Editing Delta wing

{{short description|Triangle shaped aircraft wing configuration}}
{{about|the wing shape|the racing car|DeltaWing}}
[[File:Mirage 2000 taking off.jpg|thumb|The [[Dassault Mirage 2000]] is among the most successful delta-winged fighter jets, being used by many countries to this day.]]
A '''delta wing''' is a [[wing]] shaped in the form of a triangle. It is named for its similarity in shape to the Greek uppercase letter [[delta (letter)|delta]] (Δ).

Although long studied, the delta wing did not find significant practical applications until the [[Jet Age]], when it proved suitable for high-speed [[Subsonic aircraft|subsonic]] and&nbsp;[[supersonic]] flight.<ref>{{Cite web |last=Lauten, Jr. |first=William T. |last2=Mitcham |first2=Grady L. |date=1951-05-14 |title=NOTE ON FLUTTER OF A 600 DELTA WING ENCOUNTERED AT LOW-SUPERSONIC SPEEDS DURING THE FLIGHT OF A ROCKET-PROPELLED MODEL |url=https://ntrs.nasa.gov/api/citations/19930086580/downloads/19930086580.pdf |website=ntrs.nasa.gov}}</ref> At the other end of the speed scale, the [[Rogallo wing|Rogallo flexible wing]] proved a practical design for the [[hang glider]] and other [[ultralight aircraft]]. The delta wing form has unique aerodynamic characteristics and structural advantages. Many design variations have evolved over the years, with and without additional stabilising surfaces.

==General characteristics==
===Structure===
The long root chord of the delta wing and minimal area outboard make it structurally efficient. It can be built stronger, stiffer and at the same time lighter than a [[swept wing]] of equivalent [[aspect ratio]] and lifting capability. Because of this it is easy and relatively inexpensive to build—a substantial factor in the success of the [[Mikoyan-Gurevich MiG-21|MiG-21]] and [[Dassault Mirage|Mirage]] aircraft series.<ref>{{Cite book |last1=Sahoo |first1=Devabrata |url=https://books.google.com/books?id=TYshEQAAQBAJ&dq=%C2%A0simplicity+delta+wing+stronger+stiffer&pg=PA50 |title=Advances in Aerospace Technologies |last2=Sharma |first2=Abhishek |last3=Rajput |first3=Shailendra |date=2024-10-23 |publisher=CRC Press |isbn=978-87-7004-638-1 |pages=50 |language=en}}</ref>

Its long root chord also allows a deeper structure for a given [[aerofoil]] section. This both enhances its weight-saving characteristic and provides greater internal volume for fuel and other items, without a significant increase in drag. However, on supersonic designs the opportunity is often taken to use a thinner aerofoil instead, in order to actually reduce drag.

===Aerodynamics===

====Low-speed flight and vortex lift====
Like any wing, at low speeds a delta wing requires a high [[angle of attack]] to maintain lift. At a sufficiently high angle the wing exhibits [[flow separation]], together with an associated high drag.<ref name=":0">{{Cite book|title=High Angle of Attack Aerodynamics: Subsonic, Transonic, and Supersonic Flows|url=https://archive.org/details/highangleattacka00romj|url-access=limited|last=Rom|first=Josef|date=1992|publisher=Springer New York|isbn=9781461228240|location=New York, NY|pages=[https://archive.org/details/highangleattacka00romj/page/n24 15]–23|oclc=853258697}}</ref>

Ordinarily, this flow separation leads to a loss of lift known as the [[Stall (fluid dynamics)|stall]]. However, for a sharply-swept delta wing, as air spills up round the leading edge it flows inwards to generate a characteristic [[vortex]] pattern over the upper surface. The lower extremity of this vortex remains attached to the surface and also accelerates the airflow, maintaining lift. For intermediate sweep angles, a retractable "moustache" or fixed [[leading-edge root extension]] (LERX) may be added to encourage and stabilise vortex formation. The ogee or "wineglass" double-curve, seen for example on [[Concorde]], incorporates this forward extension into the profile of the wing.

In this condition, the centre of lift approximates to the centre of the area covered by the vortex.

====Subsonic flight====
In the subsonic regime, the behaviour of a delta wing is generally similar to that of a [[swept wing]]. A characteristic sideways element to the airflow develops. In this condition, lift is maximised along the leading edge of the wing, where the air is turned most sharply to follow its contours. Especially for a slender delta, the centre of lift approximates to halfway back along the leading edge.

The sideways effect also leads to an overall reduction in lift and in some circumstances can also lead to an increase in drag. It may be countered through the use of leading-edge slots, wing fences and related devices.

