> This >photo of Richard Shirley's trailing edge shows a blunt profile. >http://www.bouyea.net/gathering2004/P1002293.jpg >The Cirrus people told me this is done to improve the feel at higher rates >of speed. (Interestingly, both Cirrus and Richard have aluminum ailerons.) >Most of the KRs I have seen have very thin (i.e. sharp) trailing edge >sections. >John Bouyea ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
I read years ago why designers went to a blunt trail edge but don't recall the exact reasons. I seem to recall something about keeping the boundary layer attached better or something. Many of the newer design aerobatic aircraft have blunt trailing edges. Check out the "One Design" series. Most all of the jets I refuel , Citations, etc., all seem to have blunt trail edges on the wing and aileron of at least 1/4 to 3/8 inch. All my trail edges on wings, ailerons, rudder, and elevator, all have 1/8 inch rounded trail edges of flox and resin sanded to shape. They perform well and so far little if any damage from handling. I'd stay away from too thin trail edges for damage control and ease of building with the thicker ones if nothing else. To build a straight trail edge, glass one side of the wing. Sand the trail edge straight with a long sanding board then rotate and glass the other side leaving the trail edge the thickness you want in the sanding of the foam. Sand the second side glass to match the first. Using a small Dremel tool wire brush or equivalent, hog out the foam approx 3/8 of an inch. Fill the void left with resin rich flox, let cure and sand to the shape you want. Larry Flesner
