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Old 09-16-2003 | 12:51 PM
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Rotaryphile
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Joined: Feb 2002
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From: Fredericton, NB, CANADA
Default RE: canard dymanics

I agree 100% with Jack Hyde. Canards have virtually no aerodynamic advantage, as far as I can determine, over the normal layout, and in addition, they have some serious practical shortcomings. Some people, whom I believe to have been a little misguided, seem to think that they will not stall. This thinking is based on having the tail stall before the wing, causing the nose to lower, and thus reducing the angle of attack of the wing, preventing it from stalling. The trouble with this is that if the wing cannot, at least, approach stall, landing and takeoff airspeed will be increased accordingly.

A airplane with the normal, tail-behind, layout can also be made virtually stall-proof simply by locating the CG well forward, and limiting elevator authority. This is a very common setup for R/C trainers, and is totally unsuited to serious aerobatics.

If you set up a canard airplane to have sufficient control authority to stall the wing, and use an aerobatic CG location, they perform almost exactly the same as normal airplanes. I built a small canard glider, as a research airplane for a canard pattern ship that I was designing, and found that it would spin and snap roll exactly the same as a normal airplane. I never built the pattern ship, because I realized that with so much weight so far rearward, it would break up very badly in a crash that would result in little damage to a normal (tractor) layout airplane. (If you are going to fly, you are going to crash - the only unknown is when.)

The only reason that I can see to build a canard is to get something that looks different. All other characteristics are, at best, no better, with the possible exception of knife-edge, which may be considerably better than with a tractor layout, since the center of lateral area tends to be closer to the CG.