General Electric F404

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F404 turbofan being tested onboard an aircraft carrier
F404 turbofan being tested onboard an aircraft carrier

The General Electric F404, F412, and RM12 are a family of afterburning turbofan engines in the 10,500-19,000 lbf (85 kN) class (static thrust). The series are produced by GE-Aviation. Partners include Volvo Aero, which builds the RM12 variant. The F404 was developed into the larger F412 and F414 turbofans, as well as the experimental GE36 civil propfan.

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[edit] F404 development

GE developed the F404 for the F/A-18 Hornet, shortly after losing the competition for the F-15 Eagle's engine to Pratt & Whitney, and losing the Light Weight Fighter competition to the P&W-powered YF-16. For the F/A-18, GE based the F404 on the YJ101 engine they had developed for the Northrop YF-17, enlarging the bypass ratio from .25 to .4 to enable higher fuel economy. In an unorthodox move, the Navy specified the requirements in order as:

  1. Operability
  2. Reliability and maintainability
  3. Cost
  4. Performance
  5. Weight

GE also analyzed "throttle profiles" and found that pilots were changing throttle settings far more often than engineers previously expected; putting undue stress on the engines. GE also sought with the F404 to avoid compressor stalls and other engine failures, and would respond quickly to control inputs; a common complaint of pilots converting from propeller planes to jets were that early turbojets were not responsive to changes in thrust input. GE executives Frederick A. Larson and Paul Setts, also set the goal that the new engine would be smaller than the F-4's J79, but provide at least as much thrust, and cost half as much as P&W's engine for the F-16.[1]

Due to a fan designed to smooth airflow before it enters the compressor, the F404 has high resistance to compressor stalls, even at high angles of attack. It requires less than two shop visits per 1,000 flight hours and averages 6,500 hours between in-flight events. It also demonstrates high responsiveness to control inputs, spooling from idle to full afterburner in 4 seconds. The engine contains an in-flight engine condition monitoring system (IECMS) that monitors for critical malfunctions and keeps track of parts lifetimes.[2]

GE developed the F110 for the Air Force as an alternative to the Pratt & Whitney F100 for use on the F-16 and F-15 based on the F101 and used F404 technology.[1] GE developed the F404-GE-402 to provide more power for the Swiss export models of the F/A-18. The engine was subsequently adopted by the Kuwait for their Hornets, and eventually by the U.S. on late-model C and D Hornets.[2]

[edit] RM12 development

The Volvo Aero modification of the F404 consists increased performance, greater resistance to bird strikes and designed for single engine use safety criteria.

60% of the engine parts are produced by GE and then shipped to Sweden for final assembly. The fan/compressor discs and case, compressor spool, hubs, seals and the entire afterburner are designed and produced in Sweden.

Maximum thrust is 80.5/54 kN (wet/dry).

[edit] F412 development

GE evolved the F404 into the F412-GE-400 non-afterburning turbofan for the A-12 Avenger II. After the cancellation of the A-12, the research was directed toward an engine for the Super Hornet, which evolved into the F414.

[edit] Applications

F404
Volvo RM12
F412

[edit] Specification (F404-GE-402)

General characteristics

  • Type: Afterburning turbofan
  • Length: 154 in (3,912 mm)
  • Diameter: 35 in (889 mm)
  • Dry weight: 2,282 lb (1,036 kg)

Components

  • Compressor: Axial compressor with 3 fan and 7 compressor stages
  • Bypass ratio: 0.34:1
  • Turbine: 1 low-pressure and 1 high-pressure stage

Performance

[edit] References

  1. ^ Kelly, Orr (1990). Hornet: the inside story of the F/A-18. Novato: Presido Press. ISBN 0-89141-344-8. 
  2. ^ a b Jenkins, Dennis R. (2000). F/A-18 Hornet: A Navy Success Story. New York: McGraw-Hill. ISBN 0071346961. 

[edit] External links

[edit] See also