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FJ44
A Williams FJ44-3ATW turbofan engine
Type	Turbofan
National origin	United States
Manufacturer	Williams International
First run	1985[1]
Major applications	Beechcraft Premier I Cessna CitationJet Piper PiperJet Altaire Saab 105 Grob G180 SPn Pilatus PC-24
Developed into	Williams FJ33

TheWilliams FJ44 is a family of small, two-spool,turbofan engines produced byWilliams International for thelight business jet market. Until the recent boom in thevery 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 theScaled Composites/Beechcraft Triumph aircraft.

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

Production started in 1992 with the 1,900 lbf (8.5 kN) thrustFJ44-1A. TheFJ44-1C is derated to 1,500 lbf (6.7 kN).The uprated to 2,300 lbf (10 kN)FJ44-2A was introduced in 1997.The 2,820 lbf (12.5 kN) thrustFJ44-3A was introduced in 2004.In 2005, a new low end version, theFJ44-1AP, was introduced, with a 1,965 lbf (8.74 kN) takeoff thrust.Released in 2007 was the new 3,600 lbf (16 kN) thrustFJ44-4. In 2010 this engine was in use on theCessna CJ4, and since 2018 also on the newPilatus PC-24.

The FJ44-1A has a single stageblisk 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.

FJ44-1A

1,900 lbf (8.5 kN) thrust, production started in 1992, 20.9 in (530 mm) diameter fan,SFC at full thrust at SLS, ISA is understood to be 0.456 lb/(hr lbf),

FJ44-1AP

1,965 lbf (8.74 kN) 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 channelFADEC.^[2]

FJ44-1C

1,500 lbf (6.7 kN) thrust, derated version of the FJ44-1A, SFC of 0.460 lb/lbf/h (46.9 kg/kN/h).^[3][4]

FJ44-2A

2,300 lbf (10 kN) thrust, introduced in 1997, larger 21.7 in (550 mm) 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 fuelelectronic control unit.^[5]

FJ44-2C

2,400 lbf (11 kN) thrust, similar to the -2A with an integrated hydromechanical fuel control unit.

FJ44-3A

2,820 lbf (12.5 kN) thrust, 2004 introduction, similar to the -2A with a larger fan and dual channelFADEC unit.^[6]

FJ44-3A-24

2,490 lbf (11.1 kN) thrust, derated -3A.

FJ44-3AP

3,000 lbf (13 kN) thrust.^[7]

FJ44-4A

3,600 lbf (16 kN) thrust, released in 2007, hi-tech fan of larger diameter than the -3 unit.^[8] Used on theCessna CJ4 and thePilatus PC-24.

FJ44-4C

3,450 lbf (15.3kN) thrust. Used on the upcoming Honda HA-480 Echelon.^[9][10]

FJ44-4M

Williams-Rolls F129

Military designation for the derated FJ44-1C with 1,500 lbf (6.7 kN) thrust.

Related development

• Williams FJ33

Related lists

• List of aircraft engines

Wikimedia Commons has media related toWilliams FJ44.

• Williams International product page

• Medium-bypass turbofan engines
• 1980s turbofan engines
• Williams aircraft engines
• Centrifugal-flow turbojet engines

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