 for the JAS 39 Gripen". Volume 2: Aircraft Engine; Marine; Microturbines and Small Turbomachinery. doi:10.1115/88-GT-305. ISBN 978-0-7918-7919-1.
- ^ Volvo Aero (31 January 2008), "Gripen surpasses 100,000 flight hours – Volvo Aero's engine safest in the world", Volvo Financial Services Magyarország, Hungary, archived from the original on 10 January 2014, retrieved 12 January 2014.
External links[]
 |
Wikimedia Commons has media related to Volvo RM12. |
- RM12 page on GKN website
- GE Aviation RM12
- "GKN Aerospace continues Jet engine Biofuel testing" (Press release). 2020-06-26. Archived from the original on 2021-10-09.
- Low-bypass turbofan engines
- 1980s turbofan engines