Williams FJ44

The Williams FJ44 is a family of small, two-spool, turbofan engines produced by Williams International/Rolls-Royce 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 basically a Williams design, Rolls-Royce were brought into the project, at an early stage, to design, develop and manufacture an air-cooled HP turbine for the engine.

The FJ44 first flew on July 12, 1988 on the Scaled Composites/Beechcraft Triumph aircraft.

Engine Family

Production started in 1992 with the 1900 lbf (2.58 kN) thrust FJ44-1A, which comprises a 20.9 in (531 mm) diameter single stage blisk fan plus a single intermediate pressure (IP) booster stage, driven by a 2 stage low pressure (LP) turbine, 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 the engine. Specific fuel consumption at 1900 lbf (2.58 kN) thrust at SLS, ISA is understood to be 0.456lb/hr/lbf. A derated version, the 1500 lbf (2.03 kN) thrust FJ44-1C has an SFC of 0.460lb/hr/lbf. [ [http://www.williams-int.com/high/product/engines/fj44-1.htm FJ44-1] at [http://www.williams-int.com www.williams-int.com] , Accessed 2006-05-07] [ [http://defence.rolls-royce.com/FJ44-gas-turbines-for-trainer-aircraft/ FJ44 for military trainer aircraft] at [http://defence.rolls-royce.com defence.rolls-royce.com] , Accessed 2006-05-07]

An uprated version, the convert|2300|lbf|abbr=on thrust FJ44-2A, was introduced in 1997. It has a larger 21.7 in (551 mm) diameter fan, with two additional booster stages to increase core flow. Owing to stressing considerations, the centrifugal compressor is throttled-back aerodynamically to a lower HPC pressure ratio than the -1. Other features include an exhaust mixer and an electronic fuel control unit. [ [http://www.williamsint.com/high/product/engines/fj44-2.htm FJ44-2] at [http://www.williams-int.com www.williams-int.com] , Accessed 2006-05-07] The 2400 lbf (3.25 kN) thrust FJ44-2C is similar to the -2A, but incorporates an integrated hydromechanical fuel control unit.

Further uprates include the 2004 introduction of the 2820 lbf (3.82 kN) thrust FJ44-3A, which is similar to the -2A, but features an increased diameter fan and dual channel FADEC (Full Authority Digital Engine Control) unit. [ [http://www.williams-int.com/high/product/engines/fj44-3.htm FJ44-3] at [http://www.williams-int.com www.williams-int.com] , Accessed 2006-05-07] The 2490 lbf (3.38 kN) thrust FJ44-3A-24 is a derated version of the -3A.

In development (as of early 2006) is the 3500 lbf (4.75 kN) thrust FJ44-4, which has a hi-tech fan of larger diameter than the -3 unit. [ [http://www.williams-int.com/high/product/engines/fj44-4.htm FJ44-4] at [http://www.williams-int.com www.williams-int.com] , Accessed 2006-05-07]

In 2005, a new low end version, the FJ44-1AP, was introduced, with a 1965 lbf (2.66 kN) takeoff thrust, 5% better specific fuel consumption, and lower internal temperatures. The -1AP is similar to the -1A, except for a higher pressure ratio fan, a new combustor and LP turbine, a new full length bypass duct/exhaust mixer and a dual channel FADEC. [ [http://www.williams-int.com/high/product/engines/fj44-1ap.htm FJ44-1AP] at [http://www.williams-int.com www.williams-int.com] , Accessed 2006-05-07]

In addition to these FJ44 family variants, the Williams FJ33, first certified in 2004, is a smaller engine based on the FJ44 basic design.

Applications

The following aircraft use FJ44 model engines: [ [http://www.williams-int.com/high/product/Airplanes/Airplanes.htm Airplanes using FJ series engines] at [http://www.williams-int.com www.williams-int.com] , Accessed 2006-05-07]
* FJ44-1
** Scaled Composites/Beechraft Triumph (First flight of an FJ44)
** Cessna CJ1
** Cessna CJ1+
** Eviation EV-20 Vantage Jet
** Saab 105
* FJ44-2
** Cessna CJ2
** Raytheon Premier I
** Scaled Composites Proteus
** Citation FJ44 Eagle
** Sierra Stallion
** Sino Swearingen SJ30-2
** SpiritWing (Learjet 25 modification)
** Virgin Atlantic GlobalFlyer
* FJ44-3
** Cessna CJ2+
** Cessna CJ3
** Grob SPn Utility Jet
** Lockheed Martin Polecat
** PiperJet
** Sierra Super II / Sierra Super SII

References