General Electric YJ93

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General Electric YJ93-G-3.jpg
YJ93-GE-3 engine at National Museum of the United States Air Force
Type Turbojet
National origin United States
Manufacturer General Electric Aircraft Engines
Major applications North American XB-70 Valkyrie
Developed into General Electric GE4
YB-58 at Edwards AFB with GE J93 engine pod

The General Electric YJ93 turbojet engine was designed as the powerplant for both the North American XB-70 Valkyrie bomber and the North American XF-108 Rapier interceptor. The YJ93 was a single-shaft axial-flow turbojet with a variable-stator compressor and a fully variable convergent/divergent exhaust nozzle. The maximum sea-level thrust was 28,800 lbf (128 kN).[1]

Design and development[edit]

The YJ93 started life as the General Electric X275, an enlarged version of the General Electric J79 turbojet. This evolved to the X279 when Mach 3 cruise became a requirement, and ultimately became the YJ93.[2]

The engine used a special high-temperature JP-6 fuel. The six YJ93 engines in the XB-70 Valkyrie were capable of producing a thrust to weight ratio of 5:1 allowing for a speed of 2,000 mph (3,200 km/h) (approximately Mach 3) at an altitude of 70,000 feet (21,000 m).[3]

The XF-108 interceptor was cancelled outright and the B-70 project was reoriented to a research project only.[4]


Specifications (YJ93)[edit]

Data from[citation needed]

General characteristics

  • Type: Turbojet
  • Length: 6.2 m (237 in)
  • Diameter: 1.33 m (52.5 in)
  • Dry weight: 3800lb (1,728 kg)


  • Compressor: 11-stage axial
  • Turbine: Two-stage axial
  • Fuel type: Special high-temperature JP-6 Fuel


See also[edit]

Related development
Comparable engines
Related lists


  1. ^ a b c Jenkins, Dennis R. and Tony R. Landis. North American XB-70A Valkyrie WarbirdTech Volume 34. North Branch, Minnesota: Specialty Press, 2002. ISBN 1-58007-056-6.
  2. ^ Jenkins, Dennis R. and Tony R. Landis. Valkyrie: North American's Mach 3 Superbomber. North Branch, Minnesota: Specialty Press, 2005. ISBN 1-58007-072-8.
  3. ^ National Museum of the USAF Retrieved: December 21, 2016
  4. ^ NB-58A Testbed for General Electric J93
  5. ^ a b c Military Turbojet/Turbofan Specifications