Editing Wingtip device (section)

===Implementations===

[[File:Learjet 28-29.jpg|thumb|A [[Learjet 28/29]], the first commercial aircraft with winglets]]

Learjet exhibited the prototype [[Learjet 28]] at the 1977 [[National Business Aviation Association]] convention. It employed the first winglets ever used on a production aircraft, either civilian or military. Learjet developed the winglet design without NASA assistance. Although the Model 28 was intended to be a prototype experimental aircraft, performance was such that it resulted in a production commitment from Learjet. Flight tests showed that the winglets increased range by about 6.5 percent and improved directional stability. Learjet's application of winglets to production aircraft continued with newer models including the [[Learjet 55]], [[Learjet 31|31]], [[Learjet 60|60]], [[Learjet 45|45]], and [[Learjet 40]].

[[Gulfstream Aerospace]] explored winglets in the late 1970s and incorporated winglets in the [[Gulfstream III]], [[Gulfstream IV]] and [[Gulfstream V]]. The Gulfstream V [[range (aircraft)|range]] of {{cvt|6500|nmi|km}} allows nonstop routes such as New York–Tokyo, it holds over 70 world and national flight records.<ref name="nasa_c2r"/>
The Rutan combined winglets-vertical stabilizer appeared on his [[Beechcraft Starship]] business aircraft design that first flew in 1986.

Winglets are also applied to other business aircraft, reducing take-off distance to operate from smaller airports, and allowing higher cruise altitudes. Along winglets on new designs, aftermarket vendors developed retrofits. Winglet Technology, LLC of [[Wichita, Kansas]] should have tested its elliptical winglets designed to increase [[payload-range]] on [[hot and high]] departures to retrofit the [[Citation X]].<ref>{{cite news |work= Aero news network |url= http://www.aero-news.net/index.cfm?ContentBlockID=7c28af6c-9576-41d4-97df-88d10885156c |title= Winglets Coming For Citation X Bizjets |date= March 13, 2007}}</ref>

Conventional winglets were fitted to Rutan's [[Rutan Voyager]], the first aircraft to circumnavigate the world without refueling in 1986. The aircraft's wingtips were damaged, however, when they dragged along the runway during takeoff, removing about {{convert|1|ft|cm|sigfig=1}} from each wingtip, so the flight was made without benefit of winglets.<ref>{{cite web|url=http://www.centennialofflight.net/essay/Explorers_Record_Setters_and_Daredevils/rutan/EX32.htm |title=Dick Rutan, Jeana Yeager, and the Flight of the Voyager |publisher= U.S. Centennial of Flight Commission}}</ref>

==== Wingtip fence ====
A wingtip fence refers to the winglets including surfaces extending both above and below the wingtip, as described in Whitcomb's early research.<ref name="NASA innovation" /> Both surfaces are shorter than or equivalent to a winglet possessing similar aerodynamic benefits. The [[Airbus A310-300]] was the first airliner with wingtip fences in 1985.<ref>{{cite web |url= http://www.airbus.com/en/corporate/innovation/ |work= Corporate information – Innovation & technology |publisher= Airbus |title= From the A300 to the A380: Pioneering leadership |url-status= bot: unknown |archive-url= https://web.archive.org/web/20090421092103/http://www.airbus.com/en/corporate/innovation/ |archive-date= 2009-04-21 }}</ref> Other Airbus models followed with the [[Airbus A300-600|A300-600]], the [[A320ceo]], and the [[Airbus A380|A380]]. Other Airbus models including the [[Airbus A320 Enhanced]], [[A320neo]], [[Airbus A350|A350]] and [[A330neo]] have blended winglets rather than wingtip fences. The [[Antonov An-158]] uses wingtip fences.

