The Williams FJ44 is a family of small, two-spool, turbofan engines produced by Williams International for the light business jet market. Until the recent boom in the very light jet market, the FJ44 was one of the smallest turbofans available for civilian applications. Although a Williams design, Rolls-Royce was brought into the project at an early stage to design, develop, and manufacture an air-cooled high-pressure (HP) turbine for the engine. The FJ44 first flew on July 12, 1988 on the Scaled Composites/Beechcraft Triumph aircraft.

The Williams FJ33 is a newer, smaller engine based on the basic FJ44 design.

Development Production started in 1992 with the thrust FJ44-1A. The FJ44-1C is derated to . The uprated to FJ44-2A was introduced in 1997. The thrust FJ44-3A was introduced in 2004. In 2005, a new low end version, the FJ44-1AP, was introduced, with a takeoff thrust. Released in 2007 was the new thrust FJ44-4. In 2010 this engine was in use on the Cessna CJ4, and since 2018 also on the new Pilatus PC-24.

Design

The FJ44-1A has a single stage blisk fan plus a single intermediate pressure (IP) booster stage, both driven by a 2 stage low pressure (LP) turbine, and supercharging a single stage centrifugal high pressure (HP) compressor, driven by a single stage uncooled high pressure (HP) turbine. The combustor is an impingement cooled annular design. Fuel is delivered to the combustor through an unusual rotating fuel nozzle system, rather than the standard fuel-air mixers or vapourisers. The bypass duct runs the full length of the engine. The FJ44-2A has two additional booster compressor stages.

Variants FJ44-1A thrust, production started in 1992, diameter fan, SFC at full thrust at SLS, ISA is understood to be 0.456 lb/(hr lbf), FJ44-1AP takeoff thrust, introduced in 2005, 5% better specific fuel consumption, lower internal temperatures, similar to the -1A with a higher pressure ratio fan, a new combustor and LP turbine, a new full length bypass duct/exhaust mixer and a dual channel FADEC.FJ44-1AP at www.williams-int.com, Accessed 2006-05-07 FJ44-1C thrust, derated version of the FJ44-1A, SFC of .FJ44-1 at www.williams-int.com, Accessed 2006-05-07FJ44 for military trainer aircraft at defence.rolls-royce.com , Accessed 2006-05-07 FJ44-2A thrust, introduced in 1997, larger diameter fan, with two additional booster stages to increase core flow, centrifugal compressor throttled-back aerodynamically to a lower HPC pressure ratio than the -1, exhaust mixer and a fuel electronic control unit.FJ44-2 at www.williams-int.com, Accessed 2006-05-07 FJ44-2C thrust, similar to the -2A with an integrated hydromechanical fuel control unit. FJ44-3A thrust, 2004 introduction, similar to the -2A with a larger fan and dual channel FADEC unit.FJ44-3 at www.williams-int.com, Accessed 2006-05-07 FJ44-3A-24 thrust, derated -3A. FJ44-3AP thrust.Williams Fanjet Family , Accessed 2020-02-20 FJ44-4A thrust, released in 2007, hi-tech fan of larger diameter than the -3 unit.FJ44-4 at www.williams-int.com, Accessed 2010-03-12 Used on the Cessna CJ4 and the Pilatus PC-24. FJ44-4C 3,450 lbf (15.3kN) thrust. Used on the upcoming Honda HA-480 Echelon. FJ44-4M Williams-Rolls F129 Military designation for the derated FJ44-1C with thrust.

Applications

Variant Application Type Deliveries FJ44-1 Cessna CitationJet CJ1/CJ1+/M2 Business jet 1993- SAAB Sk60 Jet trainer re-engine FJ44-2 Beechcraft Premier 1A Business jet 2001-2012 Cessna CitationJet CJ2 Business jet 2000-2005 Cessna Citation 501SP Business jet re-engine Cessna Citation 550 Business jet re-engine Scaled Composites Proteus Experimental 1998 Syberjet SJ30 Business jet 2007-2009 Learjet 25 Business jet re-engine Virgin Atlantic GlobalFlyer Experimental 2005 FJ44-3 Cessna CitationJet CJ2+/CJ3+ Business jet 2004- Cessna Citation 550 Business jet re-engine Nextant 400XTi Business jet re-engine FJ44-4 Cessna CitationJet CJ4 Business jet 2010- Hawker 400XPR Business jet re-engine Pilatus PC-24 Business jet 2018- Boeing MQ-28 Ghost Bat UCAV 2021- FJ44-4M Aero L-39 Skyfox Jet trainerLight attack aircraft 2022- Anduril YFQ-44UCAV2025- FJ44-4M-34 Alenia Aermacchi M-345 Jet trainer 2018- not delivered Cessna 526 CitationJet Jet trainer 2 prototypes Eviation Jets EV-20 Vantage Jet Business jet 1 prototype Grob G180 SPn Business jet 4 prototypes Hawker 200 Business jet Cancelled Lockheed Martin Polecat Drone Crashed Lockheed Martin RQ-3 DarkStar Drone Cancelled Piper PA-47 PiperJet/Altaire Business jet 1 prototype Scaled Composites Triumph Business jet 1 prototype

Specifications + Type Certificate Data Sheet Variant FJ44-1AP FJ44-2 FJ44-3 FJ44-4 Configuration Twin-spool turbofan with 1-stage fan and annular combustor LP compressor 1-stage axial 3-stage axial HP compressor 1-stage centrifugalTurbine 1-stage HP, 2-stage LPThrust Weight T/W ratio4.13–4.574.42–4.535.81–5.615.47 Length Diameter

See also

References

Notes

External links

Williams International product page