not only does these things work on the rudder. they will work on the ailerons. come on, admit it. you have a slight heavy wing. I do. I figure it's the force of the motor cus it is to the left. I'm going to take a small piece of balsa that I have, wedge, and put it under the right aileron. I put one on my rv. I really don't need it, but my trim I do have works dead center if I have it. it's really to offset for the wife not being in the plane. I take it off when she is with me. yes I have it taped on under the right side. easily taken off when she goes with me. so I'm going to take my extra piece and put it on the kitfox.