====Transonic and low-supersonic flight====
[[File:194th Fighter-Interceptor Squadron - Convair F-106A-135-CO Delta Dart 59-0136.jpg|thumb|Convair made several supersonic deltas. This is an [[Convair F-106 Delta Dart|F-106 Delta Dart]], a development of their earlier F-102 Delta Dagger]]
With a large enough angle of rearward sweep, in the [[transonic]] to low [[supersonic]] speed range the wing's leading edge remains behind the [[shock wave]] boundary or [[shock cone]] created by the leading edge root.

This allows air below the leading edge to flow out, up and around it, then back inwards creating a sideways flow pattern similar to subsonic flow. The lift distribution and other aerodynamic characteristics are strongly influenced by this sideways flow.<ref name="mason10-1">Mason, Chap. 10, pp. 9–12.</ref>

The rearward sweep angle lowers the airspeed normal to the leading edge of the wing, thereby allowing the aircraft to fly at high [[subsonic flight|subsonic]], transonic, or supersonic speed, while the subsonic lifting characteristics of the airflow over the wing are maintained.

Within this flight regime, drooping the leading edge within the shock cone increases lift, but not drag to any significant extent.<ref>Boyd, Migotzky and Wetzel; "A Study of Conical Camber for Triangular and Sweptback Wings", Research Memorandum A55G19, NACA, 1955.[http://nix.nasa.gov/search.jsp?R=19930090334&qs=N%3D17%2B4293246867]{{dead link|date=June 2021|bot=medic}}{{cbignore|bot=medic}}</ref> Such conical leading edge droop was introduced on the production [[Convair F-102A Delta Dagger]] at the same time that the prototype design was reworked to include [[Area rule|area-ruling]]. It also appeared on Convair's next two deltas, the [[F-106 Delta Dart]] and [[B-58 Hustler]].<ref>Mason, Chap. 10, p. 16.</ref>

====High-speed supersonic waveriding====
At high supersonic speeds, the shock cone from the leading edge root angles further back to lie along the wing surface behind the leading edge. It is no longer possible for the sideways flow to occur and the aerodynamic characteristics change considerably.<ref name="mason10-1" /> It is in this flight regime that the [[waverider]] design, as used on the [[North American XB-70 Valkyrie]], becomes practicable. Here, a shock body beneath the wing creates an attached shockwave and the high pressure associated with the wave provides significant lift without increasing drag.

==Design variations==
{{Anchor|ogee delta}}
{{anchor|cropped delta|tailed delta}}

[[File:Concorde on Bristol.jpg|thumb|Aérospatiale-BAC [[Concorde]] shows off its ogee wing]]

Variants of the delta wing plan offer improvements to the basic configuration.<ref>{{Cite book|title=Introduction to aerospace engineering with a flight test perspective|last=Corda|first=Stephen|publisher=John Wiley & Sons|year=2017|isbn=9781118953372|location=Chichester, West Sussex, United Kingdom|pages=408–9|oclc=967938446}}</ref>

'''Cropped delta'''&nbsp;– tip is cut off. This helps maintain lift outboard and reduce wingtip flow separation (stalling) at high angles of attack. Most deltas are cropped to at least some degree.

In the {{Anchor|compound delta|double delta|cranked arrow}}'''compound delta''', '''double delta''' or '''cranked arrow''', the leading edge is not straight. Typically the inboard section has increased sweepback, creating a controlled high-lift vortex without the need for a foreplane. Examples include the [[J 35 Draken|Saab Draken]] fighter, the experimental [[General Dynamics F-16XL]], and the Hawker Siddeley HS. 138 VTOL concept. The '''ogee delta''' (or '''{{anchor|ogival delta}}ogival delta''') used on the Anglo-French [[Concorde]] [[supersonic airliner]] is similar, but with the two sections and cropped wingtip merged into a smooth [[ogee]] curve.

{| align=center style="text-align:center;"
|-
|[[File:Wing tailless delta.svg|112px|alt=" "]]<br />Tailless delta
|[[File:Wing cropped delta.svg|112px|alt=" "]]<br />Cropped delta
|[[File:wing compound delta.svg|112px|alt=" "]]<br />Compound delta
|[[File:wing cranked arrow.svg|112px|alt=" "]]<br />Cranked arrow
|[[File:Wing ogival delta.svg|112px|alt=" "]]<br />Ogival delta
|[[File:Wing delta.svg|112px|alt=" "]]<br />Tailed delta
|} <!-- table originally copied from [[Wing configuration]] -->

'''Tailed delta'''&nbsp;– adds a conventional tailplane (with horizontal tail surfaces), to improve handling.  Common on Soviet types such as the [[Mikoyan-Gurevich MiG-21]].

'''Canard delta'''&nbsp;– Many modern fighter aircraft, such as the [[JAS 39 Gripen]], the [[Eurofighter Typhoon]] and the [[Dassault Rafale]] use a combination of [[Canard (aeronautics)|canard]] foreplanes and a delta wing.

