Aircraft Winglets


Many of us who fly regularly have most probably seen a so-called winglet or wingtip device at the end of the wing of an airliner at least once. It is showing up more and more often on more and more types of aircraft, thus we felt it’s time to give an overview to our readers about these sometimes funny, sometimes cool and stylish looking aircraft parts.

Winglet on Virgin Atlantic A340-600 - c by Dan Valentine on Airliners.net

Winglet on Virgin Atlantic A340-600 - c by Dan Valentine on Airliners.net

History, Reason and Benefits

The initial theoretical concept goes back to times before even the Wright Brothers first took to the skies in 1905, but it was picked up and developed by Richard T. Whitcomb of NASA after the 1973 oil crisis – in order to reduce fuel consumption. The first tests were carried out in 1979/80 in cooperation with the U.S. Air Force. At almost the same time, but independent of any U.S. military organization, a private jet producer, LearJet exhibited a prototype in 1977: the LearJet 28 that featured the first winglets on a jet and a production aircraft. Flight tests made with and without winglets showed that the winglets increased range by about 6.5 percent and also improved directional stability for the LearJet- these two factors are the major reasons behind using this facility at any fixed wing aircraft ever since.

Airflow around the wingtip with or without a wingletA winglet is a (near) vertical extension of the wing tips. The upward angle of the winglet, its inward angle as well as its size and shape are critical for correct performance – this is why they can look quite different. Air rotating around the wing strikes the surface of the winglet that directs it in another direction – thus creating an extra force, basically converting otherwise wasted energy to thrust. This is a small contribution but can save a lot for an operator in an aircraft’s lifetime. Another potential benefit of winglets is that they reduce the strength of wingtip vortices, which trail behind the plane. When other aircraft pass through these vortices, the turbulent air can cause loss of control, possibly resulting in an accident.

Winglet Types

In general any wingtips that not end the wing simply horizontally are considered as some kind of a winglet. Even though in strictly technical terms Wingtip Fences are not real extensions of the wing, and Raked Wingtips do not have a vertical part, they are still widely considered as winglet variants.

WINGTIP FENCES are a special variant of winglets, that extend both upward and downward from the tip of the wing. Preferred by European plane-maker Airbus, it is featured on their full product range (except the A330/340 family and the future A350). The Airbus A300 was actually the first jet airliner to feature this kind of solution by default, but it was a very small version of the tool. Provided that most of the Airbus planes (including all A320 family jets) feature such wingtip fences, this may be the most seen and most produced winglet type. Even the new Airbus A380 double-decker features wingtip fences.

Airbus Winglets as seen from the outside

Airbus Winglets as seen from the outside

Airbus Winglets seen from onboard

Airbus Winglets as seen from onboard

BLENDED WINGLETS (the real “Winglets”) are the most popular winglet type, leveraged by Airbus, Boeing, Embraer, Bombardier but also by Russian Tupolev and Iljushin. Blended winglets were first introduced on the McDonnel Douglas MD-11 aircraft in 1990 with launch customer Finnair (it also features a smaller winglet at the bottom side of the wing). In contrast to Airbus who applies the wingtip fences by default on most of their aircraft (and the winglets on the A330/340 family), blended winglets are considered by Boeing for example as an optional extra feature on their products, except for the Boeing 747-400. For some of the older Boeing jets (737 and 757) such blended winglets have been offered as an aftermarket retrofit, these are the newer, tall designs and do not connect to the tip of the wing with a sharp angle, but with a curve instead. These winglets are popular among airlines that fly these aircraft on medium/long haul routes as most of the real fuel savings materialize while cruising. Longer flights mean longer cruising, thus larger fuel savings. And they also server as marketing surface for airline logos or web addresses usually.

Just recently the Boeing 767-300ER has received 3.4 m high (!) winglets produced by Aviation Partners Inc. with American Airlines as the launch-customer with Air New Zealand and Hawaiian Airlines following with orders of 5 and 8 aircrafts respectively. 141 shipsets have been pre-sold already as the forecasted fuel savings range around 4%-6% for medium/long-range flights. Airbus earlier tested similar blended winglets designed by Winglet Technology for the A320 series, but determined that their benefits did not warrant further development and they stayed with the wingtip fences instead. Aviation Partners Boeing claims that winglets on 737s and 757s have saved a collective 1.2 billion gal. of fuel since they were introduced and 11.5 million tonnes of CO2 while reducing those types’ noise footprint by 6.5%. It has sold winglets to 140 airlines and 95% of all 737NGs are fitted with them. It is working on four winglet concepts for the 777 and hopes to finalize a design for that aircraft type by December, 2008.

