View source for Williams FJ44

{{short description|Small turbofan engine}}
{{primary|date=November 2021}}
<!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. -->
{|{{Infobox aircraft begin
 |name= FJ44
 |image=Williams FJ44-3ATW.jpg
 |caption=A Williams FJ44-3ATW turbofan engine 
}}
{{Infobox aircraft engine
 |type= [[Turbofan]]
 |national origin= [[United States]]
 |manufacturer= [[Williams International]]
 |first run= 1985<ref name="FlightGlobal Archives">{{cite news |url= https://www.flightglobal.com/pdfarchive/view/1985/1985%20-%202808.html?search=FJ44|title= Williams Imagines Future Concept |work= Flight International |date= 12 October 1985 |access-date=6 April 2017}}</ref>
 |major applications= [[Beechcraft Premier I]] <br> [[Cessna CitationJet]] <br> [[Piper PiperJet Altaire]] <br> [[Saab 105]] <br> [[Grob G180 SPn]] <br> [[Pilatus PC-24]]  
 |number built =  
 |program cost = 
 |unit cost = 
 |developed from =  
 |developed into = [[Williams FJ33]] 
 |variants with their own articles = 
}}
|}

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 Triumph|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 {{Convert|1900|lbf|kN|abbr=on|lk=on}} thrust '''FJ44-1A'''. The '''FJ44-1C''' is derated to {{Convert|1500|lbf|kN|abbr=on}}.
The uprated to {{Convert|2300|lbf|kN|abbr=on}} '''FJ44-2A''' was introduced in 1997.
The {{Convert|2820|lbf|kN|abbr=on}} thrust '''FJ44-3A''' was introduced in 2004.
In 2005, a new low end version, the '''FJ44-1AP''', was introduced, with a {{Convert|1965|lbf|kN|abbr=on}} takeoff thrust.
Released in 2007 was the new {{Convert|3600|lbf|kN|abbr=on}} thrust '''FJ44-4'''. In 2010 this engine was in use on the [[Cessna CitationJet#Model 525C|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
: {{Convert|1900|lbf|kN|abbr=on|lk=on}} thrust, production started in 1992, {{Convert|20.9|in|mm|abbr=on}} diameter fan, [[Specific fuel consumption (thrust)|SFC]] at full thrust at SLS, ISA is understood to be 0.456&nbsp;lb/(hr lbf), 
;FJ44-1AP
: {{Convert|1965|lbf|kN|abbr=on}} 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]].<ref>[http://www.williams-int.com/high/product/engines/fj44-1ap.htm FJ44-1AP] {{Webarchive|url=https://web.archive.org/web/20060505044353/http://www.williams-int.com/high/product/engines/fj44-1ap.htm |date=2006-05-05 }} at [http://www.williams-int.com www.williams-int.com], Accessed 2006-05-07</ref>
;FJ44-1C
: {{Convert|1500|lbf|kN|abbr=on}} thrust, derated version of the FJ44-1A, SFC of {{Convert|0.460|lb/lbf/h|kg/kN/h|abbr=on}}.<ref>[http://www.williams-int.com/high/product/engines/fj44-1.htm FJ44-1] {{Webarchive|url=https://web.archive.org/web/20060505044413/http://www.williams-int.com/high/product/engines/fj44-1.htm |date=2006-05-05 }} at [http://www.williams-int.com www.williams-int.com], Accessed 2006-05-07</ref><ref>[http://defence.rolls-royce.com/FJ44-gas-turbines-for-trainer-aircraft/ FJ44 for military trainer aircraft] {{Webarchive|url=https://web.archive.org/web/20070311031549/http://defence.rolls-royce.com/FJ44-gas-turbines-for-trainer-aircraft/ |date=2007-03-11 }} at [http://defence.rolls-royce.com defence.rolls-royce.com] {{Webarchive|url=https://web.archive.org/web/20060428182356/http://defence.rolls-royce.com/ |date=2006-04-28 }}, Accessed 2006-05-07</ref>
;FJ44-2A
: {{Convert|2300|lbf|kN|abbr=on}} thrust, introduced in 1997, larger {{Convert|21.7|in|mm|abbr=on}} 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]].<ref>[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</ref>
;FJ44-2C
: {{Convert|2400|lbf|kN|abbr=on}} thrust, similar to the -2A with an integrated hydromechanical fuel control unit.
;FJ44-3A
: {{Convert|2820|lbf|kN|abbr=on}} thrust, 2004 introduction, similar to the -2A with a larger fan and dual channel [[Full Authority Digital Engine Control|FADEC]] unit.<ref>[http://www.williams-int.com/high/product/engines/fj44-3.htm FJ44-3] {{Webarchive|url=https://web.archive.org/web/20060505044406/http://www.williams-int.com/high/product/engines/fj44-3.htm |date=2006-05-05 }} at [http://www.williams-int.com www.williams-int.com], Accessed 2006-05-07</ref>
; FJ44-3A-24
: {{Convert|2490|lbf|kN|abbr=on}} thrust, derated -3A.
;FJ44-3AP
: {{Convert|3000|lbf|kN|abbr=on}} thrust.<ref>[http://www.williams-int.com/uploads/Williams%20Fanjet%20Family.pdf Williams Fanjet Family], Accessed 2020-02-20</ref>
;FJ44-4A
: {{Convert|3600|lbf|kN|abbr=on}} thrust, released in 2007, hi-tech fan of larger diameter than the -3 unit.<ref>[http://www.williams-int.com/information.html?pid=1 FJ44-4] {{Webarchive|url=https://web.archive.org/web/20100412043319/http://www.williams-int.com/information.html?pid=1 |date=2010-04-12 }} at [http://www.williams-int.com www.williams-int.com], Accessed 2010-03-12</ref> Used on the [[Cessna CitationJet#Model 525C|Cessna CJ4]] and the [[Pilatus PC-24]]. 
;FJ44-4C
:3,450 lbf (15.3kN) thrust. Used on the upcoming Honda HA-480 Echelon.<ref>{{Cite web |title=plane announcement |url=https://www.aopa.org/news-and-media/all-news/2023/october/16/honda-goes-for-the-upper-echelon}}</ref><ref>{{Cite web |title=honda specs |url=https://www.hondajet.com/-/media/HondaJet/Photos/HondaJet-Echelon/HondaJet_Echelon_Digital_Brochure_FINAL.pdf}}</ref>
;FJ44-4M
;Williams-Rolls F129
:Military designation for the derated FJ44-1C with {{Convert|1500|lbf|kN|abbr=on}} thrust.

