View source for Canard (aeronautics)

{{Short description|Aircraft configuration in which a small wing is placed in front of the main wing}}
{{Use dmy dates|date=April 2023}}
{{Use British English|date=April 2023}}
[[File:Saab AJS-37 Viggen 37098 52 (SE-DXN) (9256079273).jpg|thumb|A [[Saab 37 Viggen]], the first modern canard aircraft to go into production]]

In [[aeronautics]], a '''canard''' is a [[wing configuration]] in which a small forewing or foreplane is placed forward of the main [[wing]] of a [[fixed-wing aircraft]] or a weapon. The term "canard" may be used to describe the aircraft itself, the [[wing configuration]], or the foreplane.<ref>Wragg, D.; ''Historical Dictionary of Aviation'', History Press (2008), Page 79.</ref><ref name="clancy">Clancy, L. J. (1975). ''Aerodynamics'', Pitman (UK), Halsted (US), 1975. Pages 292-3.</ref><ref name="Crane">{{Citation | last = Crane | first = Dale | title = Dictionary of Aeronautical Terms | edition = 3rd | page = 86 | publisher = Aviation Supplies & Academics | year = 1997 | isbn = 978-1-56027-287-8}}.</ref> Canard wings are also extensively used in [[guided missile]]s and [[smart bomb]]s.<ref>[https://core.ac.uk/download/pdf/36704072.pdf Aerodynamic analysis of a canard missile configuration using ANSYS] Calhoun: The NPS Institutional Archive, December 2011. Retrieved 16 June 2021</ref><ref>[https://ntrs.nasa.gov/api/citations/19830019688/downloads/19830019688.pdf Effect of Tail-Fin Span on Stability and Control Characteristics of a Canard-Controlled Missile at Supersonic Mach Numbers] [[NASA]] Technical paper 2157, June 1983. Retrieved 16 June 2021</ref><ref>[https://fas.org/man/dod-101/sys/smart/lgb.htm Laser Guided Bombs] FAS Military Analysis Network, 12 February 2000. Retrieved 16 June 2021</ref>

The term "canard" arose from the appearance of the [[Santos-Dumont 14-bis]] of 1906, which was said to be reminiscent of a [[duck]] (''canard'' in French) with its neck stretched out in flight.<ref name="c">{{cite book|url=https://books.google.com/books?id=tDmR7DhM_uEC&pg=PA40|title=Contact! : the story of the early aviators|last=Villard|first=Henry Serrano|publisher=Dover Publications|year=2002|isbn=978-0-486-42327-2|location=Mineola, NY|pages=39–53}}</ref>{{Sfn | Burns | 1983}}

Despite the use of a canard surface on the first powered aeroplane, the [[Wright Flyer]] of 1903, canard designs were not built in quantity until the appearance of the [[Saab Viggen]] jet fighter in 1967. The aerodynamics of the canard configuration are complex and require careful analysis.

Rather than use the conventional [[Tailplane|tailplane configuration]] found on most aircraft, an aircraft designer may adopt the canard configuration to reduce the main wing loading, to better control the main wing airflow, or to increase the aircraft's maneuverability, especially at high [[Angle of attack|angles of attack]] or during a [[Stall (fluid mechanics)|stall]].<ref>{{Cite book|last1=Kundu|first1=Ajoy Kumar|title=Conceptual Aircraft Design: An Industrial Approach|last2=Price|first2=Mark A.|last3=Riordan|first3=David|publisher=John Wiley and Sons|date=Apr 8, 2019|pages=237}}</ref> Canard foreplanes, whether used in a canard or [[Three-surface aircraft|three-surface]] configuration, have important consequences for the aircraft's longitudinal equilibrium, static and dynamic stability characteristics.[[File:Santos - Nov12 1906 xcerpt.JPG|thumb|The 1906 [[Santos-Dumont 14-bis]]]]

==History==
[[File:Kitty hawk gross.jpg|thumb|The [[Wright Flyer]] of 1903 was a canard biplane]]

===Pioneer years===

The [[Wright Brothers]] began experimenting with the foreplane configuration around 1900. Their first kite included a front surface for pitch control and they adopted this configuration for their first [[Wright Flyer|Flyer]]. They were suspicious of the aft tail because [[Otto Lilienthal]] had been killed in a glider with one. The Wrights realised that a foreplane would tend to destabilise an aeroplane but expected it to be a better control surface, in addition to being visible to the pilot in flight.<ref>{{Cite journal|url = http://authors.library.caltech.edu/11239/1/CULaiaaj03.pdf|title = The Wright Brothers: First Aeronautical Engineers and Test Pilots|last = Culick|first = F.E.C.|date = 2003|journal = AIAA Journal|volume = 41|issue = 6|pages = 985–1006|doi = 10.2514/2.2046|access-date = 2015-08-08|bibcode = 2003AIAAJ..41..985C |citeseerx = 10.1.1.579.7665}}</ref> They believed it impossible to provide both control and stability in a single design, and opted for control.

