Volvo RM12

Summary

RM12
Gripen 5.jpg
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

Specifications (Volvo RM12)

View showing engine variable exhaust nozzle

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

Performance

See also

Related development

Comparable engines

Related lists

References

  1. ^ "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.
  2. ^ 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.
  3. ^ 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.
  4. ^ 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

  • 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.