Re: GU Canard No Generators


Larry Severson
 

At 10:29 PM 9/12/2009, you wrote:


Paul,

I've seen a claim by Nat Puffer that an accurate GU airfoil won't have this problem, which is why he kept it for the Cozy. Is there anyone flying a Quickie or Q2 without VGs and not having rain problems?

Rob
If you will go to http://worldofkraus/foils and compare the Dragonfly canard [the same as ours] with the GU25-5(11)8 [search the U for university area], you will find that what is on the Q2 is NOT a true GU airfoil. It has been modified with the max thickness moved forward and the leading edge sharpened from 4% radius to 1.5%. This causes the area of laminar flow to be reduced and the sharpness of down pitch in stall to be increased. In the 1970s, when the design was really created, a lot was still not known about airfoils by the general A/C designing group. It was assumed, wrongly, that the sharper nose would be faster.

P.S. I have a box with ALL of the foam segments for a GU canard plane beautifully cut. I would be happy to trade them, plus all of the hot wiring templates for an equal amount of uncut foam.


Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...

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