Many pioneers initially followed the Wrights' lead.<ref>Jerram, Michael E. ''Incredible Flying Machines''. Marshall Cavendish, 1980. p.59.</ref> For example, the [[Santos-Dumont 14-bis]] aeroplane of 1906 had no "tail", but a [[box kite]]-like set of control surfaces in the front, pivoting on a [[universal joint]] on the fuselage's extreme nose. This was intended to provide both yaw and pitch control. The [[Fabre Hydravion]] of 1910 was the first floatplane to fly and had a foreplane.

But canard behaviour was not properly understood and other European pioneers—among them, [[Louis Blériot]]—were establishing the tailplane as the safer and more "conventional" design. Some, including the Wrights, experimented with both fore and aft planes on the same aircraft, now known as the [[three surface aircraft|three surface]] configuration.

After 1911, few canard types would be produced for many decades. In 1914 W.E. Evans commented that "the Canard type model has practically received its death-blow so far as scientific models are concerned."<ref>{{Citation | title = Flight | date = 14 March 1914 | page = 286 | url = http://www.flightglobal.com/pdfarchive/view/1914/1914%20-%200286.html | publisher = Flight global}}.</ref>

===1914 to 1945===
[[File:Curtiss XP-55 Ascender in flight 061024-F-1234P-007.jpg|thumb| [[Curtiss-Wright XP-55 Ascender]] ]]
[[File:Kyushu SHindenjmodelo.JPG|thumb|The Kyūshū J7W1 ''Shinden'' (scale model)]]
Experiments continued sporadically for several decades.

In 1917, de Bruyère constructed his [[De Bruyère C 1|C 1]] biplane fighter, having a canard foreplane and rear-mounted pusher propeller. The C 1 was a failure.<ref>{{Citation | last1 = Green | first1 = W | last2 = Swanborough | first2 = G | title = The complete book of fighters | publisher = Salamander | year = 1994 | page = 163}}.</ref> <!-- Saved this bit for moving to a new article when created: The C.1 featured a single (monoplane) canard foreplane with both dorsal and ventral tail fins behind which was the rear-mounted pusher propeller. The tip sections of the upper wings were movable and acted as ailerons. The C.1 rolled over and crashed on its first flight. -->

First flown in 1927, the experimental [[Focke-Wulf F 19]] "Ente" (duck) was more successful.  Two examples were built and one of them continued flying until 1931.

Immediately before and during World War II, several experimental canard fighters were flown, including the [[Ambrosini SS.4]], [[Curtiss-Wright XP-55 Ascender]] and [[Kyushu J7W Shinden|Kyūshū J7W1 ''Shinden'']]. These were attempts at using the canard configuration to give advantages in areas such as performance, armament disposition or pilot view. Ultimately, no production aircraft were completed. The Shinden was ordered into production "off the drawing board"{{Clarify|reason=not clear what an "off the drawing board" order would be|date=February 2022}} but only prototypes had flown by the time the war ended.

In 1945 in Europe, what may have been the first canard designed and flown in the [[Soviet Union]] appeared as a test aircraft, the experimental [[Mikoyan-Gurevich MiG-8]] ''Utka'' (Russian for "duck"), a lightweight propeller aircraft. It was noted for its docile slow-speed handling characteristics{{Citation needed|date=February 2022}} and flew for some years, being used as a testbed during development of the swept wing of the (conventional layout) [[Mikoyan-Gurevich MiG-15|MiG-15]] jet fighter.

===Canard revival===
[[File:North American XB-70 above runway ECN-792.jpg|thumb|[[XB-70 Valkyrie]] experimental bomber]]

With the arrival of the [[jet age]] and supersonic flight, American designers, notably [[North American Aviation]], began to experiment with supersonic canard delta designs, with some such as the [[North American XB-70 Valkyrie]] and the Soviet equivalent [[Sukhoi T-4]] flying in prototype form. But the stability and control problems encountered prevented widespread adoption.<ref name="saab" />

In 1963 the Swedish company Saab patented a delta-winged design which overcame the earlier problems, in what has become known as the close-coupled canard.<ref name="saab">''Delta wing canard aircraft'', US Patent [https://patents.google.com/patent/US3188022 US3188022 A].</ref><ref name="anderson21">Anderson, S.B.; [https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19870013196.pdf A Look at Handling Qualities of Canard Configurations], NASA Technical Memorimdum 88354, 1986, page 21.</ref> It was built as the [[Saab 37 Viggen]] and in 1967 became the first modern canard aircraft to enter production. The success of this aircraft spurred many designers, and canard surfaces sprouted on a number of types derived from the popular [[Dassault Mirage]] delta-winged jet fighter. These included variants of the French [[Dassault Mirage III]], Israeli [[IAI Kfir]] and South African [[Atlas Cheetah]]. The close-coupled canard delta remains a popular configuration for combat aircraft.