==Applications==
[[File:OO-FLN.JPG|thumb|2,000 [[CitationJet]]s have been delivered by June 2017<ref name=8jun2017PR>{{cite press release |url= http://txtav.com/en/newsroom/2017/06/textron-aviation-celebrates-light-jet-leadership-with-2000th-delivery-for-cessna-cj-family |title= Textron Aviation celebrates light jet leadership with 2,000th delivery for Cessna CJ family |date= June 8, 2017 |publisher= Textron Aviation}}</ref>

]]
{| class="wikitable sortable"
|-
! Variant !! Application !! Type !! Deliveries
|-
| rowspan=2 | FJ44-1<ref>{{cite web |url= http://www.williams-int.com/products/airplanes-with-the-fj44-1-engine |title= Airplanes with the FJ44-1 Engine |publisher= Williams International |access-date= 2019-03-05 |archive-date= 2019-03-01 |archive-url= https://web.archive.org/web/20190301222118/http://www.williams-int.com/products/airplanes-with-the-fj44-1-engine |url-status= dead }}</ref>
| [[Cessna CitationJet]] CJ1/CJ1+/M2 || Business jet || 1993-
|-
| [[SAAB Sk60]] || Jet trainer || re-engine
|-
| rowspan=8 | FJ44-2<ref>{{cite web |url= http://www.williams-int.com/products/airplanes-with-the-fj44-2-engine |title= Airplanes with the FJ44-2 Engine |publisher= Williams International |access-date= 2019-03-05 |archive-date= 2019-03-10 |archive-url= https://web.archive.org/web/20190310115133/http://www.williams-int.com/products/airplanes-with-the-fj44-2-engine |url-status= dead }}</ref>
| [[Beechcraft Premier]] 1A	|| Business jet || 2001-2012
|-
| [[Cessna CitationJet]] CJ2 || Business jet || 2000-2005
|-
| [[Cessna Citation 501]]SP || Business jet || re-engine{{efn|Sierra Industries FJ44 Stallion}}
|-
| [[Cessna Citation 550]] || Business jet || re-engine{{efn|Sierra Industries FJ44 Eagle II}}
|-
| [[Scaled Composites Proteus]]	|| Experimental || 1998
|-
| [[Syberjet SJ30]] || Business jet || 2007-2009
|-
| [[Learjet 25]] || Business jet || re-engine{{efn|SpiritWing}} 
|-
| [[Virgin Atlantic GlobalFlyer]] || Experimental || 2005
|-
| rowspan=3 | FJ44-3<ref>{{cite web |url= http://www.williams-int.com/products/airplanes-with-the-fj44-3-engine |title= Airplanes with the FJ44-3 Engine |publisher= Williams International |access-date= 2019-03-05 |archive-date= 2019-03-01 |archive-url= https://web.archive.org/web/20190301221747/http://www.williams-int.com/products/airplanes-with-the-fj44-3-engine |url-status= dead }}</ref>
| [[Cessna CitationJet]] CJ2+/CJ3+ || Business jet || 2004-
|-
| [[Cessna Citation 550]] || Business jet || re-engine{{efn|Sierra Industries Super II/S-II}}
|-
| [[Nextant 400XT]]i || Business jet || re-engine
|-
| rowspan=3 | FJ44-4<ref>{{cite web |url= http://www.williams-int.com/products/airplanes-with-the-fj44-4-engine |title= Airplanes with the FJ44-4 Engine |publisher= Williams International |access-date= 2019-03-05 |archive-date= 2019-02-23 |archive-url= https://web.archive.org/web/20190223173817/http://www.williams-int.com/products/airplanes-with-the-fj44-4-engine |url-status= dead }}</ref>
| [[Cessna CitationJet]] CJ4  || Business jet || 2010-
|-
| [[Hawker 400XPR]] || Business jet || re-engine
|-
| [[Pilatus PC-24]] || Business jet || 2018-
|-
| rowspan=1 | FJ44-4M 
