Search results
Results from the WOW.Com Content Network
The combustor is an impingement cooled annular design. Fuel is delivered to the combustor through an unusual rotating fuel nozzle system, rather than the standard fuel-air mixers or vapourisers. The bypass duct runs the full length of the engine. The FJ44-2A has two additional booster compressor stages.
At take-off, the fan displaces up to 1.3 t (2,900 lb) of air per second, the jet nozzle velocity is almost 1,000 mph (450 m/s) and each high pressure turbine blade generates around 800 hp (600 kW), rotating at 12,500 rpm with their tips reaching 1,200 mph (540 m/s). [3] Rolls-Royce reports the engine is 10 dB quieter than the Trent 700. [15]
The take-off thrust is 5,600 lbf (24.9 kN), flat-rated to ISA +15°C (30°C, 86°F). Chosen to power the Falcon 2000 in 1990, the engine was also first run in May 1990, [1] and it was first flown on a Boeing 727 testbed on 31 August 1992. [2] The CFE738-1 made its inaugural flight on a Falcon 2000 prototype on March 4, 1993.
The fuel was the only heat sink available to the aircraft and after absorbing 40,000 Btu/min (700 kW), [15] keeping everything cool enough from the crew to the exhaust nozzle area indicator, it was supplied to the fuel nozzles at 600 °F (316 °C). [16]
The nozzle is usually convergent with a fixed flow area. Supersonic nozzle — For high nozzle pressure ratios (Nozzle Entry Pressure/Ambient Pressure) a convergent-divergent (de Laval) nozzle is used. The expansion to atmospheric pressure and supersonic gas velocity continues downstream of the throat and produces more thrust.
The increased thrust from the C-D nozzle (2,000 lb, 910 kg at sea-level take-off) on this engine raised the speed from Mach 1.6 to almost 2.0 enabling the Air Force to set a world's speed record of 1,207.6 mph (1,943.4 km/h) which was just below Mach 2 for the temperature on that day. The true worth of the C-D nozzle was not realised on the F ...
Thus civil turbofans today have a low exhaust speed (low specific thrust – net thrust divided by airflow) to keep jet noise to a minimum and to improve fuel efficiency. Consequently, the bypass ratio (bypass flow divided by core flow) is relatively high (ratios from 4:1 up to 8:1 are common), with the Rolls-Royce Trent XWB approaching 10:1. [ 7 ]
The nozzle actuators use engine fuel whereas the F404 uses an engine hydraulic system. "Fueldraulic" actuators for afterburner nozzles have been used since the 1960s on the Pratt & Whitney J58 [5] and Rolls-Royce Turbomeca Adour, [6] for example. They are also used to swivel the VTOL nozzle for the Rolls-Royce LiftSystem. [7]