This is EASY if you can't find pre-shaped ailerons at the local hobby shop.

Figure out how wide you want them. Thats the cord. distance from the leading edge too the trailing edge.

Now cut some 1/16" balsa sheets to length and cut them about 1/2" short of the cord you want.

Now you need to know how thick they are at the leading edge where the hinges are. Let's say they are 1/2" thick. You already have 2 pieces of 1/16" balsa--so thats 1/8" already. You need 3/8" to make them 1/2" thick when they are done.

All you do is cut some triangle pieces of balsa. Make them 3/8" tall on the fat side and taper them down to nothing on the skinny side. If your aileron cord is going to be 2"--then you cut yuour triangles about 1 7/8" long and 3/8" high. Now you got RIBS.

Lay a sheet of 1/16" balsa down flat on the board. Glue a rib on each end. Now glue 4 or 5 ribs in the middle spaces. Add a hard point made from hard ply or basswood for your control horn. Glue it in between a couple ribs.

Now go in between all the ribs and fill in with a piece of balsa. This is for your hinges to bite into.

Now put the top sheeting on. Your almost done.

Now get a piece of 1/2" triangle stock and glue it to the leading edge. Sand the point down a tiny bit to soften it up.

Sand. Cover. Hinge.[sm=thumbup.gif]

First pic is a side view.

Second pic is a top view looking down on the aileron before you put the top skin on.

Triangle ribs are purple
Balsa skins are blue
Control horn hard point is green
Balsa filler and triangle stock is brown