Type Turbojet
National origin United States
Manufacturer General Electric Aircraft Engines
Major applications Northrop YF-17
Developed into General Electric F404

The General Electric YJ101 was an afterburning turbojet engine, as signified by its "J" designation, in the 15,000 lbf class. It was designed for the Northrop P-530 Cobra[1] but its initial application was the Northrop YF-17 entry in the Lightweight Fighter (LWF) competition. It was subsequently developed into the widely used General Electric F404.


Two essential requirements for the engine were reliability, which can be measured by the number of times a particular engine model has to be shutdown during flight (in-flight shut-down rate), and handling, which means stall-free operation throughout the flight envelope together with allowing the pilot to make unrestricted throttle movements anywhere between idle and maximum afterburner.[2]

The engine used continuous bypass bleed from the compressor to cool the afterburner liner and nozzle. The bypass air was not mixed with hot air from the turbine[3] as the afterburner was a simple turbojet style with no requirement for intentional mixing of the bypass flow with the turbine exhaust.[4] However, mixing is an important requirement for turbofan engines.

General Electric chose to describe the engine differently depending on circumstance. To emphasize simplicity it was a "leaky turbojet". For advanced technology it was "the world's first self-cooled turbojet".[5] This referred to using the compressor bypass air to cool the afterburner instead of using much hotter turbine exhaust gas.


Specifications (YJ101)

Data from Jane's All The World's Aircraft 1975-76 [6]

General characteristics



See also

Related development

Related lists


  1. ^ Jane's All The World's Aircraft 1975-76, ISBN 0 531 03250 7 p.747
  2. ^ Flight International, 14 April 1984, F404: Fighter pilot's engine, p.1021
  3. ^ Flight International, 21 August 1978, "F-18: US Navy Air Combat Fighter", p.262
  4. ^ Patierno, J. (1974). "YF-17 design concepts". 6th Aircraft Design,Flight Test and Operations Meeting. American Institute of Aeronautics and Astronautics. doi:10.2514/6.1974-936.
  5. ^ The Lightweight Fighter Program:A Successful Approach to Fighter Technology Transition, Aronstein and Piccirillo 1996, ISBN 1 56347 193 0, p.42
  6. ^ Jane's All The World's Aircraft 1975-76, ISBN 0 531 03250 7 p.748