General Electric YF120

The General Electric YF120 was a turbofan engine with an afterburner that was specially developed in the 1980s for the "Advanced Tactical Fighter" program , from which the F-22 Raptor later emerged. However, after the YF119 was selected for series production by Pratt & Whitney in 1991 , development of the YF120 was discontinued. Later it was further developed in cooperation with Rolls-Royce for the JSF program to the F136 engine , although this also did not go into series production, as well as as the technological basis for the "Advanced Technology Engine Gas Generator" (ATEGG) and the " Joint Technology Demonstration Engine ”(JTDE) program.

The special technical feature of the YF120 was the variable bypass ratio ( variable cycle engine ). Generals Electric developed this technology especially for the requirements in the area of super cruises , i.e. flying in the supersonic range without afterburner. In the supersonic range or at high altitudes, the bypass flow was reduced to almost zero, making the YF120 behave like a turbojet . In the subsonic range, on the other hand, the secondary flow was increased again in order to reduce the specific fuel consumption. Although better flight performance could be achieved with the help of the variable secondary flow during the ATF test, the technology represented an increased development risk, which, together with the higher weight, was probably the main reason why the YF120 lost the ATF tender.

Technical specifications

• Length: 4.24 m
• Diameter: 1,067 mm
• Weight: 1,860 kg
• maximum thrust: 156.76 kN (with afterburner)
• Thrust-to-weight ratio: 8.59: 1

Web links

• GE / Allison / Rolls-Royce team Developing YF120 Fighter Engine for JSF Aircraft Candidates (English)