General Electric J79

J79
	J79 on display at the National Museum of the United States Air Force
Type	Afterburning turbojet
National origin	United States
Manufacturer	General Electric Aircraft Engines
First run	20 May 1955 (first flight)
Major applications	Convair B-58 Hustler ; IAI Kfir ; Lockheed F-104 Starfighter ; McDonnell Douglas F-4 Phantom II ; North American A-5 Vigilante
Number built	>17,000
Developed from	General Electric J73
Variants	General Electric CJ805
Developed into	General Electric CJ805-23

The General Electric J79 is an axial-flow turbojet engine built for use in a variety of fighter and bomber aircraft and a supersonic cruise missile. The J79 was produced by General Electric Aircraft Engines in the United States, and under license by several other companies worldwide. Among its major uses was the F-104 Starfighter, B-58 Hustler, F-4 Phantom II, A-5 Vigilante and IAI Kfir.

A commercial version, designated the CJ805, powered the Convair 880, while an aft-turbofan derivative, the CJ805-23, powered the Convair 990 airliners and a single Sud Aviation Caravelle intended to demonstrate to the U.S. market the benefits of a bypass engine over the existing Avon turbojet.

In 1959 the gas generator of the J79 was developed as a stationary 10MW-class (13,000 bhp) free-turbine turboshaft engine for naval power, power generation, and industrial use, called the LM1500.^[2]^[3] Its first application was in the research hydrofoil USS Plainview.

Development[]

By the late 1940s, jet engine design had progressed to the point where further progress was limited by the performance of the compressor. It is difficult to produce a design that runs efficiently under a wide variety of conditions, and those conditions change dramatically in practical operation as the aircraft starts at rest on the ground and later flies near Mach speed at high altitudes. To avoid compressor stalls the overall pressure ratio had to be limited. Early wartime engines like the Junkers Jumo 004 and Rolls-Royce Welland had ratios just over 3:1.

Axial compressors work by accelerating air over a series of airfoils, one set connected to a rotating shaft, the "rotor", and a second set connected to the outer frame of the engine, the "stators". It is the physical relationship between these two components and their relative speed that tunes the compressor for certain conditions. Early models of the Rolls-Royce Avon, then still known as the AJ65, tended to break off the blades in the first stages of its compressor when running at low speed. In 1949, RR built an experimental version of this engine where several rows of stator blades at the forward low-pressure section could be rotated to lower the compression while running at low speed. This solution proved to have several difficult problems, including the leakage of high-pressure air into the bearings on the inside of the engine. They ultimately abandoned the concept and replaced it with a simpler system with a single variable inlet and a system to "bleed" air out of the early stages of the compressor during startup.^[4] This allowed the engine to enter service with a compression ratio of 6.2:1, a great advance that was further improved in later versions to as high as 8.8.^[5] This proved extremely influential, and many engines of the era used these concepts, including the General Electric J73.

In 1951, GE decided to try their hand at the variable stator design. A team led by Gerhard Neumann produced a prototype with the inlet and first five stages of the 14-stage stator being variable. Testing of the design, known as X24A,^[6] was completed in May 1952. Soon after, the Air Force put out a contract for a new engine with approximately 14,000 pounds thrust to power a new supersonic bomber design. The Aircraft Gas Turbine Division lead, C.W. 'Jim' LaPierre, formed two teams to consider an engine that could run for extended times at Mach 2.0 while still offering good fuel economy in a cruise at Mach 0.9. Gerhard Neumann was put in charge of a team using the variable stator concept of the X24, while Chapman Walker led a parallel effort using a two-spool design. A comparison of the resulting designs showed the variable stator was both lighter, simpler and had a smaller diameter.^[4]^[7]

GE won the Air Force contract on 3 December 1953, and was awarded contract MX2118 intended to power the Convair B-58 Hustler. The two other engines offered by GE, an advanced version of the existing J73 and a much larger design known as the J77, were both canceled. The contract started with a prototype of the new design, GOL-1590. It ran for the first time on 16 December 1953, but quickly accelerated out of control and was damaged. The engine was repaired and ran again three weeks later, and quickly demonstrated excellent performance that led the team to question the accuracy of their test equipment. The first prototype of the production version, XJ-79, ran on 8 June 1954.^[4]

