General Electric YJ93
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).
|YJ93-GE-3 engine at National Museum of the United States Air Force|
|National origin||United States|
|Manufacturer||General Electric Aircraft Engines|
|Major applications||North American XB-70 Valkyrie|
|Developed into||General Electric GE4|
Design and developmentEdit
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.
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).
The XF-108 interceptor was cancelled outright and the B-70 project was re-oriented to a research project only.
- 24,800 lbf (110 kN) thrust with afterburner.
- Production variant produced in small numbers for the North American XB-70 Valkyrie programme.
- Variant with thrust reverser, 27,200 lbf (121 kN) thrust with afterburner.
- Variant intended for the North American XF-108 Rapier.
- Type: Turbojet with afterburner
- Length: 237 in (6,000 mm)
- Diameter: 52.5 in (1,330 mm)
- Dry weight: 5,000 lb (2,300 kg)
- Compressor: 11-stage axial
- Combustors: Annular with 36 dual fuel nozzles
- Turbine: Two-stage axial
- Fuel type: Special high-temperature JP-6 Fuel to MIL-F-25656
- Oil system: Return oil spray system at 60 psi (410 kPa)
- Kuznetsov NK-32
- Lyulka AL-7
- Kuznetsov NK-144
- Kolesov RD-36-51
- Orenda Iroquois
- Pratt & Whitney J58
- Tumansky R-15
|Wikimedia Commons has media related to General Electric YJ93.|
- Jenkins, Dennis R.; Landis, Tony (2002). North American XB-70A Valkyrie. North Branch [USA]: Specialty Press Publishers and Wholesalers. ISBN 1-58007-056-6.
- 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.
- National Museum of the USAF Retrieved: December 21, 2016
- NB-58A Testbed for General Electric J93 Archived 2008-07-24 at the Wayback Machine
- "Characteristics Summary: F-108A" (PDF). US Air Force. 2 May 1958. Retrieved 15 December 2018.
- "Characteristics Summary: F-108A" (PDF). US Air Force. 15 December 1958. Retrieved 15 December 2018.
- Wilkinson, Paul H. (1966). Aircraft engines of the World 1966/77 (21st ed.). London: Sir Isaac Pitman & Sons Ltd. p. 83.
- "Military Turbojet/Turbofan Specifications". www.jet-engine.net. Retrieved 31 December 2017.