Airplane Canard used only for its ability to prevent a stall?

Question

Canards stall first,nose drops and prevents the main plane from stalling.
Is that the only reason why canards are used?
And why isnt it used in commercial aircraft?
Does it serve any other purpose?

Answer 1

The canard would stall first only if it is designed that way, with a higher effective angle of incidence, or using an airfoil that stalls at a lower incidence than the main wing.



That 'stall first' characteristic is used for small planes like the Rutan design.

For larger planes, the interest of canard may be:

- that the control surface does not create down lift that the main wing has to compensate

- additional handling capability at high incidence (typically for military airplane)

- natural resistance to deep stall



The reason why it is not used more widely is that:

- in order to benefit the most from the handling, fly-by-wire is usually required, and there are not that many fly-by-wire aircraft yet

- the improved performance due to the deletion of a down force conventional tail can partly be achieved with an uplifting tail surface coupled with fly-by-wire (to restore the reduced static stability), but in any rate, canard would need an altered structural design to support forward mounted horizontal planes

- the presence of a canard may lessen the effectiveness of leading edge slats on the main wing



Anything that deviates for the 'classic' configuration will be viewed as risky and costly to certify (since the authorities lack experience in certifying unconventional airliners) and perhaps also by the flying public. If passengers would not readily fly in an unconventional looking airliners, airlines would be reluctant to buy them. If airlines are reluctant to purchase an airliner model, airframers would be reluctant to invest the $ billions needed to develop it.

There is a lot of technology out there that is not marketed because the management structure views them as a risk of the final result not being accepted.

Answer 2

In addition to the excellent aerodynamic answers, for light GA aircraft the visibility is nice too.



You don't have a wing blocking your view as you turn as is the case with most of the Cessna 1x2 or 1x0 family, and it isn't in the way like it would be looking down if you were in a Piper. Being that "see and avoid" is a key responsibility, I like having the least restricted view possible.



Also, canard aircraft are typically pushers, so the noisy stuff is behind you, making the cockpit quieter. Also, with the engine in the back, the nose can be more aerodynamically efficient and again, a better view.

Answer 3

Airplanes that use a canard are generally more efficient, because a rear mounted horizontal stabilizer usually (but not always) produces a downward force that the wing then has to carry.



The problem with canards is that the loading and C of G is very sensitive, the design of the aircraft is very inflexible to different purposes, and it can create several problems that result from its lack of pitch authority... like requiring higher takeoff and landing speeds.



The only commercial aircraft with canards was the Beech Starship. Due to numerous design compromises, it was no more efficient than standard aircraft. The Piaggio Avanti uses a much more successful hybrid design.