The first flight of the engine was on 20 May 1955 where the engine was placed in the bomb bay of a J47-powered B-45C (48-009). The J79 was lowered from the bomb bay and the four J47s were shut down leaving the B-45 flying on the single J79.^[8] The first flight after the 50-hour qualification test was on 8 December 1955, powering the second pre-production Douglas F4D Skyray, with the J79 in place of its original Westinghouse J40 engine as part of the General Electric development and qualification program. The YF-104 was the next airplane to fly with the J79 followed by a re-engined Grumman F11F Tiger in a Navy-sponsored program to gain experience with the engine before the first flight of the F4H (F-4).

The J79 was used on the F-104 Starfighter, B-58 Hustler, F-4 Phantom II, A-5 Vigilante, IAI Kfir and SSM-N-9 Regulus II supersonic cruise missile. It was produced for more than 30 years. Over 17,000 J79s were built in the US, and under license in Belgium, Canada, Germany, Israel, Italy, and Japan. A downgraded version of the F-16 Fighting Falcon with a J79 was proposed as a low-cost fighter for export, and though a prototype aircraft was flown, it found no customers.

The J79 was replaced by the late 1960s in new fighter designs by afterburning turbofans such as the Pratt & Whitney TF30 used in the F-111 and F-14, and newer generation turbofans with the Pratt & Whitney F100 used in the F-15 Eagle which give better cruise fuel efficiency by-passing air around the core of the engine.

For their part in designing the J79, Gerhard Neumann and Neil Burgess of General Electric Aircraft Engines were jointly awarded the Collier Trophy in 1958, also sharing the honor with Clarence Johnson (Lockheed F-104) and the US Air Force (Flight Records).^[9]

Design[]

Sectioned compressor stage of a J79.

The compressor blades and vanes are made of 403 stainless steel, except for the -3B and -7A variants, which have A286 vanes at stages 7 through 17. The compressor rotor is made of Lapelloy, B5F5 and titanium.^[10] The J79 makes a particular howling sound at certain throttle settings. This strange feature led to the NASA operated F-104B Starfighter, N819NA, being named Howling Howland.^[11] Early engines also produced noticeable quantities of smoke, especially at mid-throttle/cruise settings, a disadvantage in combat aircraft making them vulnerable to visual detection. Later models were redesigned to be "smokeless".

The turboshaft counterpart to the J79 is the General Electric LM1500, used for land and marine applications. Many J79 derived engines have found uses as gas turbine power generators in remote locations, in applications such as powering pipelines.

The J79 has two commercial derivatives: CJ805-3 (a non-afterburning engine, fitted with thrust reverser and sound suppressor), and the CJ805-23 (with a free-wheeling aft fan and thrust reverser) fitted to the Convair CV-880 and the Convair CV-990 respectively.

With air-start systems gas turbine engine compressor spools are rotated by the action of a large volume of compressed air acting directly on the compressor blades or driving the engine through a small, geared turbine motor.

Variants[]

GE-J79-3 and Lockheed YF-104A Starfighter

XJ79-GE-1: Prototype. First ground static test run on 8 June 1954 produced 14,350 lbf (63.83 kN) with afterburner.^[12]
YJ79-GE-1: Flight test engines were designated YJ79-GE-1.
J79-GE-2: Powered the McDonnell F-4H-1 Phantom (F-4A), 16,100 lbf (71.62 kN) of afterburner thrust.
J79-GE-2A: essentially similar to the -2
J79-GE-3: Used in the YF-104A, F-104A and the Grumman F11F-1F Super Tiger
J79-GE-3A: YF-104A, F-104A and F-104B.
J79-GE-3B: F-104A and F-104B.
J79-GE-5A: Convair B-58 Hustler 15,600 lbf (69.39 kN) with afterburner.
J79-GE-5B: Convair B-58 Hustler 15,600 lbf (69.39 kN) with afterburner.
J79-GE-5C

J79-15A at the USAF Museum.

J79-GE-7

F-104C, F-104D and F-104F.

J79-GE-7A

F-104C, F-104D and F-104F.

J79-OEL-7: Licensed production GE-7 manufactured by Orenda Engines to power the Canadair CF-104.

