Trailing edge question....
 

Hi,

I've made a 4-star 120 wing and fully sheeted it.

The trailing edge is now 15mm thick. The (kit) aileron is 9mm thick.

I'm considering making up my own ailerons, but before I do, I just want to get some impressions about another option: Sanding the TE (top and bottom) at a taper to bring it down to a 9 mm thickness.

If I did this, will there be any negative effects? Flutter? Reduced stall speed?

Thanks,

BK

RE: Trailing edge question....
 

What you propose should be fine. Most model airplane airfoils are straight from the designer's imagination. "Real" airfoils don't behave the same in small scale as they did when being tested in a wind tunnel. Almost any shape that looks like an airfoil ends up working fine.

I normally build up ailerons using 1/32" or 1/16" contest balsa sheet and a whole lot of ribs spaced about 1" apart. It's lighter than aileron stock and much less likely to warp.

RE: Trailing edge question....
 

Your new trailing edge should work just fine, since, in my opinion, the stock trailing edge on the Four-Star is a bit flimsy, which probably contributes to this airplane's propensity for wing flutter. To take full advantage of the thicker trailing edge, I would make up new, thicker ailerons from very soft balsa to match the thickness of the wing's trailing edge. Alternatively, you could build up new ailerons from 1/16" medium density sheet and ribs, to save weight. It is important to keep ailerons as light as possible to reduce the flutter tendency.