===Tailless delta===
[[File:Saab Draken.jpg|thumb|The [[Saab 35 Draken]] was a successful tailless double-delta design]]
Like other [[tailless aircraft]], the tailless delta wing is not suited to high wing loadings and requires a large wing area for a given aircraft weight. The most efficient aerofoils are unstable in pitch and the tailless type must use a less efficient design and therefore a bigger wing. Techniques used include:
* Using a less efficient aerofoil which is inherently stable, such as a symmetrical form with zero camber, or even reflex camber near the trailing edge,
* Using the rear part of the wing as a lightly- or even negatively-loaded horizontal stabiliser:
**Twisting the outer leading edge down to reduce the incidence of the wing tip, which is behind the main centre of lift. This also improves stall characteristics and can benefit supersonic cruise in other ways.
**Moving the centre of mass forwards and trimming the elevator to exert a balancing downforce. In the extreme, this reduces the craft's ability to pitch its nose up for takeoff and landing.
The main advantages of the tailless delta are structural simplicity and light weight, combined with low aerodynamic drag. These properties helped to make the [[Dassault Mirage III]] one of the most widely manufactured supersonic fighters of all time.

===Tailed delta===
A conventional tail stabiliser allows the main wing to be optimised for lift and therefore to be smaller and more highly loaded. Development of aircraft equipped with this configuration can be traced back to the late 1940s.<ref>Allward 1983, pp. 11–12.</ref>

When used with a T-tail, as in the [[Gloster Javelin]], like other wings a delta wing can give rise to a "[[deep stall]]" in which the high angle of attack at the stall causes the turbulent wake of the stalled wing to envelope the tail. This makes the elevator ineffective and the airplane cannot recover from the stall.<ref>{{Citation | url = http://www.thunder-and-lightnings.co.uk/javelin/history.php | title = Gloster Javelin History | publisher = Thunder & Lightnings | date = 4 April 2012 | place = UK | access-date = 10 February 2011 | archive-date = 9 June 2011 | archive-url = https://web.archive.org/web/20110609224809/http://www.thunder-and-lightnings.co.uk/javelin/history.php | url-status = live }}.</ref> In the case of the Javelin, a [[Stall (fluid dynamics)#Warning and safety devices|stall warning device]] was developed and implemented for the Javelin following the early loss of an aircraft to such conditions.<ref name ="pat 6">Patridge 1967, p. 6.</ref> Gloster's design team had reportedly opted to use a tailed delta configuration out of necessity, seeking to achieve effective manoeuvrability at relatively high speeds for the era while also requiring suitable controllability when being flown at the slower landing speeds desired.<ref>Patridge 1967, pp. 3–4.</ref>

===Canard delta===
[[File:Eurofighter 9803 2.jpg|thumb|The [[Eurofighter Typhoon]] has a canard delta wing configuration.]]
A lifting-canard delta can offer a smaller shift in the center of lift with increasing Mach number compared to a conventional tail configuration.

An unloaded or free-floating canard can allow a safe recovery from a high angle of attack. Depending on its design, a canard surface may increase or decrease longitudinal stability of the aircraft.<ref>{{Citation |last=Probert |first=B |publisher=NATO |url=http://ftp.rta.nato.int/public//PubFulltext/RTO/EN/RTO-EN-004///$EN-004-19.pdf |title=Aspects of Wing Design for Transonic and Supersonic Combat |url-status=dead |archive-url=https://web.archive.org/web/20110517202722/http://ftp.rta.nato.int/public/ |archive-date=17 May 2011 }}.</ref><ref>{{Citation |publisher=Mach flyg |url=http://www.mach-flyg.com/utg80/80jas_uc.html |title=Aerodynamic highlights of a fourth generation delta canard fighter aircraft |url-status=dead |archive-url=https://web.archive.org/web/20141127200736/http://www.mach-flyg.com/utg80/80jas_uc.html |archive-date=27 November 2014 }}.</ref>

A canard delta foreplane creates its own trailing vortex. If this vortex interferes with the vortex of the main delta wing, this can adversely affect the airflow over the wing and cause unwanted and even dangerous behaviour. In the close-coupled configuration, the canard vortex couples with the main vortex to enhance its benefits and maintain controlled airflow through a wide range of speeds and angles of attack. This allows both improved manoeuvrability and lower stalling speeds, but the presence of the foreplane can increase drag at supersonic speeds and hence reduce the aircraft's maximum speed.

