JayParke

I am building a built up wing using foam as a center section and also using four 1/2" foam ribs per side. The wing itself is 48" span and 11" chord with 2.5" at the thickest point. I have spars in the thickest point of the wing top and bottom also 1" or so in front of that are some smaller spars top and bottom. Then I have a single spar in the LE. Also I have a spar top and bottom 2" behind the middle spar in the wing. And lastly there's one small spar at the TE.

Now my problem is that my wing will twist if I grab it by the wingtips and twist it. It doesn't twist a lot or extremely easily. Just more than I would imagine should be allowed. Now I want to fix this but I don't know how to go about it. I don't want to sheet the wing at all. That defetes the whole purpose. I was thinking of taking some balsa and making " M " peices in at the TE of the wing to about midpoint. "I hope that makes sense?" But I don't know if that would get rid of the twist in the wing or not?

Are there any websites that give valuable pictures or ideas for building your own built up wings as light as possible but keeping it strong? Or any referance as how to go about building built up wings?

Thanks for any help,
Josh

DICKEYBIRD

You'll be amazed how much the torsional stiffness of your wing will increase when you cover it! MonoKote when applied drum tight will add a lot of stiffness.

HTH
Milton Dickey