J79-GE-8

North American A-5 Vigilante and F4H-1 (F-4B) with 16,950 lbf (75.4 kN) of afterburner thrust

J79-GE-8A

Sub-variant of the -8

J79-GE-8B

Sub-variant of the -8

J79-GE-10

F-4J, 17,900 lbf (79.379 kN) of afterburner thrust.

J79-GE-11

J79-GE-11A

F-104G and TF-104G. 15,600 lbf (69 kN) with afterburner. Many -11 engines were licensed manufactured in Europe as part of the large F-104 consortium production programme, Alfa Romeo, Fiat and Fabrique Nationale being the main suppliers for the project.

J79-IHI-11A: Licensed production GE-11A, built in Japan by Ishikawajima-Harima Heavy Industries Co., Ltd to power their similarly licensed built F-104J and F-104DJ Starfighters.
J79-MTU-J1K: Licensed built and improved version of the GE-11A manufactured by MTU Aero Engines in Germany.

J79-GE-15: F-4C, RF-4C, F-4D; with 17,000 lbf (75.6kN) of afterburner thrust.
J79-GE-17: F-4E, RF-4E, F-4EJ, F-4F, F-4G; with 17,900 lbf (80 kN) of afterburner thrust.
J79-GE-19: Aeritalia F-104S; also retrofitted to F-104A's of the 319th FIS.
J79-GE-J1E: License-built in Israel by Beit Shemesh Engines Ltd. (BSEL)^{[citation needed]} with 18,750 lbf (83.40 kN) afterburning thrust for the IAI Kfir.
J79-GE-119: F-16/79

Applications[]

J79 powered Convair B-58 Hustler

Aircraft

Convair B-58 Hustler
General Dynamics F-16/79
Grumman F11F-1F Super Tiger
IAI Kfir
Lockheed F-104 Starfighter
McDonnell Douglas F-4 Phantom II
North American A-5 Vigilante
Northrop X-21
SSM-N-9/RGM-15 Regulus II

Land speed record cars

Art Arfons' "Green Monster"
Craig Breedlove's "Spirit of America - Sonic 1"
North American Eagle Project

Specifications (J79-GE-17)[]

J79 with components labeled

Cutaway view of an air-start motor of a General Electric J79 turbojet

Data from ^[13]^[14]

General characteristics

Type: Afterburning turbojet engine
Length: 208.69 in (5.301 m)
Diameter: 39.06 in (0.992 m)
Dry weight: 3,835 lb (1,740 kg)

Components

Compressor: single-spool 17-stage axial compressor, with one row of variable inlet guide vanes (VIGV's) followed by 6 rows of variable stator vanes
Combustors: cannular
Turbine: 3-stage
Fuel type: JP-4, JP-5

Performance

Maximum thrust: 11,870 lbf (52.8 kN) dry; 17,900 lbf (80 kN) with afterburner
Overall pressure ratio: 13.5:1
Air mass flow: 170 lb/s (77 kg/s)
Turbine inlet temperature: 1,710 °F (930 °C; 1,210 K)
Specific fuel consumption: 1.965 lb/(lbf⋅h) or 55.7 g/(kN⋅s) with afterburner, 0.84 lb/(lbf⋅h) or 24 g/(kN⋅s) at military thrust
Thrust-to-weight ratio: 4.6

References[]

Notes[]

^ General Electric - Aviation History Retrieved: 7 April 2008
^ Stoeckly, E. E. (1 April 1966). "Development of the General Electric LM 1500 Gas Turbine as a Marine Power Plant". . 88 (2): 144–152. doi:10.1115/1.3678497.
^ "Taking it back to 1959 when the J79 turbojet engine was reconfigured as the LM1500". General Electric. 1959.
^ Jump up to: ^a ^b ^c Brimer, Matt (26 August 2017). Designing Simplicity to Achieve Technological Improvement: The General Electric J79 Turbojet Engine; Innovations, Achievements and Effects (Technical report). University of Missouri, St. Louis.
^ Rolls-Royce Aero Engines" Bill Gunston, Patrick Stephens Ltd. 1989, ISBN 1-85260-037-3, p.133
^ "seven decades of progress" General Electric, Aero Publishers Inc. 1979, ISBN 0-8168-8355-6, p.89
^ "Starting Something Big" Robert V. Garvin, AIAA Inc. 1998, ISBN 1-56347289-9, p.13
^ Pace 1992 p. 67.
^ Collier Trophy winners, 1950–1959 Archived 2008-12-11 at the Wayback Machine, National Aeronautic Association. Retrieved: 7 April 2008
^ Taylor, John (1975). Jane's All The World's Aircraft 1974-1975. p. 747.
^ Bashow 1986, p. 16.
^ Pace 1992, p. 69.
^ Taylor, John (1975). Jane's All The World's Aircraft 1974-1975. pp. 747–748.
^ AgentJayZ (2010). "J79 - Turbine Engines: A Closer Look". Retrieved August 25, 2020.

