http://www.rccad.com/

There used to be software called ModelCAD, which was produced by a company called something like American Small Buisness, it has since turned into DesignCAD - there are various versions of it, I suggest getting the highest level you can afford. I also recommend Compufoil Windows - it is very good for laying out wings. Takes a bit of practice, and his code for airfoil ordinates is a bit different, but a little persistance pays off!

Jeff