Hello all, I'm in the process of building an ultralight glider. (to be piloted by me) As part of the construction process, I need to bend some aluminum tubing into an airfoil shape. This tubing will form the top of the wing. The bottom of the wing is flat. The shape of this particular airfoil is such that the forward section is a 1/4 ellipse, and the rear section is a large-radius circular section. When bending aluminum, the material exhibits a property called bounce-back. If you bend it around a circular wooden form, it will bounce back to a larger diameter circular shape. I'd like to focus on the ellipse portion of the airfoil. I wish to cut a wooden form such that I can bend my aluminum tubing around the form and it will bounce back to the elliptical shape I desire. The shape I create will need to have the same length as the final ellipse section. It will also need greater curvature at every point so that my tubing will bounce back to the shape I desire. In bending an aluminum bar, (at a single point) I found that the bounce-back was about 5 degrees. I see no reason not to use that as a starting point. How is curvature defined for an object like an ellipse? I need to know the curvature at each point so that I can increase it by 5 degrees at each point. Can anyone suggest how I might go about creating the shape of the wooden form I need? Thanks!