Bibliography[]

Neumann, Gerhard (June 1984). Herman the German. William Morrow & Co. p. 269. ISBN 978-0-688-01682-1. The former enemy alien and Air Corps G.I. whose inventive skills and maverick management techniques made jet engine history
Pace, Steve. Lockheed F-104 Starfighter. Osceola, Wisconsin: Motorbooks International, 1992. ISBN 0-87938-608-8.
Bashow, David L. Starfighter: A Loving Retrospective of the CF-104 Era in Canadian Fighter Aviation, 1961–1986. Stoney Creek, Ontario: Fortress Publications Inc., 1990. ISBN 0-919195-12-1.
Gunston, Bill. Fighters of the Fifties. Cambridge, England. Patrick Stephens Limited, 1981. ISBN 0-85059-463-4.
Williams, Nick and Steve Ginter "Douglas F4D Skyray". Simi Valley, California: Ginter, 1986. ISBN 0-942612-13-2.

External links[]

[1] General Electric - Aviation History Retrieved: 7 April 2008

[2] Stoeckly, E. E. (1 April 1966). "Development of the General Electric LM 1500 Gas Turbine as a Marine Power Plant". . 88 (2): 144–152. doi:10.1115/1.3678497.

[3] "Taking it back to 1959 when the J79 turbojet engine was reconfigured as the LM1500". General Electric. 1959.

[history79-4] Jump up to: ^a ^b ^c Brimer, Matt (26 August 2017). Designing Simplicity to Achieve Technological Improvement: The General Electric J79 Turbojet Engine; Innovations, Achievements and Effects (Technical report). University of Missouri, St. Louis.

[5] Rolls-Royce Aero Engines" Bill Gunston, Patrick Stephens Ltd. 1989, ISBN 1-85260-037-3, p.133

[6] "seven decades of progress" General Electric, Aero Publishers Inc. 1979, ISBN 0-8168-8355-6, p.89

[7] "Starting Something Big" Robert V. Garvin, AIAA Inc. 1998, ISBN 1-56347289-9, p.13

[8] Pace 1992 p. 67.

[9] Collier Trophy winners, 1950–1959 Archived 2008-12-11 at the Wayback Machine, National Aeronautic Association. Retrieved: 7 April 2008

[10] Taylor, John (1975). Jane's All The World's Aircraft 1974-1975. p. 747.

[Bashow_p._16-11] Bashow 1986, p. 16.

[12] Pace 1992, p. 69.

[13] Taylor, John (1975). Jane's All The World's Aircraft 1974-1975. pp. 747–748.

[AgentJayZJ79-14] AgentJayZ (2010). "J79 - Turbine Engines: A Closer Look". Retrieved August 25, 2020.

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[14]

show v t General Electric aircraft engines
Turbojets	CJ610 CJ805 GE4/J5P J31 J33 J35 J47 J73 J79 J85 J87 YJ93 J97 YJ101
Turbofans	Affinity CF6 CF34 CF700 CFE738† CFM56† CJ805-23 F101 F108† F110 F118 YF120 F136† F404/F412 F414 GE90 GE9X GEnx GP7000† HF120† LEAP† Passport RM12† TF34 TF39 XA100
Turboprops/Turboshafts	Catalyst CT7 CT58 CT64 GE27 GE36 GE38 H-Series T31 T58 T64 T407 T408 T700 T901
Aeroderivative gas turbine engines	LM500 LM1500 LM1600 LM2500 LM6000 LM9000 LMS100
† Joint development aeroengines