| [[Aero L-39 Skyfox]] || Jet trainer<br>Light attack aircraft || 2022- 
|-
| rowspan=1 | FJ44-4M-34
| [[Alenia Aermacchi M-345]] || Jet trainer || 2018-
|-
| rowspan=8 | not delivered{{clarify|date=August 2019}}
| [[Cessna 526 CitationJet]]{{efn|as Williams-Rolls F129|name=|group=}}|| 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==
{| class="wikitable" style="text-align:center"
|+ Type Certificate Data Sheet<ref>{{cite web |url= https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/60398924b8e6df678625831d0047e4be/$FILE/E3GL_Rev_22.pdf |title= Type Certificate Data Sheet NO. E3GL |date= October 4, 2018 |publisher= FAA}}</ref>
! Variant
! FJ44-1AP<ref>{{cite news |url= http://www.williams-int.com/products/fj44-1ap |title= FJ44-1AP |publisher= Williams International |access-date= 2019-03-05 |archive-date= 2019-03-10 |archive-url= https://web.archive.org/web/20190310120543/http://www.williams-int.com/products/fj44-1ap |url-status= dead }}</ref>
! FJ44-2<ref>{{cite news |url= http://www.williams-int.com/products/fj44-2 |title= FJ44-2 |publisher= Williams International |access-date= 2019-03-05 |archive-date= 2019-02-22 |archive-url= https://web.archive.org/web/20190222142724/http://www.williams-int.com/products/fj44-2 |url-status= dead }}</ref>
! FJ44-3<ref>{{cite news |url= http://www.williams-int.com/products/fj44-3 |title= FJ44-3 |publisher= Williams International |access-date= 2019-03-05 |archive-date= 2019-02-23 |archive-url= https://web.archive.org/web/20190223174323/http://www.williams-int.com/products/fj44-3 |url-status= dead }}</ref>
! FJ44-4<ref>{{cite news |url= http://www.williams-int.com/products/fj44-4 |title= FJ44-4 |publisher= Williams International |access-date= 2019-03-05 |archive-date= 2019-03-10 |archive-url= https://web.archive.org/web/20190310034011/http://www.williams-int.com/products/fj44-4 |url-status= dead }}</ref>
|-
| Configuration || colspan=4 | Twin-spool turbofan with 1-stage fan and [[annular combustor]]
|- 
| LP compressor || 1-stage [[Axial compressor|axial]]|| colspan="3" | 3-stage axial
|-
| HP compressor || colspan=4 | 1-stage [[Centrifugal compressor|centrifugal]]
|-
|[[Turbine]]|| colspan="4" | 1-stage HP, 2-stage LP
|-
|[[Thrust]]
| {{cvt|1,900-2,100|lbf|kN|abbr=}}
| {{cvt|2,300-2,400|lbf|kN|1}}
| {{cvt|3,000|lbf|kN|1}}
| {{cvt|3,600|lbf|kN|1}}
|-
| Weight
| {{cvt|460|lb|0|abbr=}}
| {{cvt|520-530|lb|0}}
| {{cvt|516-535|lb}}
| {{cvt|658|lb|0}}
|-
| Length
| {{cvt|41.4|in|cm|abbr=}}
| {{cvt|47.2|in|cm}}
| {{cvt|48.0|in|cm}}
| {{cvt|52.8|in|cm}}
|-
| Diameter
| {{cvt|20.7|in|cm}}
| {{cvt|21.8|in|cm}}
| {{cvt|23.0|in|cm}}
| {{cvt|25.3|in|cm}}
|}

==See also==
{{Aircontent
|see also=
|related=
* [[Williams FJ33]]
|similar engines=
|lists=
* [[List of aircraft engines]]
}}

==References==
{{reflist}}

==Notes==
{{notelist}}

==External links==
{{Commons category}}
* [http://www.williams-int.com/products Williams International product page]

{{Williams aeroengines}}
{{US military gas turbine aeroengines}}
{{Swedish military gas turbine aeroengines}}

[[Category:Medium-bypass turbofan engines]]
[[Category:1980s turbofan engines]]
[[Category:Williams aircraft engines|FJ44]]
[[Category:Centrifugal-flow turbojet engines]]