The Viggen also inspired the American [[Burt Rutan]] to create a two-seater homebuilt canard delta design, accordingly named [[Rutan VariViggen|VariViggen]] and flown in 1972. Rutan then abandoned the delta wing as unsuited to such light aircraft. His next two canard designs, the [[Rutan VariEze|VariEze]] and [[Rutan Long-EZ|Long-EZ]] had longer-span swept wings. These designs were not only successful and built in large numbers but were radically different from anything seen before.<ref name=":0">{{Citation | first = Daroll | last = Stinton | title = The design of the aeroplane | quote = Rutan canards wrought a change in thinking which might have a profound influence in future}}.</ref> Rutan's ideas soon spread to other designers. From the 1980s they found favour in the executive market with the appearance of types such as the [[OMAC Laser 300]], [[Avtek 400]] and [[Beechcraft Starship|Beech Starship]].
[[File:Su-30SM (36349482501).jpg|thumb|[[Sukhoi Su-30|Sukhoi Su-30SM]] with canard.]]

===Computer control===
[[File:Gripen - RIAT 2009 (3793317200).jpg|thumb|Canards visible on a [[JAS 39 Gripen]]]]
[[File:Sukhoi_Su-47_Berkut_(S-37)_in_2001.jpg|thumb|Canards on a [[Su-47]]]]

Static canard designs can have complex interactions in airflow between the canard and the main wing, leading to issues with stability and behaviour in the stall.<ref>{{Cite journal|last=Anderson|first=Seth B.|date=September 1986|title=A look at Handling Qualities of Canard Configurations|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19870013196.pdf|journal=NASA Technical Memorandum 88354|pages=4–5}}</ref> This limits their applicability. The development of fly-by-wire and artificial stability towards the end of the century opened the way for computerized controls to begin turning these complex effects from stability concerns into maneuverability advantages.<ref name=":0" />

This approach produced a new generation of military canard designs.  The [[Dassault Rafale]] multirole fighter first flew in 1986, followed by the [[Saab JAS 39 Gripen|Saab Gripen]] (first to enter service) in 1988, and the [[Eurofighter Typhoon]] in 1994. These three types and related design studies are sometimes referred to as the '''euro-canards''' or '''eurocanards'''.<ref>{{Cite web | date = 2013-11-15 |url= https://www.ainonline.com/aviation-news/defense/2013-11-15/swiss-battle-could-be-euro-canard-turning-point|title=Swiss Battle Could Be Euro-Canard Turning Point |first= Chris|last=Pocock|website= Aviation International News}}</ref><ref>{{Cite web|url=https://www.flightglobal.com/jast-hover-tests-to-start-in-june/15919.article|title=JAST hover tests to start in June|website=Flight Global}}</ref><ref>{{Cite web|url=https://aviationweek.com/defense-space/aircraft-propulsion/future-fighter-investment-keeping-eurocanards-competitive|title=Future Fighter Investment Is Keeping Eurocanards Competitive &#124; Aviation Week Network|website=aviationweek.com}}</ref> The Chinese [[Chengdu J-10]] appeared in 1998.

==Basic principles ==
[[File:Sukhoi_Su-34_at_the_MAKS-2013_(03).jpg|thumb|right|[[Su-34]], with canards ]]
Like any wing surface, a canard contributes to the lift, (in)stability and trim of an aircraft, and may also be used for flight control.

===Lift===
[[File:rutan.long-EZ.g-wily.arp.jpg|thumb|right|[[Rutan Long-EZ]], with high-aspect-ratio lifting canard and suspended luggage pods]]
Where the canard surface contributes lift, the weight of the aircraft is shared between the wing and the canard. It has been described as an extreme conventional configuration but with a small highly loaded wing and an enormous lifting tail which enables the centre of mass to be very far aft relative to the front surface.<ref name=Drela>{{Citation | url = http://www.rcuniverse.com/forum/m_3441894/mpage_2/printable.htm | title = Canard description | first = Mark, Aero-astro professor, MIT | last = Drela | publisher = RC universe | type = forum | url-status = dead | archive-url = https://archive.today/20130630052932/http://www.rcuniverse.com/forum/m_3441894/mpage_2/printable.htm | archive-date = 2013-06-30 }}.</ref>

A lifting canard generates an upload, in contrast to a conventional aft-tail which sometimes generates negative lift that must be counteracted by extra lift on the main wing. As the canard lift adds to the overall lift capability of the aircraft, this may appear to favour the canard layout. In particular, at takeoff the wing is most heavily loaded and where a conventional tail exerts a downforce worsening the load, a canard exerts an upward force relieving the load. This allows a smaller main wing.

