Tuesday, September 21, 2010

General Electric F404

The General Electric F404 was an axial flow, afterburning turbofan engine which was developed by GE to power the F-18 Hornet fighter aircraft. The design of the F404 was based on the YJ101 engine which had been developed for the Northrop YF-17 aircraft. They enlarged the bypass ratio from .20 to .34 to enable higher fuel economy. The engine was designed with a higher priority on reliability than performance. Cost was the main goal in the design of the engine.

The F404 has high resistance to compressor stalls, even at high angles of attack. The reason for this is that it was designed to smooth airflow before it enters the compressor. It requires less than two shop visits per 1,000 flight hours and averages 6,500 hours between in-flight events. The F404 has also shown 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.

Specifications for the General Electric F404

Type: Afterburning turbofan
Length: 154 in (3,912 mm)
Diameter: 35 in (889 mm)
Dry weight: 2,282 lb (1,036 kg)
Compressor: axial compressor with 3 fan and 7 compressor stages
Bypass ratio: 0.34:1
Combustors: annular
Turbine: 1 low-pressure and 1 high-pressure stage
Maximum thrust: 11,000 lbf (48.9 kN) military thrust; 17,700 lbf (78.7 kN) with afterburner
Overall pressure ratio: 26:1
Specific fuel consumption: military thrust: 0.81 lb/(lbf·h) (82.6 kg/(kN·h)
Full afterburner: 1.74 lb/(lbf·h) (177.5 kg/(kN·h))
Thrust-to-weight ratio: 7.8:1 (76.0 N/kg)

GE F404 Test Run