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The General Electric J85 is a small single-shaft turbojet engine. Military versions produce up to 2,950 lbf (13.1 kN) of thrust dry, afterburning variants can reach up to 5,000 lbf (22 kN). The engine, depending upon additional equipment and specific model, weighs from 300 to 500 pounds (140 to 230 kg). 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. Civilian models, known as the CJ610, are similar but supplied without an afterburner, while the CF700 adds a rear-mounted fan for improved fuel economy.

Contents

1 Design and development

1.1 Iranian reverse engineering

2 Variants 3 Applications

3.1 Other

4 Specifications

4.1 General characteristics 4.2 Components 4.3 Performance

5 See also 6 References 7 External links

Design and development[edit] 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 England, 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 18 inches (46 cm) in diameter, and 45 inches (110 cm) long.[citation needed] It features an eight-stage axial-flow compressor powered by two turbine stages, and is capable of generating up to 2,950 lbf (13.1 kN) of dry thrust, or more with an afterburner. At full throttle at sea level, this engine, without afterburner, consumes approximately 400 US gallons (1,500 L) of fuel per hour. At cruise altitude and power, it consumes approximately 100 US gal (380 L) per hour. Several variants were produced. The J85-21 variant added a stage ahead of the base 8-stage compressor for a total of 9 stages, improving thrust. More than 12,000 J85 engines had been built by the time production ended in 1988.[1] Iranian reverse engineering[edit] See also: Iran Aviation Industries Organization The Iranian Ministry of Defense constructed a new engine based on the General Electric J85 named "OWJ". The engine was presented at a defense exhibition on 22 August 2016.[2] Variants[edit]

J85-GE-1 2,600 lbf (12 kN) thrust J85-GE-2 2,850 lbf (12.7 kN) thrust J85-GE-3 2,450 lbf (10.9 kN) thrust J85-GE-4 2,950 lbf (13.1 kN) thrust J85-GE-5 2,400 lbf (11 kN) thrust, 3,600 lbf (16 kN) afterburning thrust J85-GE-5A 3,850 lbf (17.1 kN) afterburning thrust J85-GE-7 2,450 lbf (10.9 kN) thrust J85-GE-12

J85-GE-13 4,080 lbf (18.1 kN), 4,850 lbf (21.6 kN) thrust J85-GE-15 4,300 lbf (19 kN) thrust J85-CAN-15 Orenda manufactured J85-GE-15 for the Canadair CF-116 4,300 lbf (19 kN) thrust J85-GE-17A 2,850 lbf (12.7 kN) thrust J85-GE-19

J85-GE-21 3,500 lbf (16 kN) military thrust; 5,000 lbf (22 kN) afterburning thrust. J85-GE-J1A 5,000 lbf (22 kN) thrust J85-GE-J2 military version of the CJ610, similar to the GE-7, 2,850 lbf (12.7 kN) thrust. J85-GE-J4

J85-CAN-40 Manufactured by Orenda for the Canadair CT-114 Tutor, 2,650 lbf (11.8 kN) thrust

Applications[edit]

Scaled Composites White Knight sporting two General Electric J85 afterburning engines

Boom Technology XB-1 "Baby Boom" demonstrator[3] Canadair CL-41 Tutor Canadair CF-5 Cessna A-37 Dragonfly Fairchild C-123 Provider Fairchild AC-119K Fiat G.91Y McDonnell ADM-20 Quail decoy missile MQM-34D Mod II target drone North American OV-10B(Z) Bronco North American T-2 Buckeye Northrop F-5 Northrop T-38 Talon Ryan XV-5 Vertifan Saab 105Ö Scaled Composites White Knight Viperjet MKII

Other[edit]

American Challenge water speed record jet-powered boat - Two J85-GE-21s[4]

Specifications[edit]