==== Canted winglets ====
[[Boeing]] announced a new version of the [[Boeing 747|747]], the [[747-400]], in 1985, with an extended range and capacity, using a combination of winglets and increased span to carry the additional load. The winglets increased the 747-400's range by 3.5% over the 747-300, which is otherwise aerodynamically identical but has no winglets. The 747-400D variant lacks the wingtip extensions and winglets included on other 747-400s since winglets would provide minimal benefits on short-haul routes while adding extra weight and cost, although the -400D may be converted to the long-range version if needed.<ref name="bca_aero_17_wingtip_devices"/> Winglets are preferred for Boeing derivative designs based on existing platforms, because they allow maximum re-use of existing components. Newer designs are favoring increased span, other wingtip devices or a combination of both, whenever possible.{{citation needed|date=November 2017}}

The [[Ilyushin Il-96]] was the first Russian and modern jet to feature winglets in 1988. The [[Bombardier CRJ-100]]/200 was the first regional airliner to feature winglets in 1992. The [[Airbus A340|A340]]/[[Airbus A330|A330]] followed with canted winglets in 1993/1994. The [[Tupolev Tu-204]] was the first [[narrowbody]] aircraft to feature winglets in 1994. The [[Airbus A220]] (née CSeries), from 2016, has canted winglets. 

==== Blended winglets ====
A blended winglet is attached to the wing with a smooth curve instead of a sharp angle and is intended to reduce [[interference drag]] at the wing/winglet junction. A sharp interior angle in this region can interact with the [[boundary layer]] flow causing a drag inducing vortex, negating some of the benefit of the winglet. [[Seattle]]-based [[Aviation Partners]] develops blended winglets as retrofits for the [[Gulfstream II]], [[Hawker 800]] and the [[Falcon 2000]].

<gallery mode="packed" heights="140px">
File:Winglet and nav light arp.jpg|[[Boeing 747-400]] canted winglet
File:Lufthansa winglet (14511808755).jpg|[[A320 family|Airbus A320]] sharklet (blended winglet)
File:Delta Air Lines 767-400ER @LHR.jpg|[[Boeing 767#767-400ER|Boeing 767-400ER]] with raked wingtips
File:Wing.slat.600pix.jpg|[[Airbus A310-300]] wingtip fence
</gallery>