show v t 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 J52 J54 J55 J57 J58 J60 J65 J67 J69 J71 J73 J75 J79 J81 J83 J85 J87 YJ93 J97 J100 YJ101 J102 J400 J402 J403 J700
Turboprops/ Turboshafts	T31 T33 T34 T35 T36 T37 T38 T39 T40 T41 T44 T46 T47 T49 T50 T51 T53 T54 T55 T56 (variants) T57 T58 T60 T61 T62 T63 T64 T65 T66 T67 T72 T73 T74 T76 T101 T400 T406 T407 T408 T700 T701 T702 T703 T706 LHTEC T800 APW T800 T900 T901
Turbofans	TF30 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 F401 F402 F404 F405 F408 F412 F414
Adaptive cycle engines	XA100 XA101

show v t United States Air Force system numbers
100–199	100 101 P 102 103 104 105 106¹ 107 A-1 A-2 108¹ 109¹ 110 111¹ 112 113¹ 114¹ 115¹ 116¹ 117 M 118 A 119 C/F E T Y 120 121 122 123 124 125 127¹ 129 131 132 133 134¹ 136¹ 137¹ 138 139 140 141¹ 142 143–197¹ 199 B C D
200–299	200 201 A/L B/W E 202 203¹ 204 205 206 207¹ 208 209¹ 210 211¹ 213 214 215¹ 216 217 218 219¹ 220 221 222 A 223¹ 224 225¹ 226 227–238¹ 239 240–278¹ 279 280–298¹
300–399	300 301¹ 302 303 304¹ 305¹ 306 A/L B 307 308 309 310¹ 311¹ 312¹ 313¹ 314 315 A-1 A-2 316 318¹ 319 320¹ 321 322¹ 324 L M/N 326 327 E 328 E 329 F 330¹ 331¹ 332¹ 333¹ 334¹ 335 336 337 338–379¹ 380 A/B/E/F/N P 381–397¹ 399
400–499	400 B/C/N E G/H M 401 402 403¹ 405 406¹ 408¹ 409¹ 410 E 411 E L 413 414 416 L M (I) 418 419¹ 420 L/W 421¹ 422 423 424 425 426 L 427 L 428 L 429 431 434 435 L 436 441 A L 442 443 444¹ 445 446 447 448¹ 449¹ 450 451 L 452 453 454¹ 457¹ 460 L 462 463 464 465 468 471 L (I) L (II) 474 L N 475¹ 476 E 477 478 A 479¹ 481 L 482 E M/Z 484 485 Z 487 488 490 491¹ 493 494 495 496 497 L 498 C E L 499
500–599	501–519¹ 521–529¹ 531–541¹ 543–549¹ 550 551–559¹ 560 561–569¹ 571–579¹ 580 581–589¹ 591 593–599¹
600–699	601 A 602 A 603 A 605 606 607 608¹ 609 610¹ 611¹ 612¹ 613¹ 615¹ 616 617¹ 619¹ 620 621 A/B (I) 622 624 626¹ 628¹ 629¹ 630¹ 631¹ 634 A B 636¹ 637¹ 638 641 644¹ 645¹ 646¹ 647¹ 648 A P 649 P 653¹ 654¹ 655 656 657¹ 658¹ 659¹ 662¹ 663¹ 665 666 669¹ 671¹ 672 673¹ 676¹ 677¹ 678¹ 681 682¹ 683 A V 684¹ 687 P 688¹ 689¹ 691 C Z 692¹ 693 694¹ 695 A B C L N P Q R S (I) S (II) 696¹ 697¹ 698¹ 699¹
700–799	700–735¹ 737¹ 738¹ 739¹ 740¹ 742 743 744¹ 745 746–753¹ 755–799¹
800–899	800¹ 801¹ 802 803¹ 804¹ 805¹ 807 808–816¹ 818¹ 819¹ 820¹ 821¹ 822¹ 824–831¹ 832 833¹ 834 835–845¹ 847–899¹
900–999	900–951¹ 952 853¹ 854¹ 855¹ 956 957–967¹
¹ Unknown or not assigned