==History==

===Early research===
Triangular stabilizing fins for rockets were described as early as 1529-1556 by the Austrian military engineer [[Conrad Haas]] and in the 17th century by the Polish-Lithuanian military engineer [[Kazimierz Siemienowicz]].<ref>{{cite web | trans-title = Corad Haas rocket pioneer in Transylvania | url = http://www.sibiweb.de/vip/haas/ | title = Corad Haas Raketenpionier in Siebenbürgen | work = Beruehmte Siebenbuerger Sachsen | publisher = Siebenbürgen und die Siebenbürger Sachsen im Internet | language = de | access-date = 2010-09-09 | archive-date = 2018-09-17 | archive-url = https://web.archive.org/web/20180917161453/http://www.sibiweb.de/vip/haas/ | url-status = live }}</ref><ref>{{Citation | url = http://www.nasa.gov/pdf/153410main_Rockets_History.pdf | archive-url = https://web.archive.org/web/20100119181932/http://www.nasa.gov/pdf/153410main_Rockets_History.pdf | url-status = dead | archive-date = 2010-01-19 | title = New Rocket Guide | publisher = NASA}}.</ref><ref>{{Citation | first = Bolesław | last = Orłowski | title = Technology and Culture | volume = 14 | number = 3 |date=Jul 1973 | pages = 461–73 | publisher = JStor | doi = 10.2307/3102331 | jstor=3102331| s2cid = 113306514 }}.</ref> However, a true lifting wing in delta form did not appear until 1867, when it was [[patent]]ed by J.W. Butler and E. Edwards in a design for a low-aspect-ratio, dart-shaped rocket-propelled aeroplane. This was followed by various similarly dart-shaped proposals, such as a biplane version by Butler and Edwards, and a jet-propelled version by the Russian [[Nicholas de Telescheff]].<ref>Wragg, David W.; ''Flight Before Flying'', Osprey, 1974, pp. 87-88, 96.</ref> In 1909 a variant with a [[canard (aeronautics)|canard foreplane]] was experimented with by the Spanish sculptor Ricardo Causarás.<ref>[http://centenariaviacio.catedradr.com/site/upload/ficheros/d-09.pdf "El Aeroplano-Monoplano Causarás en la Presna de 1909"]. ''1909-2009 100 Anos de Aviacion Espanola''. Generalitat Valencia. 2002. Retrieved 17 April 2023.</ref><ref>[http://centenariaviacio.catedradr.com/site/upload/ficheros/d-04b.pdf Patent application 46026 "Aeroplano Monoplano Causarás"]. Ricardo Causarás. 1909. Retrieved 17 April 2023.</ref>

Also in 1909, British aeronautical pioneer [[J. W. Dunne]] patented his tailless stable aircraft with conical wing development. The patent included a broad-span biconical delta, with each side bulging upwards towards the rear in a manner characteristic of the modern [[Rogallo wing]].<ref>J.W. Dunne; ''Provisional Patent: Improvements Relating to Aeroplanes'', UK Patent No. 8118, Date of Application 5 April 1909. [http://worldwide.espacenet.com/espacenetDocument.pdf?ND=5&flavour=trueFull&locale=en_EP&FT=D&date=19100331&CC=GB&NR=190908118A Copy on Espacenet] {{Webarchive|url=https://web.archive.org/web/20211001034352/https://worldwide.espacenet.com/publicationDetails/originalDocument?ND=5&flavour=trueFull&locale=en_EP&FT=D&date=19100331&CC=GB&NR=190908118A |date=2021-10-01 }}</ref> During the following year, in America U. G. Lee and W. A. Darrah patented a similar biconical delta winged aeroplane with an explicitly rigid wing. It also incorporated a proposal for a flight control system and covered both gliding and powered flight.<ref name="woodhams">Woodhams, Mark and Henderson, Graeme; "Did we really fly Rogallo wings?", ''Skywings'', June 2010.</ref><ref>Lee, U. G. and Darrah, H.; US patent 989,7896, filed 15 February 1910, granted 18 April 1911.</ref> None of these early designs is known to have successfully flown although, in 1904, Lavezzani's hang glider featuring independent left and right triangular wings had left the ground, and Dunne's other tailless swept designs based on the same principle would fly.<ref name="woodhams"/>

