General Electric GE4


General Electric GE4/J5


The General Electric GE4 turbojet engine was designed in the late 1960s as the powerplant for the Boeing 2707 supersonic transport. The GE4 was a nine-stage, single-shaft, axial-flow turbojet based largely on the General Electric YJ93 which powered the North American XB-70 bomber. The GE4 was the most powerful engine of its era, producing 50,000 lbf (220 kN) dry, and 65,000 lbf (290 kN) with afterburner. The Boeing 2707 was cancelled in 1971, putting an end to further work on the GE4. First run in 1967, only three were built.


Type: Turbojet
Length: 27ft 4 in (833.1cm)
Diameter: 5ft 11 in (180.3cm)
Dry weight: 11,300 lb (5,100 kg)
Compressor: Nine-stage axial
Combustors: Annular straight-through-flow
Turbine: Two-stage axial
Fuel type: Special high-temperature JP-6 Fuel
Maximum thrust: 50,000 lbf (220 kN) (63,200 lbf (281 kN) with afterburning)
Overall pressure ratio: 12.5:1
Turbine inlet temperature: 2,200 ºF (1,204 ºC)
Thrust-to-weight ratio: 6.02
Compressor inlet diameter: 60.6 in (1,539 mm)
Exhaust nozzle diameter: 74.2 in (1,880 mm)
Core airflow: 620 lb (280 kg) per second
Takeoff: 104 dB
Sideline: 117 dB
Approach: 107 dB