Canard (aeronautics).html



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Canards (blue) on the Saab Viggen

In aeronautics, canard (French for duck) is an airframe configuration of fixed-wing aircraft in which the tailplane is ahead of the main wing, rather than behind them as in conventional aircraft empennage.¹²³

The earliest airplanes, such as the Wright Flyer and the Santos-Dumont 14-bis, due to their tail-first configuration were seen by observers to resemble a flying duck — hence the name.⁴

Classes of canards

The canard wing exists in two classes: the control-canard and the lifting-canard.⁵

Control-canard (yellow) on an IAI Kfir

Rutan Long-EZ, with lifting-canard ahead of the cockpit.

A deflected control-canard on an RAF Typhoon F2

Control-canard

In the control-canard, most of the weight of the aircraft is carried by the main wing and the canard wing is used primarily for longitudinal control during maneuvering. A control-canard mostly operates at zero angle of attack. Combat aircraft that have the canard configuration typically have a control-canard. In combat aircraft, the canard is usually driven by a computerized flight control system.⁵

One benefit obtainable from a control-canard is avoidance of pitchup. An all-moving canard capable of a significant nose-down deflection will protect against pitchup. As a result, the aspect ratio and wing-sweep of the main wing can be optimized without having to guard against pitchup.⁵

Lifting-canard

In the lifting-canard, the weight of the aircraft is always shared between the main wing and the canard wing. A lifting-canard generates an upload, in contrast to a conventional aft-tail which mostly generates a download that must be counteracted by extra lift on the main wing. The lifting-canard configuration is therefore more efficient than a conventional aft-tail from the perspective of induced drag. The lift generated by the canard wing is significant, so in order to minimise induced drag on the canard, it is usually of higher aspect ratio and greater airfoil camber than a control-canard. ⁵

With a lifting-canard, the main wing must be located further aft of the center of gravity range than with a conventional aft tail, and this increases the pitching moment caused by trailing-edge flaps. Aircraft with lifting canards cannot readily be designed with sophisticated trailing-edge flaps.⁵

Examples of canard aircraft

Aircraft that have employed this configuration include:

Gallery

The first powered airplane, the Wright Flyer, used dual, vertically-stacked canards	Eurofighter Typhoon of the Royal Air Force displaying at the Farnborough Airshow, 2006	Dassault Rafale, in service with the French Navy (Marine Nationale) and the French Air Force (Armée de l'Air)	Canards visible on a JAS 39 Gripen at the Farnborough Airshow
Grumman X-29, an experimental aircraft for forward swept wing research	The Rockwell-MBB X-31 Enhanced Fighter Maneuverability Demonstrator Aircraft	Canards (just behind the flight deck) on the XB-70 Valkyrie experimental bomber aircraft	Closeup of a Piaggio P180 Avanti's canards
Mikoyan-Gurevich MiG-8, 1945	The Beechcraft Starship Executive Transport	A Pterodactyl Ascender II+2 showing its canard control surface	Saab 37 Viggen of the Swedish Air Force

References

• Daniel P. Raymer (1989). Aircraft Design: A Conceptual Approach, American Institute of Aeronautics and Astronautics, Inc., Washington, DC. ISBN 0-930403-51-7. 
• R Wilkinson (2001). Aircraft Structures and Systems (2nd edition ed.), MechAero Publishing. 

Notes

See also

• Tandem wing
• Stabilator
• Tailplane

External links

Wikimedia Commons has media related to: Canard Aircraft

• Desktop Aero - A Summary of Canard Advantages and Disadvantages