However, the foreplane also creates a [[downwash]], which may affect the wing lift distribution favourably or unfavourably, so the differences in overall lift and [[Lift-induced drag|induced drag]] are not obvious and they depend on the details of the design.<ref name= Canards /><ref name= Drela/><ref name= CanardProCon>{{Citation | url = http://docs.desktop.aero/appliedaero/configuration/canardProCon.html | publisher = Desktop Aero | title = A Summary of Canard Advantages and Disadvantages | access-date = 2015-10-06 | archive-url = https://web.archive.org/web/20150503195149/http://docs.desktop.aero/appliedaero/configuration/canardProCon.html | archive-date = 2015-05-03 | url-status = dead }}.</ref>

With a lifting canard, the main wing must be located further aft of the centre of gravity than a conventional wing, increasing the downward pitching moment caused by the deflection of its [[Flap (aircraft)|trailing-edge flaps]].<ref name=raymer1999>{{cite book|last1=Raymer|first1=Daniel P.|title=Aircraft Design: A Conceptual Approach|date=1999|publisher=AIAA|isbn=978-1-56347-281-7|edition=3}}</ref>

===Control===
[[File:RAF Eurofighter Typhoon cockpit.jpg|thumb|The control canard on an [[RAF]] [[Eurofighter Typhoon|Typhoon]] in flight]]
Pitch control in a canard type may be achieved either by the canard surface, as on the control-canard or in the same way as a [[tailless aircraft]], by control surfaces at the rear of the main wing, as on the Saab Viggen.

In a control-canard design, most of the weight of the aircraft is carried by the wing and the canard is used primarily for pitch control during maneuvering. A pure control-canard operates only as a control surface and is nominally at zero [[angle of attack]] and carrying no load in normal flight. Modern combat aircraft of canard configuration typically have a control-canard driven by a [[Fly-by-wire|computerized flight control system]].<ref name=raymer1999/>

Canards with little or no loading (i.e. control-canards) may be used to intentionally destabilize some combat aircraft in order to make them more manoeuvrable. The electronic flight control system uses the pitch control function of the canard foreplane to create artificial static and dynamic stability.<ref name=Canards>{{Harvnb | Neblett | Metheny | Leifsson | 2003}}.</ref><ref name =CanardProCon />

A benefit obtainable from a control-canard is the correction of [[pitch-up]] during a wingtip stall.  An all-moving canard capable of a significant nose-down deflection can be used to counteract the pitch-up due to the tip stall.  As a result, the [[aspect ratio]] and sweep of the wing can be optimized without having to guard against pitch-up.<ref name=raymer1999/> A highly loaded lifting canard does not have sufficient spare lift capacity to provide this protection.{{Citation needed|date=December 2015}}<ref>{{Cite book|last=Gudmondsson|first=Snorri|title=General Aviation Aircraft Design: Applied Methods and Procedures|publisher=Elsevier Inc.|date=September 3, 2013}}</ref>

===Stability===
[[File:PterodactylAscenderII-B202.jpg|thumb|[[Pterodactyl Ascender II+2]] with stabilizing canard]]
[[File:Sukhoi_Su-33_77_RED_(30268117476).jpg|thumb|[[Su-33]]s with canard]]

A canard foreplane may be used as a [[horizontal stabilizer]], whether stability is achieved statically<ref>Garrison (2002), page 85; "the stabilizer in the front...  This is the function of the stabilizer.  If it's in the back it typically pushes downward, and if it's in the front it lifts upward."</ref><ref name = "benson-apf">{{citation | editor-last = Benson | editor-first = T | title = Airplane parts and functions | work = Beginner's Guide to Aeronautics | publisher = NASA Glenn Research Center | url = http://www.grc.nasa.gov/WWW/K-12/airplane/airplane.html | quote = On the Wright brother's first aircraft, the horizontal stabilizer was placed in front of the wings. | access-date = 30 July 2013 | archive-date = 31 May 2022 | archive-url = https://web.archive.org/web/20220531090450/https://www.grc.nasa.gov/www/k-12/airplane/airplane.html | url-status = dead }}</ref><ref name= "US6064923A">{{Citation | place = US | type = patent | url = https://patents.google.com/patent/US6064923 | id = 6064923 A | title = Aircraft with reduced wing structure loading | quote = ...a front stabilizer, generally known as a canard stabilizer…}}</ref> or artificially (fly-by-wire).<ref>{{Citation | quote = The X-29... while its canards—horizontal stabilizers to control pitch—were in front of the wings instead of on the tail | url = http://www.nasa.gov/centers/dryden/news/FactSheets/FS-008-DFRC.html | publisher = Nasa | place = Dryden | type = fact sheet | id = FS-008-DFRC | title = X-29| date = 9 September 2015 }}.</ref>