On February 18, 2000, blended winglets were announced as an option for the [[Boeing 737 Next Generation#737-800|Boeing 737-800]]; the first shipset was installed on 14 February 2001 and entered revenue service with [[Hapag-Lloyd Flug]] on 8 May 2001.<ref>{{cite web |url= http://boeing.com:80/commercial/737family/pf/pf_ng_milestones.html |archive-url= https://web.archive.org/web/20080429193504/http://boeing.com/commercial/737family/pf/pf_ng_milestones.html |url-status= dead |archive-date= 2008-04-29 |title= Next-Generation 737 Program Milestones |publisher= Boeing |access-date= 2019-02-05 }}</ref> The Aviation Partners/Boeing {{cvt|8|ft|m}} extensions decrease [[fuel economy in aircraft|fuel consumption]] by 4% for long-range flights and increase range by {{cvt|130 or 200|nmi|km}} for the 737-800 or the derivative [[Boeing Business Jet]] as standard.<ref name="bca_aero_17_wingtip_devices" /> Also offered for the [[737 Classic]], many operators have retrofitted their fleets with these for the fuel savings.{{citation needed|date=November 2018}} Aviation Partners Boeing also offers blended winglets for the [[Boeing 757|757]] and [[Boeing 767|767-300ER]].<ref>{{cite magazine |magazine= [[Aviation Week & Space Technology]] |date= February 23, 2009 |url= http://aviationweek.com/awin/american-airlines-set-debut-767-winglet-mod |title= American Airlines Set To Debut 767 Winglet Mod |author= Guy Norris |page= 39 |url-access= subscription}}</ref> In 2006 Airbus tested two candidate blended winglets, designed by Winglet Technology and Airbus for the [[Airbus A320 family]].<ref>{{cite news |url= http://www.boeing.com/news/frontiers/archive/2006/march/i_iw.html |at= Airbus to test new winglets for single-aisle jetliners |title= Industry Wrap |publisher= Boeing |work= Frontiers |volume= 4 |issue= 10 |date= March 2006}}</ref> In 2009 Airbus launched its "Sharklet" blended winglet, designed to enhance the [[payload-range]] of its [[A320 family]] and reduce fuel burn by up to 4% over longer sectors.<ref>{{cite press release |url= http://www.airbus.com/newsroom/press-releases/en/2013/07/american-airlines-takes-delivery-of-its-first-a320-family-aircraft.html |title= American Airlines takes delivery of its first A320 Family aircraft |publisher= Airbus |date= July 23, 2013 |access-date= November 1, 2017 |archive-date= November 7, 2017 |archive-url= https://web.archive.org/web/20171107005102/http://www.airbus.com/newsroom/press-releases/en/2013/07/american-airlines-takes-delivery-of-its-first-a320-family-aircraft.html |url-status= dead }}</ref> This corresponds to an annual CO<sub>2</sub> reduction of 700 tonnes per aircraft.<ref>{{cite press release |url= http://www.airbus.com/presscentre/pressreleases/press-release-detail/detail/korean-air-aerospace-to-manufacture-new-a320-family-sharklets/ |title= Korean Air Aerospace to manufacture and distribute Sharklets |publisher= Airbus |date= May 31, 2010 }}</ref> The A320s fitted with Sharklets were delivered beginning in 2012.<ref name="Airbus15Nov09">{{cite web |url =http://www.aircraft.airbus.com/presscentre/pressreleases/press-release-detail/detail/airbus-launches-sharklet-large-wingtip-devices-for-a320-family-with-commitment-from-air-new-zealan/ |title =Airbus launches "Sharklet" large wingtip devices for A320 Family with commitment from Air New Zealand |publisher =[[Airbus]] |date =15 November 2009 |url-status =dead |archive-url =https://web.archive.org/web/20171107021641/http://www.aircraft.airbus.com/presscentre/pressreleases/press-release-detail/detail/airbus-launches-sharklet-large-wingtip-devices-for-a320-family-with-commitment-from-air-new-zealan/ |archive-date =7 November 2017 }}</ref><ref name=":0">{{Cite web|last=Gardiner|first=Ginger|date=May 1, 2014|title=First A320neo features composite Korean Sharklets|url=https://www.compositesworld.com/articles/first-a320neo-in-final-assembly-features-composite-sharklets-made-in-korea|access-date=2020-09-09|website=CompositesWorld}}</ref> They are used on the [[A320neo]], the [[A330neo]] and the [[Airbus A350|A350]]. They are also offered as a retrofit option.<ref name=":0" /><ref>{{Cite web|title=Airbus Selects Korean Air Aerospace to manufacture Sharklet wingtips for the A330neo Family|url=https://www.airbus.com/newsroom/press-releases/en/2015/04/airbus-selects-korean-air-aerospace-to-manufacture-sharklet-wingtips-for-the-a330neo-family.html|archive-url=https://web.archive.org/web/20230126121852/https://www.airbus.com/newsroom/press-releases/en/2015/04/airbus-selects-korean-air-aerospace-to-manufacture-sharklet-wingtips-for-the-a330neo-family.html|url-status=dead|archive-date=January 26, 2023|access-date=2020-09-09|website=Airbus}}</ref>

