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Williams FJX-1 et FJX-2

In 1996, Williams teamed with NASA to develop a smaller and lighte turbofan engine ”the FJX-2” for general aviation. The General Aviation Propulsion (GAP) program is part of NASA's Advanced General Aviation Transport Experiments (AGATE) program a joint NASA/industry venture to revitalize general aviation. AGATE was born at the 1992 Oshkosh convention.

The FJX-2 is a high-bypass-ratio turbofan engine that produces 700 pounds of thrust, yet weighs only 85-100 pounds, about one-fourth the weight of piston engine propulsion systems with similar capabilities. To keep costs low, the FJX-2 team applied many lessons learned from research of automotive gas turbine engines. Emphasis was placed on simplifying design and reducing the number of parts. Low-cost design techniques and advanced automated manufacturing methods have led to the first turbine engine that is cost competitive with piston engines. While not as fuel efficient as today's comparable piston-powered aircraft, new turbofan jets will have equivalent or lower takeoff-to-landing fuel consumption.

The first FJX-2 turbofan engine was fully assembled on December 18, 1998, by Williams International in Walled Lake, Michigan, marking a major milestone in the GAP program. On December 22, 1998, the first operational test of the new FJX-2 engine was conducted in the Williams static test facility. The engine was then disassembled for inspection and found to be in excellent condition.

FJX2 technical data

Initial testing1998
TypeTwo-shaft turbofan
Nb. built


Diameter368 mm14.5 in.
Lenth1041 mm41 in.


Not equipped39 kg86 lb


Max RPMt/mn rpm
Max continuous t/mnrpm
Max Idle t/mnrpm
Thrust at max3114 N700 lb
Thrust at max continuouskglb
Thrust at idle
Pressure ratio at max / 1
Max flowkg/slb/s
Max continue EGT deg.Cdef.F


Fuel Consumptionkg/hlb/h
Specific fuel consumptionkg/N/hlb/lb/hr)