Being placed ahead of the centre of gravity, a canard foreplane acts directly to reduce [[longitudinal static stability]] (stability in pitch). The first aeroplane to achieve controlled, powered flight, the [[Wright Flyer]], was conceived as a control-canard<ref>{{Citation | last = Culick | title = AIAA-2001-3385 | quote = Consistently with ignoring the condition of zero net (pitch) moment, the Wrights assumed that in equilibrium the canard carried no load and served only as a control device.}}</ref> but in effect was also an unstable lifting canard.<ref>{{Cite journal|id=TM 88354|title=A look at handling qualities of canard configurations|journal=Journal of Guidance, Control, and Dynamics|volume=10|issue=2|page=8|quote=...the Flyer was highly unstable... The lateral/directional stability and control of the Flyer were marginal|bibcode = 1987JGCD...10..129A|last1=Anderson|first1=Seth B|year=1987|doi=10.2514/3.20194|hdl=2060/19870013196|hdl-access=free}}.</ref> At that time the Wright brothers believed that instability was a requirement to make an aeroplane controllable. They did not know how to make a tailplane unstable, so they chose a canard control surface for this reason.

Nevertheless, a canard stabiliser may be added to an otherwise unstable design to obtain overall static pitch stability.<ref>Garrison (2002), page 85; "Because the center of gravity is not sitting right on top of the center of lift, but is ahead of it, the aircraft would tip over forard if some balancing force were not provided. This is the function of the stabilizer."</ref> To achieve this stability, the change in canard [[lift coefficient]] with [[angle of attack]] (lift coefficient slope) should be less than that for the main plane.<ref name = "Sherwin">{{Cite book|last=Sherwin|first=Keith|title=Man powered flight|edition=rev reprint|page=131|publisher=Model & Allied Publications|year=1975|isbn=978-0-85242-436-0}}.</ref> A number of factors affect this characteristic.<ref name=raymer1999/> For example, seven years after the Wrights' first flight, the [[ASL Valkyrie]] adopted the canard position in order to make the aeroplane stable and safe.

For most [[airfoil]]s, [[lift slope]] decreases at high lift coefficients. Therefore, the most common way in which pitch stability can be achieved is to increase the lift coefficient (so the wing loading) of the canard. This tends to increase the [[Induced drag|lift-induced drag]] of the foreplane, which may be given a high [[Aspect ratio (wing)|aspect ratio]] in order to limit drag.<ref name=Sherwin/> Such a canard airfoil has a greater airfoil [[camber (aerodynamics)|camber]] than the wing.

Another possibility is to decrease the aspect ratio of the canard,<ref>{{Citation | last = Hoerner | title = Fluid Dynamic Lift | pages = 11–30 | chapter = Aspect ratio}}.</ref> with again more lift-induced drag and possibly a higher [[Stall (flight)|stall]] angle than the wing.<ref>{{Citation|title=Lift-induced drag|date=2019-09-25|url=https://en.wikipedia.org/w/index.php?title=Lift-induced_drag&oldid=917751056|work=Wikipedia|language=en|access-date=2020-03-17}}</ref>

A design approach used by [[Burt Rutan]] is a high aspect ratio canard with higher lift coefficient (the wing loading of the canard is between 1.6 and 2 times the wing one) and a canard airfoil whose lift coefficient slope is non-linear (nearly flat) between 14° and 24°.<ref name="ReferenceA">{{Citation | publisher = Nasa | id = TP 2382 | title = VariEze Wind Tunnel Investigation}}.</ref>

Another stabilisation parameter is the power effect. In case of canard [[pusher propeller]]: "the power-induced flow clean up of the wing trailing edge" <ref name="ReferenceA"/> increases the wing lift coefficient slope (see above). Conversely, a propeller located ahead of the canard (increasing the lift slope of the canard) has a strong destabilising effect.<ref>{{Citation | title = Tandem aircraft PAT-1 | publisher = Nasa | id = TM 88354}}.</ref>

===Trim===
[[File:Aeroflot_Tupolev_Tu-144_1977_Volpati-1.jpg|thumb|[[Tupolev Tu-144]] with its retractable moustache canards deployed and nose [[Droop nose (aeronautics)|drooped]]]]

A canard foreplane may be used to trim an aeroplane in pitch, just as a tail plane can. The trimming force in pitch is also a lifting force, and the greater it is, the greater the associated [[induced drag]], known as [[trim drag]]. However, where a conventional tail typically pushed down with a negative trimming force which makes the wing work harder, a canard pushes up so the wing works less hard. This actually reduces the net drag, resulting in negative trim drag.<ref name="clancy"/>

The use of landing flaps on the main wing causes a large trim change, which must be compensated for. The [[Saab Viggen]] has flaps on its canard surface which may be deployed simultaneously with the main flaps. The [[Beech Starship]] uses variable-sweep foreplanes to trim the position of the lift force.

