The Williams FJ44 is a family of small, two-spool,

turbofan The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the ''turbo'' portion refers to a gas turbine engine which ac ...

engines produced by

Williams International Williams International is an American manufacturer of small gas turbine engines based in Pontiac, Michigan, United States. It produces jet engines for cruise missiles and small jet aircraft. History Dr. Sam B. Williams worked at Chrysler on th ...

for the light business jet market. Until the recent boom in the

very light jet A very light jet (VLJ), entry-level jet or personal jet, previously known as a microjet, is a category of small business jets seating four to eight people. VLJs are considered the lightest business jets and are approved for single-pilot operati ...

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 (HP) turbine for the engine. The FJ44 first flew on July 12, 1988 on the Scaled Composites/Beechcraft Triumph aircraft. The

Williams FJ33 The Williams FJ33 is an American family of turbofan jet engines intended for use in very light jet aircraft. The FJ33 is a scaled-down version of the FJ44 engine. The FJ33-5A is the latest version certified in June 2016. Design Engine configur ...

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 The Pilatus PC-24 is a light business jet produced by Pilatus Aircraft of Switzerland. Following the success of the PC-12 single engine turboprop, work on the twin engine jet began in 2007 for greater range and speed, keeping the rugged airf ...

Design

The FJ44-1A has a single stage

blisk A blisk (portmanteau of bladed disk) is a turbomachine component comprising both rotor disk and blades. It serves as a critical component of the engine compressor to allow a sufficient quantity of compressed air to enter the engine for combustion ...

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. ;FJ44-1C : thrust, derated version of the FJ44-1A, SFC of . ;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 In aviation, exhaust mixer is a feature of many turbofan engines, where the bypass (cold/slow) air is mixed with the core (hot/fast) exhaust gases, before exhausting to atmospheric pressure through a common (mixed flow) propelling nozzle. Benef ...

and a fuel

electronic control unit An electronic control unit (ECU), also known as an electronic control module (ECM), is an embedded system in automotive electronics that controls one or more of the electrical systems or subsystems in a car or other motor vehicle. Modern vehic ...

. ;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. ; FJ44-3A-24 : thrust, derated -3A. ;FJ44-3AP : thrust. ;FJ44-4A : thrust, released in 2007, hi-tech fan of larger diameter than the -3 unit.FJ44-4
a
www.williams-int.com
Accessed 2010-03-12 Used on the Cessna CJ4 and the

. ;FJ44-4M ;Williams-Rolls F129 :Military designation for the derated FJ44-1C with 1500lbf (6.672kN) power output.

Applications

Specification

References

External links

Williams International product page
{{Swedish military gas turbine aeroengines Medium-bypass turbofan engines 1980s turbofan engines FJ44 Centrifugal-flow turbojet engines