The practical delta wing was pioneered by German aeronautical designer [[Alexander Lippisch]] in the 1930s, using a thick cantilever wing without any tail. His first such designs, for which he coined the name "Delta", used a very gentle angle so that the wing appeared almost straight and the wing tips had to be cropped sharply (see below). His first such delta flew in 1931, followed by four successively improved examples.<ref name= secret>{{cite book | last = Ford| first= Roger| title= Germany's secret weapons in World War II| year= 2000| publisher= MBI Publishing | location = Osceola, WI | isbn=0-7603-0847-0|url=https://archive.org/details/germanyssecretwe0000ford | url-access = registration| quote = Lippisch.| edition =1st |page=[https://archive.org/details/germanyssecretwe0000ford/page/36 36]}}</ref><ref name=pop1931>{{Citation | url = https://books.google.com/books?id=ESgDAAAAMBAJ&pg=PA65 | title = New Triangle Plane Is Tailless | date = December 1931 | newspaper = Popular Science | page = 65 | access-date = 2016-10-10 | archive-date = 2014-06-27 | archive-url = https://web.archive.org/web/20140627194855/http://books.google.com/books?id=ESgDAAAAMBAJ&pg=PA65 | url-status = live }}.</ref> These prototypes were not easy to handle at low speed and none saw widespread use.<ref>{{cite book | last1 = Madelung | first1 = Ernst Heinrich | last2 = Hirschel | first2 = Horst | last3 = Prem | first3 = Gero | title = Aeronautical research in Germany: from Lilienthal until today | year = 2004 | publisher = Springer | location = Berlin | isbn = 3-540-40645-X | url = https://books.google.com/books?id=OoFcHOLpCskC&q=Lippisch%20Horten&pg=PA168 | edition = American | access-date = 2020-10-04 | archive-date = 2021-10-01 | archive-url = https://web.archive.org/web/20211001034351/https://books.google.com/books?id=OoFcHOLpCskC&q=Lippisch+Horten&lpg=PA168 | url-status = live }}</ref><ref>{{cite book |last1 = Wohlfahrt |first1 = Karl |last2 = Nickel |first2 = Michael |title = Schwanzlose flugzeuge : ihre auslegung und ihre eigenschaften |year = 1990 |publisher = Birkhauser |trans-title = Tailless aircraft: their design & properties |location = Basel |isbn = 3-7643-2502-X |url = https://books.google.com/books?id=33fBLs7FhQ8C&q=Lippisch%20Horten&pg=PA577 |access-date = 13 February 2011 |pages = 577–78 |language = de |quote = [Lippisch Delta I and Horten H I] Both these aircraft shown, how not to do it. |archive-date = 1 October 2021 |archive-url = https://web.archive.org/web/20211001034351/https://books.google.com/books?id=33fBLs7FhQ8C&q=Lippisch+Horten&lpg=PA577 |url-status = live }}</ref>

===Subsonic thick wing===
[[File:Vulcan.delta.arp.jpg|thumb|right|The [[Avro Vulcan]] bomber had a thick wing]]
During the latter years of [[World War II]], Alexander Lippisch refined his ideas on the high-speed delta, substantially increasing the sweepback of the wing's leading edge. An experimental glider, the [[Lippisch DM-1|DM-1]], was built to test the aerodynamics of the proposed [[Lippisch P.13a|P.13a]] high-speed [[interceptor aircraft|interceptor]].<ref>{{Citation | publisher = Youtube | url = https://www.youtube.com/watch?v=MvtxjSrImHw | last = Grommo | date = 17 May 2008 | title = Lippisch P13a Supersonic Ramjet Fighter footage | format = video | access-date = 27 November 2016 | archive-date = 15 April 2016 | archive-url = https://web.archive.org/web/20160415131015/https://www.youtube.com/watch?v=mvtxjsrimhw | url-status = live }}.</ref> Following the end of hostilities, the DM-1 was completed on behalf of the [[United States]] and the shipped to [[Langley Field]] in [[Virginia]] for examination by [[NACA]] (National Advisory Committee for Aeronautics, forerunner of today's [[NASA]]) It underwent significant alterations in the US, typically to lower its drag, resulting in the replacement of its large vertical stabilizer with a smaller and more conventional counterpart, along with a normal cockpit canopy taken from a [[Lockheed P-80 Shooting Star]].<ref>[http://apps.dtic.mil/dtic/tr/fulltext/u2/a801410.pdf "Research Memorandum L7F16"] {{Webarchive|url=https://web.archive.org/web/20170503011249/http://www.dtic.mil/dtic/tr/fulltext/u2/a801410.pdf |date=2017-05-03 }}, NACA, 5 August 1947.</ref>

The work of French designer [[Nicolas Roland Payen]] somewhat paralleled that of Lippisch. During the 1930s, he had developed a tandem delta configuration with a straight fore wing and steep delta aft wing, similar to that of Causarás. The outbreak of the Second World War brought a halt to flight testing of the [[Payen PA-22|Pa-22]], although work continued for a time after the project garnered German attention.<ref name="Lepage">{{cite book |last=LePage |first=Jean-Denis G. G. |title=Aircraft of the Luftwaffe, 1935-1945: an illustrated guide |year=2009 |publisher=McFarland |page=243 |isbn=978-0-7864-3937-9}}</ref> During the [[postwar]] era, Payen flew an experimental tailless delta jet, the [[Payen Pa.49|Pa.49]], in 1954, as well as the tailless pusher-configuration [[Payen Arbalète|Arbalète]] series from 1965. Further derivatives based on Payen's work were proposed but ultimately went undeveloped.<ref name="JAWA72">{{cite book |title= Jane's All the World's Aircraft 1972–73 |last= Taylor |first= John W. R. |year=1972 |publisher= Sampson Low, Marston & Co. Ltd |location= London |pages=71–2}}</ref><ref name=JAWA73>{{cite book |title= Jane's All the World's Aircraft 1973-74 |last= Taylor |first= John W. R. |year=1973|publisher=Jane's Yearbooks |location= London |isbn=0-354-00117-5 |pages=75–6}}</ref>

