The General Electric J79 is an axial-flow turbojet engine built for use in a variety
of fighter and bomber aircraft. The J79 was produced by General Electric Aircraft Engines
in the United States, and under license by several other companies worldwide
A simplified civilian 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 as a prototype for the US market.
Development The J79 was developed in the 1950s as an outgrowth
of the General Electric J73 engine program, originally called J73-GE-X24A, intended for
reliable Mach 2 performance. 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. The J79 was lowered
from the bomb bay and the four J47s were shut down leaving the B-45 flying on the single
J79. 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. The J79 was used on the F-104 Starfighter,
B-58 Hustler, F-4 Phantom II, A-5 Vigilante, and the IAI Kfir. It enjoyed a production
run of more than 30 years. Over 17,000 J79s were built in the United States, 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 offer better cruise fuel
efficiency by moving unburned 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 and the U.S. Air Force. Design
The J79 is a single-spool turbojet with a seventeen-stage compressor with a novel arrangement
of variable stator blades which allow the engine to develop pressure similar to a twin-spool
engine at a much lower weight. Each blade is made largely of stainless steel. Each blade
today costs several thousand dollars to replace. The compressor blades are mounted on disks
and spaced with corrosion-resistant steel spacers.
In the F-104 and the F-4, the J79 makes a particular howling sound at certain throttle
settings. The sound is thought to be due to airflow in the exhaust section of the engine
being disturbed by the engine bypass flaps. This strange feature led to the NASA operated
F-104B Starfighter, N819NA, being named Howling Howland. Early engines also produced noticeable
quantities of smoke, especially at mid-throttle/cruise settings, a disadvantage in a combat aircraft
making them easier to visually spot. 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 the powering of pipelines.
The J79 has two commercial derivatives: CJ805-3, and the CJ805-23 Most fitted to the Convair
CV-880 and the Convair CV-990. Variants and applications
XJ79-GE-1 Prototype. First ground static test run on
8 June 1954 produced 14,350 lbf with afterburner. YJ79-GE-1
Flight test engines were designated YJ79-GE-1. J79-GE-2
Powered the McDonnell F-4H-1 Phantom, 16,100 lbf 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-GE3A
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 with afterburner. J79-GE-5B
Convair B-58 Hustler 15,600 lbf with afterburner. 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 with
16,950 lbf 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 of afterburner thrust. J79-GE-11A
F-104G and TF-104G. 15,600 lbf 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.
J79-GE-17 F-4E, 17,900 lbf 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. with 18,750 lbf afterburning thrust
for the IAI Kfir. Applications
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
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
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.
Data from General characteristics
Type: Afterburning turbojet engine Length: 17.4 ft
Diameter: 3.2 ft Dry weight: 3,850 lb
Components Compressor: 17-stage axial compressor with
variable stator vanes Combustors: cannular
Turbine: 3-stage Performance
Maximum thrust: 11,905 lbf dry; 17,835 lbf with afterburner
Overall pressure ratio: 13.5:1 Air mass flow: 170 lb/s
Turbine inlet temperature: 1,710 °F Specific fuel consumption: 1.965 lb/(h·lbf))
with afterburner, 0.85 lb/(h·lbf)) at military thrust
Thrust-to-weight ratio: 4.6:1 See also
North American Eagle United States military aero engine designations
Related development General Electric CJ805
General Electric YJ93 General Electric LM1500
Related lists List of aircraft engines
References Notes
Bibliography
Williams, Nick and Steve Ginter "Douglas F4D Skyray". Simi Valley, California: Ginter,
1986. ISBN 0-942612-13-2. External links
General Electric Aviation, J79 page GE: The History of Aircraft Engines
Animation of J79 turbojet