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Old Jan 14, 2013, 08:10 AM
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Dr John
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Lake Placid, Florida
Joined Dec 2001
2,712 Posts
I have had good luck on my last few builds by sanding an airfoil into a wing cut from 6mm Depron. First I embed a carbon fiber spar into the bottom of the wing and then start the sanding. I start with 80 grit paper on a half sheet sanding block as used on drywall seams. Round the leading edge about 25% of the cord back on the top and taper the rear 60% to a thin trailing edge. Cover the bottom with 3/4 oz fiberglass cloth wrapping about 13mm around the leading edge onto the top surface. I use water based polyurathane rather than epoxy to save weight and work. After the bottom is dry feather out the edge of the glass on the top surface and cover the top wrapping around the leading edge about 13mm onto the bottom. This gives a double layer on the leading edge for a bit more ding resistance. This has worked well on small wings up to about 22-24 inches. The actual airfoil is not all that critical at these sizes but try to keep the left and right panels symetrical.

Dr John
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