A J85 engine sectioned for display

Data from[citation needed] General characteristics

Type: Turbojet engine (with or without afterburner) Length: 45.4–51.1 in (115–130 cm) without afterburner (depending on accessory equipment installed) Diameter: 17.7 in (45 cm) Dry weight: 396–421 lb (180–191 kg) (depending on accessory equipment installed)

Components

Compressor: 8 stages (9 in J85-21) axial Combustors: annular Turbine: 2 stages Fuel type: jet fuel

Performance

Maximum thrust: 2,850–3,100 lbf (12.7–13.8 kN) (dry) Overall pressure ratio: 8.3 Air mass flow: 45 lb (20 kg) per second Turbine inlet temperature: 977C Specific fuel consumption: 0.96 - 0.97 lb/(lbf·h) (27 g/kN·s) Thrust-to-weight ratio: 7.5 (-21), 6.6 (-5), 6.8 (-13), 7 (-15)

See also[edit] Related development

General Electric CJ610 General Electric CF700

Comparable engines

Armstrong Siddeley Viper Continental J69 Fairchild J83 Rolls-Royce Soar

Related lists

List of aircraft engines

References[edit]

^ [1] ^ Iran unveil indigenous turbojet engine (Aviation Analysis Wing.) ^ Norris, Guy (18 June 2017). ""Baby Boom" Demonstrator Passes Design Review". Aviation Week. Retrieved 21 March 2018.  ^ 400 Mph On Water - Popular Mechanics Archived 2007-09-30 at the Wayback Machine.

Gunston, Bill (2006). World Encyclopedia of Aero Engines, 5th Edition. Phoenix Mill, Gloucestershire, England, UK: Sutton Publishing Limited. ISBN 0-7509-4479-X. 

External links[edit]

Wikimedia Commons has media related to General Electric J85.

GE J85 product page J85 picture "G.E.'s Small Turbojet" a 1959 Flight article

v t e

General Electric aircraft engines

Turbojets

CJ610 CJ805 GE1 GE4/J5P J31 J33 J35 J47 J73 J79 J85 J87 YJ93 J97 YJ101

Turbofans

CF6 CF34 CF700 CFE738† CFM56† CJ805-23 F101 F108† F110 F118 YF120 F136† F404/F412/RM12 F414 GE90 GE9X GEnx GP7000† HF120† LEAP† Passport RM12 TF34 TF39

Turboprops/Turboshafts

Catalyst CT7 CT58 CT64 GE27 GE36 GE38 H80 T31 T58 T64 T407 T408 T700 T901

Aeroderivative gas turbine engines

LM500 LM1500 LM1600 LM2500 LM6000 LMS100 LV100†

† Joint development aeroengines

v t e

United States military gas turbine aircraft engine designation system

Turbojets

J30 J31 J32 J33 J34 J35 J36 J37 XJ38 J39 J40 XJ41 J42 J43 J44 J45 J46 J47 J48 XJ49 J51 J52 J53 J54 J55 J56 J57 J58 J59 J60 J61 J63 J65 J67 J69 J71 J73 J75 J79 J81 J83 J85 J87 J89 J91 YJ93 J95 J97 J99 J100 YJ101 J102 J400 J401 J402 J403 J700

Turboprops/ Turboshafts

T30 T31 T33 T34 T35 T36 T37 T38 T39 T40 T41 T42 T43 T44 T45 T46 T47 T48 T49 T50 T51 T52 T53 T54 T55 T56 T57 T58 T60 T61 T62 T63 T64 T65 T66 T67 T68 T69 T70 T71 T72 T73 T74 T76 T78 T80 T100 T101 T400 T405 T406 T407 T408 T700 T701 T702 T703 T706 T708 T800 T900 T901

Turbofans

TF30 TF31 TF32 TF33 TF34 TF35 TF37 TF39 TF41 F100 F101 F102 F103 F104 F105 F106 F107 F108 F109 F110 F112 F113 F117 F118 F119 YF120 F121 F122 F124 F125 F126 F127 F128 F129 F130 F135 F136 F137 F138 F400 F401 F402 F404 F405 F408 F4