==== Raked wingtip ====

Raked wingtips, where the tip has a greater [[wing sweep]] than the rest of the wing, are featured on some [[Boeing Commercial Airplanes]] to improve [[fuel efficiency]], takeoff and climb performance. Like winglets, they increase the effective [[wing aspect ratio]] and diminish [[wingtip vortices]], decreasing lift-induced drag. In testing by Boeing and NASA, they reduce drag by as much as 5.5%, compared to 3.5% to 4.5% for conventional winglets.<ref name="bca_aero_17_wingtip_devices" />  While an increase in span would be more effective than a same-length winglet, its [[bending moment]] is greater.  A {{cvt|3|ft|cm}} winglet gives the performance gain of a {{cvt|2|ft|cm}} span increase but has the bending force of a {{cvt|1|ft|cm}} span increase.<ref name="airspace">{{cite web |url= https://www.airspacemag.com/flight-today/how-things-work-winglets-2468375/ |title= How Things Work: Winglets |work= Air & Space Magazine |date= September 2001 |author= George C. Larson |publisher= Smithsonian}}</ref>
[[File:Anh-2-15222236062661656996940.jpg|thumb|The [[Boeing 787 Dreamliner]] is an example of raked wingtips utilization.]]
Raked wingtips offer several weight-reduction advantages relative to simply extending the conventional main [[wingspan]]. At high load-factor structural design conditions, the smaller [[Chord (aeronautics)|chords]] of the wingtip are subjected to less load, and they result in less induced loading on the outboard main wing. Additionally, the leading-edge [[Swept wing|sweep]] results in the [[Center of pressure (fluid mechanics)|center of pressure]] being located farther aft than for simple extensions of the span of conventional main wings. At high load factors, this relative aft location of the center of pressure causes the raked wingtip to be twisted more leading-edge down, reducing the bending moment on the inboard wing. However, the relative aft-movement of the center of pressure accentuates [[Aeroelasticity#Flutter|flutter]].<ref>{{Cite web|last=Herrick|first=Larry|date=June 12, 1998 |title=Blunt Leading-Edge Raked Wingtips|url=https://patentimages.storage.googleapis.com/71/cf/0d/66512395e96100/US6089502.pdf|access-date=2021-12-06|website=Google Patents}}</ref>

Raked wingtips are installed on the [[Boeing 767]]-400ER (first flight on October 9, 1999), all generations of [[Boeing 777]] (June 12, 1994) including the upcoming [[Boeing 777X|777X]], the 737-derived [[Boeing P-8 Poseidon]] (25 April 2009), all variants of the [[Boeing 787]] (December 15, 2009) (the cancelled [[Boeing 787#787-3|Boeing 787-3]] would have had a {{cvt|51.7|m|ft|order=flip}} wingspan to fit in [[ICAO#Aerodrome Reference Code|ICAO Aerodrome Reference Code]] D, as its wingspan was decreased by using blended winglets instead of raked wingtips <ref>{{cite web |url= http://www.aci-na.org/static/entransit/Gen.%20Rich%20Breuhaus.pdf |title= 787 Dreamliner: A New Airplane for a New World |author= Rich Breuhaus |date= 20 May 2008 |publisher= Boeing |work= ACI-NA Commissioners Conference |access-date= 2019-01-06 |archive-url= https://web.archive.org/web/20170307045010/http://www.aci-na.org/static/entransit/Gen.%20Rich%20Breuhaus.pdf |archive-date= 2017-03-07 |url-status= dead }}</ref>), and the [[Boeing 747-8]] (February 8, 2010). The Embraer [[E-jet E2]] and [[Embraer C-390 Millennium|C-390 Millennium]] wings also have raked wingtips.

==== Split-tip ====

[[File:Boeing 737-8 MAX Belyakov.jpg|thumb|upright|737 MAX split-tip winglet]]
The [[McDonnell Douglas MD-11]] was the first aircraft with split-tip winglets in 1990.

For the [[737 Next Generation]], third-party vendor [[Aviation Partners]] has introduced a similar design to the 737 MAX wingtip device known as the split scimitar winglet,<ref>{{cite web | url=http://www.aviationpartnersboeing.com/products_737_800_3.php | title=737-800-3 | work=Aviation Partners Boeing }}</ref> with [[United Airlines]] as the launch customer.<ref>{{cite press release | url= http://newsroom.united.com/2013-07-17-United-Airlines-is-First-to-Install-Split-Scimitar-Winglets | title= United is first to install Split Scimitar winglets |publisher= United Airlines | date=July 17, 2013}}</ref>

The [[Boeing 737 MAX]] uses a new type of wingtip device.<ref>{{cite web |url=http://www.nycaviation.com/2012/05/boeing-says-radical-new-winglets-on-737-max-will-save-more-fuel/ |title=Boeing Says Radical New Winglets on 737 MAX Will Save More Fuel |author= Matt Molnar  |date=2 May 2012  |work=NYCAviation }}</ref>  Resembling a three-way hybrid of a winglet, wingtip fence, and raked wingtip, Boeing claims that this new design should deliver an additional 1.5% improvement in fuel economy over the 10-12% improvement already expected from the 737 MAX.