When the main wing is most loaded, at takeoff, to rotate the nose up a conventional tailplane typically pushes down while a foreplane lifts up. In order to maintain trim the main wing on a canard design must therefore be located further aft relative to the centre of gravity than on the equivalent conventional design.

==Applications==

===Close coupling===
A close-coupled canard has been shown to benefit a supersonic [[delta wing]] design which gains lift in both [[transonic]] flight (such as for [[supercruise]]) and also in low speed flight (such as take offs and landings).<ref name="NASA-TM-88354">{{Citation|last=Anderson|first=Seth B|title=A Look at Handling Qualities of Canard Configurations|date=1 September 1986|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19870013196_1987013196.pdf|journal=Journal of Guidance, Control, and Dynamics|volume=10|issue=2|page=16|bibcode=1987JGCD...10..129A|doi=10.2514/3.20194|id=TM-88354|quote=Incorporating roll control on the canard is basically less efficient because of an adverse downwash influence on the main wing opposing the canard rolling-moment input.|hdl=2060/19870013196|hdl-access=free}}</ref>[[File:Rafale (7986533137).jpg|thumb|[[Dassault Rafale|A Dassault Rafale]] in high angle-of-attack flight]]
In the close-coupled delta wing canard, the foreplane is located just above and forward of the wing. The vortices generated by a delta-shaped foreplane flow back past the main wing and interact with its own vortices. Because these are critical for lift, a badly-placed foreplane can cause severe problems. By bringing the foreplane close to the wing and just above it in a close-coupled arrangement, the interactions can be made beneficial, actually helping to solve other problems too.<ref name="saab" /> For example, at high angles of attack (and therefore typically at low speeds) the canard surface directs airflow downward over the wing, reducing turbulence which results in reduced drag and increased lift.<ref name="Sageaction">{{cite web | url = http://www.sageaction.com/aircraft_testing1.htm#JetAircraft | title = Jet Aircraft – Effect of a close-coupled canard on a swept wing | type = Abstract | website = SAI Research Report | id = 7501 | access-date = 2009-08-25 | publisher = Sage Action | year = 2009 | archive-url = https://web.archive.org/web/20150219214246/http://sageaction.com/aircraft_testing1.htm#JetAircraft | archive-date = 2015-02-19 | url-status = dead }}</ref> Typically the foreplane creates a vortex which attaches to the upper surface of the wing, stabilising and re-energising the airflow over the wing and delaying or preventing the stall.{{Citation needed|date=December 2015}}<ref>{{Cite book|title=NASA Conference Publication, Issues 2-3|publisher=Scientific and Technical Information Office, National Aeronautics and Space Administration|year=1977|pages=1–2}}</ref>

The canard foreplane may be fixed as on the [[IAI Kfir]], have landing flaps as on the [[Saab Viggen]], or be moveable and also act as a control-canard during normal flight as on the [[Saab Gripen]].

===Free-floating canard===
A free-floating canard pivots so that the whole surface can rotate freely to change its [[angle of incidence (aerodynamics)|angle of incidence]] to the fuselage without pilot input. In normal flight, the air pressure distribution maintains its [[angle of attack]] to the airflow, and therefore also the [[lift coefficient]] it generates, to a constant amount. A free-floating mechanism may increase [[Longitudinal static stability|static stability]] and provide safe recovery from high [[angle of attack]] evolutions.<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=2011-05-17 }}.</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 = 2014-11-27 }}.</ref> The first [[Curtiss XP-55 Ascender]] was initially fitted with a small free-floating canard lacking sufficient authority. Even on subsequent prototypes fitted with larger surfaces, "the stall was quite an experience".<ref>Jones, Lloyd S.; ''U.S. Fighters: ''Army - Air Force 1925 to 1980s'', Aero, pp.139-41.</ref> Secondary movable surfaces may be added to the free-floating canard, allowing pilot input to affect the generated lift, thus providing pitch control and/or trim adjustment.

===Variable geometry===
[[File:NASA-2000Starship.jpg|thumb|right|The [[Beechcraft Starship]] has variable-sweep foreplanes.]]
The [[Beechcraft Starship]] has a variable-sweep canard surface. The sweep is varied in flight by swinging the foreplanes forward to increase their effectiveness and so trim out the nose-down pitching effect caused by the wing flaps when deployed.<ref>{{Citation | last = Roskam | first = J | title = Airplane Design: Preliminary Configuration Design and Integration of the Propulsion System | publisher = Design Analysis & Research | year = 1989 | isbn = 978-1-884885-43-3 | page = 82}}.</ref>

