PPRuNe Forums - View Single Post - The Wright brothers just glided in 1903. They flew in 1908.
Old 28th Jun 2014, 19:50
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simplex1
 
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I assume that a lot of the pioneers favoured a canard elevator in part because their machines were marginal. With a canard, if you want to climb, the elevator produces increased lift (if I have got this right, and thinking of early 20th c. circumstances, when they couldn't increase power at will). This looks a lot more logical and efficient than the alternative, and presumably indicates that even the Wrights weren't at first fully aware of how critical controllability, and positive stability, were for successful flight. Does this seem plausible?
Canard configuration is bad and should be avoided
It is not just a simple coincidence that the majority of planes do not have canard wings. Some early inventors and plane builders adopted in 1906, 1907 the canard wings likely under the influence of the noise made by the wright brothers regarding their 1902 glider. Most of them quickly dropped either the canard configuration or the pusher propeller.
Santos-Dumont renounced the canard wings in the beginning of 1907, Bleriot dropped them in spring 1907, even the Voisin brothers finally gave up canards.

Important disadvantages of canard wings:

- "if the canard is controllable and provides pitch control, it cannot be allowed to stall before the wing stalls. In order to accomplish this, normally the travel of the control surface is limited. This noticeably reduces effectiveness in the landing flare, requiring higher approach airspeeds and longer landing distances."
Source: Effect of CG , see also the pictures.

- "Finally, and perhaps most importantly, canard sizing is much more critical than aft tail sizing. By choosing a canard which is somewhat too big or too small the aircraft performance can be severely affected. It is easy to make a very bad canard design."
Source: Canard Advantages and Disadvantages

Last edited by simplex1; 28th Jun 2014 at 20:09.
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