==== Gliders ====
[[File:Schempp-Hirth Ventus 2b glider being launched at Lasham Airfield in UK.jpg|thumb|[[Schempp-Hirth Ventus-2]] [[glider (sailplane)|glider]] with factory winglets [[Gliding#winchlaunch|winch-launching]]]]

In 1987, [[mechanical engineering|mechanical engineer]] [[Peter Masak]] called on aerodynamicist [[Mark D. Maughmer]], an associate professor of aerospace engineering at the [[Pennsylvania State University]], about designing winglets to improve performance on his {{convert|15|m|ft|adj=on|sp=us}} wingspan racing [[sailplane]]. Others had attempted to apply Whitcomb's winglets to gliders before, and they did improve climb performance, but this did not offset the parasitic drag penalty in high-speed cruise. Masak was convinced it was possible to overcome this hurdle.<ref>{{cite web |url= http://www.engr.psu.edu/newsevents/EPS/v16n3_2000summer/tip.htm |title= The tip of the iceberg |author= Curtis Chan |date= Summer 2000 |volume= 16 |issue= 3 |work= Engineering Penn State magazine |url-status= bot: unknown |archive-url= https://web.archive.org/web/20040611220212/http://www.engr.psu.edu/newsevents/EPS/v16n3_2000summer/tip.htm |archive-date= 2004-06-11 }}</ref> By trial and error, they ultimately developed successful winglet designs for [[gliding competitions]], using a new PSU–90–125 [[airfoil]], designed by Maughmer specifically for the winglet application. At the 1991 [[World Gliding Championships]] in [[Uvalde, Texas]], the trophy for the highest speed went to a winglet-equipped 15-meter class limited wingspan glider, exceeding the highest speed in the unlimited span [[Glider competition classes|Open Class]], an exceptional result.<ref>{{cite journal|last=Masak|first=Peter|date=April–May 1992|title=Winglet Design for Sailplanes|journal=Free Flight|volume=1992|issue=2|page=8|issn=0827-2557|url=http://www.postfrontal.com/PDF/Winglets_01.pdf}}</ref> Masak went on to win the 1993 U.S. 15 Meter Nationals gliding competition, using winglets on his prototype [[Masak Scimitar]].<ref>{{cite web |url= http://ridgesewing.com/mifflin/contests.htm |title= Past Mifflin Contests |publisher= Mifflin Soaring Association}}</ref>

[[File:PSU-90-125.PNG|thumb|PSU-90-125 winglet [[airfoil]] profile]]
The Masak winglets were originally retrofitted to production sailplanes, but within 10 years of their introduction, most high-performance gliders were equipped from the factory with winglets or other wingtip devices.<ref>{{cite web |url= http://www.mandhsoaring.com/Why%20Winglets/WL-Soaring.pdf |title= About Winglets |author= Mark D. Maughmer |work= [[Soaring Magazine]] |date= June 2002 |author-link= Mark D. Maughmer }}</ref> It took over a decade for winglets to first appear on a production airliner, the original application that was the focus of the NASA development. Yet, once the advantages of winglets were proven in competition, adoption was swift with gliders. The point difference between the winner and the runner-up in soaring competition is often less than one percent, so even a small improvement in efficiency is a significant competitive advantage. Many non-competition pilots fitted winglets for handling benefits such as increased [[roll (flight)|roll rate]] and roll authority and reduced tendency for wing tip [[stall (flight)|stall]]. The benefits are notable, because sailplane winglets must be removable to allow the glider to be stored in a [[Trailer (vehicle)|trailer]], so they are usually installed only at the pilot's preference.{{citation needed|date=May 2015}}

The [[Glaser-Dirks DG-300|Glaser-Dirks DG-303]], an early glider derivative design, incorporating winglets as factory standard equipment.