A '''moustache''' is a small, high [[Aspect ratio (aeronautics)|aspect ratio]] foreplane which is deployed for low-speed flight in order to improve handling at high angles of attack such as during takeoff and landing. It is retracted at high speed in order to avoid the [[wave drag]] penalty of a canard design. It was first seen on the [[Dassault Mirage III#Derivatives|Dassault Milan]] and later on the [[Tupolev Tu-144]]. NASA has also investigated a one-piece [[slewed wing|slewed]] equivalent called the conformably stowable canard,<ref>{{Cite web|url=https://www.techbriefs.com/component/content/article/tb/supplements/mctb/briefs/29542|title=Conformably Stowable Canard|last=Group|first=Techbriefs Media|website=www.techbriefs.com|date=February 2001 |language=en|access-date=2020-03-17}}</ref> where as the surface is stowed one side sweeps backwards and the other forwards.<ref>{{Citation | url = http://www.techbriefs.com/index.php?option=com_staticxt&staticfile=/Briefs/Feb01/ARC14122.html | title = Conformably Stowable Canard | publisher = Ames Research Center | type = tech brief | url-status = dead | archive-url = https://archive.today/20120915102903/http://www.techbriefs.com/index.php?option=com_staticxt&staticfile=/Briefs/Feb01/ARC14122.html | archive-date = 2012-09-15 }}.</ref>

===Ride control===
[[File:A B-1B Lancer with a Sniper pod.jpeg|thumb|[[Rockwell B-1 Lancer|B-1B Lancer]] showing left hand ride-control vane at nose]]

The [[Rockwell B-1 Lancer]] has small canard vanes or fins on either side of the forward fuselage that form part of an active damping system that reduces aerodynamic buffeting during high-speed, low altitude flight. Such buffeting would otherwise cause crew fatigue and reduce airframe life during prolonged flights.<ref>{{Citation | last = Jones | title = US Bombers | newspaper = Aero | year = 1974 | quote = canard vanes}}.</ref><ref>{{Citation | newspaper = Flight | title = B-1 Roll-out | year = 1974 | quote = canard fins for ride control}}.</ref>

===Stealth===

Canard aircraft can potentially have poor [[Stealth aircraft|stealth]] characteristics because they present large angular surfaces that tend to reflect [[radar]] signals forwards.<ref name=Canards />{{Page needed |date=March 2020}}<ref>{{Citation | last = Sweetman | first = William 'Bill' | url = https://books.google.com/books?id=eeWcitAiSBUC&pg=PA104 | title = Top Gun | journal = [[Popular Science]] |date=June 1997 | page = 104}}.</ref>  The [[Eurofighter Typhoon]] uses software control of its canards in order to reduce its effective [[radar cross section]].<ref>[https://translate.google.com/translate?u=http%3A%2F%2Feurofighter.airpower.at%2Ffaq.htm&langpair=de%7Cen&hl=en&ie=UTF-8 "FAQ Eurofighter (translation)."] Retrieved 29 November 2009.</ref><ref>[https://translate.google.com/translate?u=http%3A%2F%2Fwww.airpower.at%2Fforum%2Fviewtopic.php%3Ft%3D2629&langpair=de%7Cen&hl=en&ie=UTF-8  "Austrian Eurofighter committee of inquiry]: [[Brigadier]] Dipl.Ing.Knoll about Eurofighter and Stealth, pp. 76–77. (English translation)" ''Google''. Retrieved 28 November 2009.</ref>

Canards have nevertheless been incorporated in some later stealth aircraft studies such as an early mock-up of Lockheed Martin's [[Joint Strike Fighter program|Joint Advanced Strike Technology (JAST)]] contender<ref>{{Citation | last = Sweetman | first = William 'Bill' | url = http://www.aviationweek.com/aw/blogs/defense/index.jsp?plckController=Blog&plckScript=blogScript&plckElementId=blogDest&plckBlogPage=BlogViewPost&plckPostId=Blog%3A27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3A5c50cb01-bdd0-41cc-b216-fdc89354eb19 | title = From JAST To J-20 | newspaper = Aviation Week | date = 14 January 2011}}.</ref><ref name = "Lockheed Stealth">{{cite book |last=Sweetman |first=William 'Bill' |title=Lockheed Stealth |url=https://books.google.com/books?id=q06Jw1lgcF8C&pg=PA124 |year=2005 |publisher=Zenith Press |isbn=978-0-7603-1940-6 |pages=122–24 [124] }}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> and the [[McDonnell Douglas X-36]] research prototype.<ref>[http://www.designnews.com/document.asp?doc_id=220162&dfpPParams=ind_182,industry_aero,aid_220162&dfpLayout=article "Agility+Stealth = X-36: formula for an advanced fighter "] {{Webarchive|url=https://web.archive.org/web/20140223001051/http://www.designnews.com/document.asp?doc_id=220162&dfpPParams=ind_182,industry_aero,aid_220162&dfpLayout=article |date=2014-02-23 }} ''Design News'' 14 January 2013</ref> The [[Chengdu J-20]] [[Fifth-generation fighter]] uses canards in the belief that they offer the optimal balance of stealth vs. aerodynamics.<ref>{{Cite web|url=https://nationalinterest.org/blog/reboot/how-stealthy-chinas-j-20-fighter-jet-195910|title=How Stealthy is China's J-20 Fighter Jet?|first=Sebastien|last=Roblin|date=9 November 2021|website=The National Interest}}</ref> Some question whether this compromises its stealth characteristics.<ref>{{Cite web|url=https://mikoyanmig29.wixsite.com/chengdu-j-20/stealth|title=Stealth|website=chengdu-j-20}}</ref><ref>{{Cite web|url=https://airpowerasia.com/2020/08/15/chengdu-j-20-overhyped-or-reality-a-comprehensive-story/|title=Chengdu J-20 Overhyped or Reality – A Comprehensive Story|date=15 August 2020}}</ref><ref>{{Cite web|url=https://www.businessinsider.com/china-j20-russia-su57-arent-quite-5th-generation-fighter-jets-2023-2|title=Why China's and Russia's 5th-generation stealth jets don't quite live up to the hype, according to a former US Navy pilot|first=Peter|last=Suciu|website=Business Insider}}</ref>

