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 was brought into the project, at an early stage, to design, develop and manufacture an air-cooled high-pressure 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.

Design and development

Production started in 1992 with the thrust FJ44-1A, which comprises a diameter single stage blisk fan plus a single intermediate pressure booster stage, driven by a 2 stage low pressure turbine, supercharging a single stage centrifugal high pressure compressor, driven by a single stage uncooled high pressure 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 thrust at SLS, ISA is understood to be 0.456 lb/. A derated version, the thrust FJ44-1C has an SFC of.
An uprated version, the thrust FJ44-2A, was introduced in 1997. It has a larger 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. The thrust FJ44-2C is similar to the -2A, but incorporates an integrated hydromechanical fuel control unit.
Further updates include the 2004 introduction of the thrust FJ44-3A, which is similar to the -2A, but features an increased diameter fan and dual channel FADEC unit. The thrust FJ44-3A-24 is a derated version of the -3A.
In 2005, a new low end version, the FJ44-1AP, was introduced, with a 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.
Released in 2007 was the new thrust FJ44-4, which has a hi-tech fan of larger diameter than the -3 unit. As of March 2010, this engine was only in use on the Cessna CJ4, and since 2018 also on the new Pilatus PC-24.

Variants

;FJ44-1A
;FJ44-1AP
;FJ44-1C
;FJ44-2A
;FJ44-2C
;FJ44-3A
;FJ44-3AP
;FJ44-4A
;FJ44-4M
;F129

Applications

VariantApplicationTypeDeliveries
FJ44-1Cessna CitationJet CJ1/CJ1+/M2Business Jet1993-
FJ44-1SAAB Sk60Jet Trainerre-engine
FJ44-2Beechcraft Premier 1ABusiness Jet2001-2012
FJ44-2Cessna CitationJet CJ2Business Jet2000-2005
FJ44-2Cessna Citation 501SPBusiness Jetre-engine
FJ44-2Cessna Citation 550Business Jetre-engine
FJ44-2Scaled Composites ProteusExperimental1998
FJ44-2Syberjet SJ30Business Jet2007-2009
FJ44-2Learjet 25Business Jetre-engine
FJ44-2Virgin Atlantic GlobalFlyerExperimental2005
FJ44-3Cessna CitationJet CJ2+/CJ3+Business Jet2004-
FJ44-3Cessna Citation 550Business Jetre-engine
FJ44-3Nextant 400XTiBusiness Jetre-engine
FJ44-4Cessna CitationJet CJ4Business Jet2010-
FJ44-4Hawker 400XPRBusiness Jetre-engine
FJ44-4Pilatus PC-24Business Jet2018-
not deliveredAero L-39NGJet Trainerunder development
not deliveredAlenia Aermacchi M-345Jet TrainerUnder development
not deliveredCessna 526 CitationJetJet Trainer2 prototypes
not deliveredEviation Jets EV-20 Vantage JetBusiness Jet1 prototype
not deliveredGrob G180 SPnBusiness Jet4 prototypes
not deliveredHawker 200Business JetCancelled
not deliveredLockheed Martin PolecatDroneCrashed
not deliveredLockheed Martin RQ-3 DarkStarDroneCancelled
not deliveredPiper PA-47 PiperJet/AltaireBusiness Jet1 prototype
not deliveredScaled Composites TriumphBusiness Jet1 prototype

Specification