Following the war, the British developed a number of subsonic jet aircraft that harnessed data gathered from Lippisch's work. One such aircraft, the [[Avro 707]] research aircraft, made its first flight in 1949.<ref>Hygate, Barrie; ''British Experimental Jet Aircraft'', Argus, 1990.</ref> British military aircraft such as the [[Avro Vulcan]] (a [[strategic bomber]]) and [[Gloster Javelin]] (an all-weather fighter) were among the first delta-equipped aircraft to enter production. Whereas the Vulcan was a classic tailless design, the Javelin incorporated a tailplane in order to improve low-speed handling and high-speed manoeuvrability, as well as to allow a greater [[centre of gravity]] range.<ref>{{Citation | last = Partridge | first = J | title = Number 179 – The Gloster Javelin 1-6 | publisher = Profile | year = 1967}}.</ref> Gloster proposed a refinement of the Javelin that would have, amongst other changes, decreased wing thickness in order to achieve supersonic speeds of up to Mach 1.6.<ref>Buttler, 2017, pp. 94, 98-100.</ref>

===Supersonic thin wing===
[[File:SSSR-MiG-21SM(DN-ST-82-10891).jpg|thumb| The [[MiG-21]] fighter had a conventional tail]]
The American aerodynamicist [[Robert Thomas Jones (engineer)|Robert T. Jones]], who worked at NACA during the Second World War, developed the theory of the thin delta wing for supersonic flight. First published in January 1945, his approach contrasted with that of Lippisch on thick delta wings. The thin delta wing first flew on the [[Convair XF-92]] in 1948, making it the first delta-winged jet plane to fly.<ref>Jones, Lloyd, S.; ''U.S. Fighters'', Aero, 1975. p.247.</ref> It provided a successful basis for all practical supersonic deltas and the configuration became widely adopted.<ref>Von Karman, "Aerodynamics: Selected Topics in the Light of their Historical Development." 1954.</ref><ref>Hallion, Richard. "Lippisch, Gluhareff and Jones: The Emergence of the Delta Planform." ''Aerospace Historian'', March 1979.</ref>

During the late 1940s, the British aircraft manufacturer [[Fairey Aviation]] became interested in the delta wing,<ref name = "wood 73">Wood 1975, p. 73.</ref> its proposals led to the experimental [[Fairey Delta 1]] being produced to [[List of Air Ministry specifications|Air Ministry Specification E.10/47]].<ref name = "wood 74">Wood 1975, p. 74.</ref> A subsequent experimental aircraft, the [[Fairey Delta 2]] set a new [[Flight airspeed record|World air speed record]] on 10 March 1956, achieving 1,132&nbsp;mph (1,811&nbsp;km/h) or Mach 1.73.<ref name = "WG777 ind his">[http://www.rafmuseum.org.uk/documents/collections/85-A-10-Fairey-FD-2-WG777.pdf "Individual History: Fairey FD-2 Delta WG777/7986M."] {{Webarchive|url=https://web.archive.org/web/20200626142604/http://www.rafmuseum.org.uk/documents/collections/85-A-10-Fairey-FD-2-WG777.pdf |date=2020-06-26 }} ''Royal Air Force Museum'', Retrieved: 13 December 2016.</ref><ref name = "50 years flight">[https://www.flightglobal.com/news/articles/50-years-ago-16-mar-1956-205374/ "50 years ago: 16 Mar 1956."] {{Webarchive|url=https://web.archive.org/web/20161220154526/https://www.flightglobal.com/news/articles/50-years-ago-16-mar-1956-205374/ |date=20 December 2016 }} ''Flight International'', 10 March 2006.</ref><ref name = "wood 77">Wood 1975, p. 77.</ref><ref name = "rafmus over">[http://www.rafmuseum.org.uk/research/collections/fairey-fd2/ "Fairey FD2."] {{Webarchive|url=https://web.archive.org/web/20200628012952/http://www.rafmuseum.org.uk/research/collections/fairey-fd2/ |date=2020-06-28 }} ''Royal Air Force Museum'', Retrieved: 13 December 2016.</ref> This raised the record above 1,000&nbsp;mph for the first time and broke the previous record by 310&nbsp;mph, or 37 per cent; never before had the record been raised by such a large margin.<ref name = "50 years flight"/><ref name = "wood 79">Wood 1975, p. 79.</ref>