==See also==
* [[List of canard aircraft]]
* [[Tandem wing]]
* [[Index of aviation articles]]

==References==

===Citations===
{{Reflist}}

===Bibliography===
* {{Citation |first=BRA |last=Burns |title=Were the Wrights Right? |newspaper=[[Air International]] |date=December 1983}}.
* {{Citation |first=BRA |last=Burns |author-mask=5 |url=http://www.flightglobal.com/pdfarchive/view/1985/1985%20-%200561.html |title=Canards: Design with Care |newspaper=[[Flight International]] |date=23 February 1985 |pages=19–21}}.
* {{Citation | last1 = Neblett | first1 = Evan | last2 = Metheny | first2 = Michael 'Mike' | last3 = Leifsson | first3 = Leifur Thor | url = http://www.aoe.vt.edu/~mason/Mason_f/canardsS03.pdf | title = Canards | work = AOE 4124 Class notes | publisher = Department of Aerospace and Ocean Engineering, Virginia Tech | date = 17 March 2003 | url-status = dead | archive-url = https://web.archive.org/web/20080227123111/http://www.aoe.vt.edu/~mason/Mason_f/canardsS03.pdf | archive-date = 27 February 2008 }}.
*{{Citation |last=Garrison |first=P |url=https://books.google.com/books?id=kZcn7cMVfZcC&q=canard+stabilizer&pg=PA85 |title=Three's Company |newspaper=[[Flying (magazine)|Flying]] |volume=129 |issue=12 |date=December 2002 |pages=85–86}}
*{{Cite book |last=Raymer |first=Daniel P. |url=https://archive.org/details/aircraftdesignco0000raym |title=Aircraft Design: A Conceptual Approach |publisher=[[AIAA]] |year=1992 |isbn=9780930403515 |edition=2nd |location=Washington |oclc=0930403517 |url-access=registration}}

==Further reading==
* {{Citation |last1=Abzug |oclc=829704722 |last2=Larrabee |title=Airplane Stability and Control |publisher=Cambridge University Press |isbn=9781107321427 |year=2002}}.
* {{Citation | last1 = Gambu | first1 = J | first2 = J | last2 = Perard | title = Saab 37 Viggen | newspaper = Aviation International | issue = 602 |date=Jan 1973 | pages = 29–40}}.
* {{Citation | last = Lennon | first = Andy | title = Canard : a revolution in flight | publisher = Aviation | year = 1984}}.
* {{Citation | last = Rollo | first = Vera Foster | title = Burt Rutan Reinventing the Airplane | publisher = Maryland Historical Press | year = 1991}}.
* {{cite book | last = Wilkinson| first = R | title= Aircraft Structures and Systems| edition=2nd |publisher= MechAero Publishing | year=2001}}
*{{citation |author1=Selberg, Bruce P  |author2=Cronin, Donald L| title= Aerodynamic-Structural Study of Canard Wing, Dual Wing, and Conventional Wing Systems for General Aviation Applications. University of Missouri-Rolla. Contract Report 172529| publisher= National Aeronautics and Space Administration}} [https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19850008520.pdf Aerodynamic-structural study of canard wing, dual wing, and conventional wing systems for general aviation applications]

==External links==
{{Commons category|Canard wings}}

{{Aircraft components}}
{{Authority control}}

{{DEFAULTSORT:Canard (Aeronautics)}}
[[Category:Aircraft aerodynamics]]
[[Category:Aircraft components]]
[[Category:Wing configurations]]
[[Category:Canard aircraft| ]]
[[Category:Aircraft wing design]]