General Electric GE4

The General Electric GE4 turbojet engine was designed in the late 1960s as the powerplant for the Boeing 2707 supersonic transport.^[1][2] 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.^[3] 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.^[4] The Boeing 2707 was cancelled in 1971, putting an end to further work on the GE4.

GE4
The General Electric GE4/J5 afterburning turbojet
Type	Turbojet
National origin	United States
Manufacturer	General Electric
First run	1967
Major applications	Boeing 2707 Lockheed L-2000
Produced	1967 – 1972
Number built	3[citation needed]
Developed from	General Electric YJ93

A mock-up of the GE4/J5 single-shaft afterburning turbojet

Specifications (GE4/J5P)

Data from Boeing,^[5] Flight International^[6]

General characteristics

• Type: Afterburning turbojet
• Length: 27ft 4 in (8,331mm)
• Diameter: 5ft 11 in (1,803mm)
• Dry weight: 11,300 lb (5,100 kg)^[7]

Components

• Compressor: Nine-stage axial^[7]
• Combustors: Annular straight-through-flow^[7]
• Turbine: Two-stage axial^[7]
• Fuel type: Special high-temperature JP-6 Fuel

Performance

• Maximum thrust: 50,000 lbf (220 kN) (63,200 lbf (281 kN) with afterburner)
• Overall pressure ratio: 12.5:1^[7]
• Turbine inlet temperature: 2,200 °F (1,204 °C)^[7]
• Thrust-to-weight ratio: 6.02
• Power-to-weight ratio: 6.07^[7]

Other Specifications

• Compressor inlet diameter: 60.6 in (1,539 mm)^[7]
• Exhaust nozzle diameter: 74.2 in (1,880 mm)
• Core airflow: 620 lb (280 kg) per second
• Noise:
  • Takeoff: 104 dB
  • Sideline: 117 dB
  • Approach: 107 dB

See also

Related development

• General Electric J79
• General Electric YJ93

Comparable engines

• Kuznetsov NK-32
• Pratt & Whitney J58
• Rolls-Royce/Snecma Olympus 593

Related lists

• List of aircraft engines