General Electric J85
| J85 | |
|---|---|
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| A General Electric J85-5 |
The General Electric J85 is a small single-shaft turbojet engine. Military versions produce up to Script error: No such module "convert". of thrust dry; afterburning variants can reach up to Script error: No such module "convert".. The engine, depending upon additional equipment and specific model, weighs from Script error: No such module "convert".. It is one of GE's most successful and longest in service military jet engines, with the civilian versions having logged over 16.5 million hours of operation. The United States Air Force plans to continue using the J85 in aircraft through 2040.[1] Civilian models, known as the CJ610, are similar but supplied without an afterburner and are identical to non-afterburning J85 variants, while the CF700 adds a rear-mounted fan for improved fuel economy.
Design and development
The J85 was originally designed to power a large decoy missile, the McDonnell ADM-20 Quail. The Quail was designed to be released from a B-52 Stratofortress in-flight and fly for long distances in formation with the launch aircraft, multiplying the number of targets facing the SA-2 surface-to-air missile operators on the ground. This mission demanded a small engine that could nevertheless provide enough power to keep up with the jet bomber. Like the similar Armstrong Siddeley Viper being built in the UK, the engine on a Quail drone had no need to last for extended periods of time, so therefore could be built of low-quality materials.
The fit was a success on the Quail, but again like the Viper it was later built with normal grade materials and subsequently used to power small jet aircraft, including the Northrop T-38 Talon, Northrop F-5, Canadair CT-114 Tutor, and Cessna A-37 Dragonfly light attack aircraft. More recently, J85s have powered the Scaled Composites White Knight aircraft, the carrier for the Scaled Composites SpaceShipOne spacecraft, and the Me 262 Project.
The basic engine design is quite small, about Script error: No such module "convert". in diameter, and Script error: No such module "convert". long. It features an eight-stage axial-flow compressor powered by two turbine stages, and is capable of generating up to Script error: No such module "convert". of dry thrust, or more with an afterburner. At full throttle at sea level, this engine, without afterburner, consumes approximately Script error: No such module "convert". of fuel per hour. At cruise altitude and power, it consumes approximately Script error: No such module "convert". per hour.
Several variants were produced.
The most advanced variant in the J85 series is the J85-21 model designed specifically for the F-5E/F during its development process.[2]
The J85-21 design replaces AM 355 chromium nickel molybdenum stainless steel alloy, used by previous J85 models for compressor rotors and blades, with a titanium alloy. Its inlet diameter was increased from Script error: No such module "convert". to Script error: No such module "convert"., and it included an added stage ahead of the base 8-stage compressor for a total of 9 stages. Its multiple disk rotors were replaced with a single-spool rotor, thus improving dry thrust to Script error: No such module "convert". and wet thrust to Script error: No such module "convert". while reducing mechanical complexity along with the weight gain of the J85-21 model.[2]
More than 12,000 J85 engines had been built by the time production ended in 1988.[3]
Iranian reverse engineering
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The Iranian Ministry of Defense constructed a new engine based on the General Electric J85-GE-21B named "OWJ" and presented it at a defense exhibition on 22 August 2016.[4][5][6][7]
The Owj engine has been used in several Iranian products like Kowsar, Saeghe and Azarakhsh fighter jets or Yasin training jet.[8][9]
Variants
- J85-GE-1
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- J85-GE-2
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- J85-GE-3
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- J85-GE-4
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- J85-GE-4A
- Script error: No such module "convert". thrust
- J85-GE-5
- Script error: No such module "convert". dry thrust; Script error: No such module "convert". afterburning thrust
- J85-GE-5A
- Script error: No such module "convert". dry thrust; Script error: No such module "convert". afterburning thrust
- J85-GE-7
- Script error: No such module "convert". thrust
- J85-GE-12
- Script error: No such module "convert". thrust
- J85-GE-13
- Script error: No such module "convert"., dry thrust; Script error: No such module "convert". afterburning thrust[10]
- J85-GE-13A
- License built for the Fiat G.91Y, Script error: No such module "convert"., dry thrust; Script error: No such module "convert". afterburning thrust[2]
- J85-GE-15
- Script error: No such module "convert". dry thrust; Script error: No such module "convert". afterburning thrust[2]
- J85-CAN-15
- Orenda manufactured J85-GE-15 for the Canadair CF-116, Script error: No such module "convert". dry thrust; Script error: No such module "convert". afterburning thrust[2]
- J85-GE-17
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- J85-GE-17A
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- J85-GE-17B
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- J85-GE-17C
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- J85-GE-19
- Script error: No such module "convert". dry thrust
- J85-GE-21A
- Script error: No such module "convert". dry thrust; Script error: No such module "convert". afterburning thrust.[10]
- J85-GE-J1A
- Script error: No such module "convert". dry thrust; Script error: No such module "convert". afterburning thrust
- J85-GE-J2
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- J85-GE-J4
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- J85-CAN-40
- Manufactured by Orenda for the Canadair CT-114 Tutor, Script error: No such module "convert". thrust[2]
- J85-GE-100
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Applications
- Bell X-14A/B
- Boom XB-1 demonstrator[12]
- Canadair CT-114 Tutor
- Canadair CF-5
- Cessna A-37 Dragonfly
- HESA Yasin (without afterburner)
- HESA Kowsar (with afterburner)
- Fairchild C-123 Provider
- Fairchild AC-119K
- Fiat G.91Y
- Lockheed Have Blue
- McDonnell ADM-20 Quail decoy missile
- North American Rockwell OV-10 Bronco - OV-10B(Z) target tug variant, the engine in addition to its turboprops[13]
- North American T-2 Buckeye
- Northrop F-5
- Northrop T-38 Talon
- Republic AP-100
- Ryan MQM-34D Mod II target drone
- Ryan XV-5 Vertifan
- Saab 105Ö
- Scaled Composites White Knight
Other
- American Challenge water speed record jet-powered boat - Two J85-GE-21s[14]
- Hermeus experimental turbine-based combined cycle "Chimera" turboramjet engine - J85-21 turbojet core[15]
- Boom Technology XB-1 "baby boom" Experimental supersonic aircraft. it uses 3 J85-15 turbojet engines[16]
Specifications (J85-GE-21)
General characteristics
- Type: afterburning turbojet engine
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- Diameter: Script error: No such module "convert". inlet
- Dry weight: Script error: No such module "convert".
Components
- Compressor: single-spool 9 axial stages
- Combustors: annular
- Turbine: 2 stages
- Fuel type: jet fuel
Performance
- Maximum thrust: Script error: No such module "convert". dry thrust / Script error: No such module "convert". afterburner thrust
- Overall pressure ratio: 8.3:1 (J85-21 A~C model)
- Air mass flow: Script error: No such module "convert". per second
- Turbine inlet temperature: Script error: No such module "convert".
- Specific fuel consumption: Script error: No such module "convert". dry thrust / Script error: No such module "convert". afterburner thrust
- Thrust-to-weight ratio: 5.25 dry / 7.3 afterburner
See also
Related development
Comparable engines
Related lists
References
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- ↑ a b c d e f g h i Defense Technical Information Center Compilation Part Notice dtic.mil
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- ↑ Engine Data Tables Springer
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External links
- GE J85 product page
- J85 picture
- "G.E.'s Small Turbojet" a 1959 Flight article