Blended Winglets on Several Aircraft Types

Blended Winglets on Several Aircraft Types

RAKED WINGTIPS are the most recent winglet variants (they are probably better classified as special wings, though), where the tip of the wing has a higher degree of sweep than the rest of the wing. They are widely referred to as winglets, but they are better described as integrated wingtip extensions as they are (horizontal) additions to the existing wing, rather than the previously described (near) vertical solutions. The stated purpose of this additional feature is to improve fuel economy, climb performance and to shorten takeoff field length. It does this in much the same way as “traditional” winglets do. In testing by Boeing and NASA, raked wingtips have been shown to reduce drag by as much as 5.5%, as opposed to improvements of 3.5% to 4.5% from conventional winglets. Airliners to use raked wingtips: Boeing 747-8, Boeing 767-400ER, Boeing 777(-200LR; -300ER; and freighter versions) plus the new Boeing 787 Dreamliner and the Airbus A350. The 747-8, the 787 and the A350 will have special, new kind of wings, which do not have a separate winglet, but have raked, and blended wingtips integrated – without a sharp angle between the wing and the winglet.

Raked Wingtips on the new Boeing 787 and Airbus A350

Raked Wingtips on the new Boeing 787 and Airbus A350

As you can see, wingtips/winglets have developed and changed very much over the last 30 years, but are becoming the standard, which is not proven better by anything else than the wing designs of future aircraft by the largest airplane-makers that feature a built-in winglet at the tip of their new, revolutionary wings.

(Most of the winglet pictures in the montage images taken from airliners.net taken by several photographers.)

by balint01

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20 Responses to “Aircraft Winglets”


  1. 1 th December 3, 2008 at 1:44 am

    thxs for the info for my science project iwon thxs to you

  2. 2 balint01 December 5, 2008 at 11:35 pm

    Hi “th”,

    Congratulations, and thanks for sharing the encouraging words! :) What kind of competition was it at what part of the world?

  3. 3 M Haqiqi J February 8, 2009 at 11:14 am

    What a wonderful article. A simple writing complemented with a pictures.

  4. 4 benjo February 15, 2009 at 10:41 pm

    Why are the airlines not retrofit their old aircrafts with winglets?

  5. 5 szafi February 16, 2009 at 10:32 am

    Because it’s very expensive and depending on the age of the aircraft the return on investment is not always guaranteed.
    There is another point though: if airlines some years ago could have foreseen today’s fuel prices, they would have been more convinced aboit its necessity. But youz know sometimes companies don’t mind long term costs in case they can avoid immediate investments. That’s why they ususally lease their aircrafts, too.

  6. 6 GM RAHNUMA April 15, 2009 at 10:38 pm

    Yoc cannot put simply the Winglets or Wing fences to any old aircraft which was not designed with these accessories. It is designer who decide the necessity of winglet, wing fence or raked wing tip on an Aircraft before manufacturing or while designing.Though it is beneficial to have blended winglet but sometime the compulsion of keeping the aircraft span under limit, it is avoided as it happened with A380.

  7. 7 balint01 November 16, 2009 at 11:04 am

    At the 2009 Dubai Airshow Airbus has announced that it’s rolling out blended winglets on its A320 family, thus moving away from the wingtip fences. The new terminology they introduced for the new Airbus A320 blended winglets: “Sharklets“. Nice marketing idea from Airbus, but those are simple blended winglets.

    http://www.airbus.com/en/presscentre/pressreleases/pressreleases_items/09_11_15_a320_sharklet_new_zealand.html

  8. 8 Peter April 13, 2010 at 8:29 am

    Hi
    Very nice article covering an interesting issue. Two imidiate thougths came to mind:

    1 sails should also be improved by intorducing winglets

    2 If loocking on bird wing tips many more differsnt winglet configurations occur, could be of interest to look at

    best
    Peter

  9. 9 Name May 3, 2010 at 2:12 pm

    This helped me so much!!! I think whoever wrote this is a gineous!

  10. 10 DR.G.M.RAHNUMA May 22, 2010 at 7:16 pm

    Yoc cannot put simply the Winglets or Wing fences to any old aircraft which was not designed with these accessories. It is designer who decide the necessity of winglet, wing fence or raked wing tip on an Aircraft before manufacturing or while designing.Though it is beneficial to have blended winglet but sometime the compulsion of keeping the aircraft span under limit, it is avoided as it happened with A380, because after putting winglet the span was exceeding more than 80 mtrs which was a violation of ICAO limitations.

  11. 11 jon s February 3, 2011 at 5:58 am

    definitely one of my three sources for science fair

  12. 12 santhosh February 14, 2012 at 8:28 am

    useful datas..thnz lot

  13. 13 sagar June 12, 2013 at 5:10 am

    Great article. Answered a lot of questions.


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  2. 2 SocialYell Sustainability News :: environment :: American Airlines fuel economy Trackback on July 12, 2009 at 4:05 am
  3. 3 Finnair’s Last MD-11 Passenger Flight « Airline world Trackback on February 23, 2010 at 3:43 pm
  4. 4 Finnair’s Last MD-11 Passenger Flight « Airline world Trackback on February 23, 2010 at 3:43 pm
  5. 5 Winglets | Today's Hot Trackback on June 19, 2011 at 4:22 am
  6. 6 First Boeing 747-8 Intercontinental for Lufthansa « Airline world Trackback on June 8, 2012 at 1:32 am
  7. 7 References | Biomimetic winglet based on morphological features of whale pectoral flippers Trackback on August 27, 2013 at 3:46 pm

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