I've come up with (a long time ago...) a method of making a set of ribs for a tapered wing that produces ribs that are not only accurate in planform (side view), but also have the correct thickness taper (front view), and leading edge taper (top view). This method of rib making is part of a total wing building system that I call the Lost-Foam process. In actuality, no foam is "lost." I just use the foam parts for templating and fixturing. I'll not go into a full explanation of the Lost-Foam process (which, by the way, I wish now that I'd named "Foam Form" building...), but I will post a few photos that show just a part of the sequence. In this case the photos depict the steps required to make as perfect-fitting ribs as I know how to produce. This will require that I post the photos in several responses...
If, after perusing the photos, you'd like a booklet that explains the entire Lost-Foam process, please drop me an email and I'll send you my Lost-Foam Instruction manual in PDF form at no charge.
Later - Bob Hunt