In its original tailless form, the thin delta was used extensively by the American aviation company [[Convair]] and by the French aircraft manufacturer [[Dassault Aviation]]. The supersonic [[Convair F-102 Delta Dagger]] and transonic [[Douglas F4D Skyray]] were two of the first operational jet fighters to feature a tailless delta wing when they entered service in 1956.<ref>{{citation |title=Early Supersonic Fighters of the West |last= Gunston |first=Bill |year= 1976 |publisher= Ian Allan Ltd. |location=Shepperton |isbn=0-7110-0636-9 |id= 103/74 |pages=181 and 230}}</ref> Dassault's interest in the delta wing produced the [[Dassault Mirage]] family of combat aircraft, especially the highly successful [[Dassault Mirage III|Mirage III]]. Amongst other attributes, the Mirage III was the first Western European combat aircraft to exceed Mach 2 in horizontal flight.<ref name="Mirage III">[https://web.archive.org/web/20151218081714/http://www.dassault-aviation.com/fr/passion/avions/dassault-militaires/mirage-iii/?xtmc=mirage-iii&xtrc=0%20Mirage%20III "Mirage III."] ''Dassault Aviation'', 18 December 2015.</ref>

The tailed delta configuration was adopted by the [[TsAGI]] (Central Aero and Hydrodynamic Institute, [[Moscow]]), to improve high [[angle-of-attack]] handling, manoeuvrability and centre of gravity range over a pure delta planform. The resulting TsAGI S-12 airfoil was used in the [[Mikoyan-Gurevich MiG-21]] ("Fishbed"), which became the most widely built combat aircraft of the 1970s.<ref>Sweetman, Bill & Gunston, Bill; ''Soviet Air Power: An Illustrated Encyclopedia.'' Salamander, 1978, p. 122.</ref>

===Close-coupled canard===
[[File:Saab viggen underside.jpg|thumb|The [[Saab Viggen]] pioneered the close-coupled canard]]
{{main article|Canard (aeronautics)}}
Through the 1960s, the [[Sweden|Swedish]] aircraft manufacturer [[Saab AB]] developed a close-coupled canard delta configuration, placing a delta foreplane just in front of and above the main delta wing.<ref>{{Citation | last1 = Green | first1 = W | last2 = Swanborough | first2 = G | title = The complete book of fighters | publisher = Salamander | year = 1994 | pages=514 to 516}}.</ref> [[Patent]]ed in 1963, this configuration was flown for the first time on the company's [[Saab 37 Viggen|Viggen]] combat aircraft in 1967. The close coupling modifies the airflow over the wing, most significantly when flying at high angles of attack. In contrast to the classic tail-mounted elevators, the canards add to the total lift as well as stabilising the airflow over the main wing. This enables more extreme manoeuvres, improves low-speed handling and reduces the takeoff run and landing speed. During the 1960s, this configuration was considered to be radical, but Saab's design team judged that it was the optimal approach available for satisfying the conflicting performance demands for the Viggen, which including favourable [[STOL]] performance, supersonic speed, low turbulence sensitivity during low level flight, and efficient lift for subsonic flight.<ref name="saab 60" >[http://saabgroup.com/about-company/history/1960s/ "1960s."] {{Webarchive|url=https://web.archive.org/web/20200629225459/https://saabgroup.com/about-company/history/1960s/ |date=2020-06-29 }} ''Company History'', Saab. Retrieved 6 March 2016.</ref><ref name="bomber 244">Gunston and Gilchrist 1993, p. 244.</ref>

The close-coupled canard has since become common on supersonic fighter aircraft. Notable examples include the multinational [[Eurofighter Typhoon]], France's [[Dassault Rafale]], Saab's own [[Gripen]] (a successor to the Viggen) and Israel's [[IAI Kfir]]. One of the main reasons for its popularity has been the high level of agility in manoeuvring that it is capable of.<ref name="warwick 1260" >Warwick 1980, p. 1260.</ref><ref>Roskam 2002, p. 206.</ref>

===Supersonic transport===
{{main article|Supersonic transport}}
When supersonic transport (SST) aircraft were developed, the tailless ogival delta wing was chosen for both the Anglo-French [[Concorde]] and the Soviet [[Tupolev Tu-144]], the Concorde beginning test flights in 1965 and the Tupolev first flying in 1968. While both Concorde and the Tu-144 prototype featured an [[ogival delta]] configuration, production models of the Tu-144 differed by changing to a [[double delta]] wing.<ref name=gordon>Tupolev Tu-144, Gordon, Komissarov and Rigmant 2015, Schiffer Publishing Ltd, {{ISBN|978-0-7643-4894-5}}</ref> The delta wings required these airliners to adopt a higher [[angle of attack]] at low speeds than conventional aircraft; in the case of Concorde, lift was maintained by allowed the formation of large low pressure vortices over the entire upper wing surface.{{sfn|Orlebar|2004|p=44}} Its typical landing speed was {{convert|170|mph|km/h|0}}, considerably higher than subsonic airliners.{{sfn|Schrader|1989|p=84}} Multiple proposed successors, such as the [[Zero Emission Hyper Sonic Transport]] ZEHST), have reportedly adopted a similar configuration to that Concorde's basic design, thus the Delta wing remains a likely candidate for future supersonic civil endeavours.<ref name="Independent">{{Citation | url = https://www.independent.co.uk/travel/news-and-advice/concordes-successor-revealed-at-paris-air-show-2300191.html | title = Concorde's successor revealed at Paris Air Show | newspaper = [[The Independent]] | date = 20 June 2011 | access-date = 21 June 2011 | archive-date = 22 June 2011 | archive-url = https://web.archive.org/web/20110622035456/http://www.independent.co.uk/travel/news-and-advice/concordes-successor-revealed-at-paris-air-show-2300191.html | url-status = live }}</ref>

