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Old Mar 08, 2011, 05:36 PM
canard addict is offline
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John 235
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Charles, Thats great news! It sure sounds like you have it sorted. From what you wrote it sounds like the symmetrical airfoil on the canard is working well for you - especially for inverted flight. I know you moved the CG further back for the Duck 2. That unloads the canard wing slightly, but I was wondering if that would translate into a noticably lower stall speed.

I am really looking forard to the video. I think you will have a challenge to put on a better show than the video of the first Duck. I hope you don't mind me reposting it here, because I think its really good viewing.
John, Sorry for the slow response. I appreciate your interest and challenging questions. It was fun to see the video again and I have contacted the same gentleman to see if he will do a rerun. I was sold on the high lift flat bottom airfoils for years and noted their stall characteristics and inability to do things such as inverted flight and outside loops. The symmetrical airfoils seem so smooth for models that it makes me wonder what purpose that anything in between the two styles would serve. I want to stay with the tear drop style a bit longer just for fun. The speed of the model can be adjusted with drag from thin to thick versions. Regarding the performance with fore vs aft CG, I found that with forward CG the nose of the Duck wanted to droop which could not be fixed well with UP trim. The landings were hard to the point of bending the landing gears. I feared that the canard area should have been increased but by moving the CG back by only 3/4 inch, the model turned into a delightful floater with great flight characteristics. I think of the Duck as a large equilateral delta which includes both wings. The stall is really not well defined but with nose high, it turns into a mush with added lift from turbulence for smooth landings. At present, I am toying with the thought of making a twin motor taildragger with swept back in-line wings similar to the Georgia Goose with a prominent rudder and no horizontal tail. What do you all think it should look like?
Charles
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