===Rogallo flexible wing===
[[File:Birdman MJ-5 0002.jpeg|thumb|This hang glider is a relatively broad-span and lightly swept Rogallo delta]]
{{Main|Rogallo wing}}
During and after WWII, Francis and Gertrude Rogallo developed the idea of a flexible wing which could be collapsed for storage. Francis saw an application in spacecraft recovery and NASA became interested. In 1961, Ryan flew the [[Ryan XV-8|XV-8]], an experimental "flying Jeep" or "fleep". The flexible wing chosen for it was a delta wing; in use, it billowed out into a double-cone profile which gave it aerodynamic stability. Although tested but ultimately never used for spacecraft recovery, this design soon became popular for [[Hang-gliders|hang gliders]] and [[ultra-light aircraft]] and has become known as the Rogallo wing.

==See also==
*[[List of delta-wing aircraft]]
*[[Hermann Behrbohm]]
*[[Bertil Dillner]]
*[[Swept wing]]
*[[Flying wing]]
*[[Tailless aircraft]]

==References==
===Citations===
{{reflist|32em}}

===Bibliography===
{{Refbegin}}
* Allward, Maurice. ''Postwar Military Aircraft: Gloster Javelin''. Ian Allan, 1999. {{ISBN|978-0-711-01323-0}}.
* {{Cite journal | last1 = Bradley | first1 = Robert | year = 2003 | title = The Birth of the Delta Wing| journal = J. Am. Aviation Hist. Soc. }}
* {{cite book | last = Buttler | first = Tony | series= British Secret Projects 1 |title= Jet Fighters since 1950 |edition=2nd | location= Manchester | publisher = Crecy Publishing | date = 2017  | isbn = 978-1-910-80905-1}}
* Gunston, Bill and Peter Gilchrist. ''Jet Bombers: From the Messerschmitt Me 262 to the Stealth B-2''. Osprey, 1993. {{ISBN|1-85532-258-7}}.
* Mason W.H. [http://www.dept.aoe.vt.edu/~mason/Mason_f/ConfigAero.html "Configuration Aerodynamics."] {{Webarchive|url=https://web.archive.org/web/20150914031529/http://www.dept.aoe.vt.edu/~mason/Mason_f/ConfigAero.html |date=2015-09-14 }} AOE 4124, Virginia Tech.
* {{Cite book |author-link=Christopher Orlebar|last=Orlebar|first=Christopher |title=The Concorde Story |location=Oxford, UK |publisher=Osprey Publishing|year=2004 |isbn=978-1-85532-667-5 }}
* Patridge, J. ''The Gloster Javelin 1–6: Number 179.'' Profile Publications, 1967.
* {{Cite book |last=Schrader |first=Richard K |title=Concorde: The Full Story of the Anglo-French SST |location=Kent, UK |publisher=Pictorial Histories Pub. Co.|year=1989 |isbn=978-0-929521-16-9 }}
* Warwick, Graham. [https://www.flightglobal.com/pdfarchive/view/1980/1980%20-%202917.html "Interceptor Viggen."] {{Webarchive|url=https://web.archive.org/web/20160313203725/https://www.flightglobal.com/pdfarchive/view/1980/1980%20-%202917.html |date=2016-03-13 }} ''Flight International'', 27 September 1980. pp.&nbsp;1260–65.
* Roskam, Jan. ''Airplane Design: Layout Design of Cockpit, Fuselage, Wing and Empennage : Cutaways and Inboard Profiles.'' DARcorporation, 2002. {{ISBN|1-8848-8556-X}}.
{{Refend}}

==External links==
{{Commons category|Delta wings}}
{{Wiktionary|delta wing}}
*[http://www.aero.gla.ac.uk/Research/LowSpeedAero/delta.htm Analysis of air flow over delta wings]{{Dead link|date=June 2025 |bot=InternetArchiveBot |fix-attempted=yes }}

[[Category:Aircraft wing design]]
[[Category:Wing configurations]]
[[Category:Delta-wing aircraft| ]]