RE: Need Help!!! Great Planes Cap 21 Giant Scale (88" wingspan)
the imac 10% rule has always been meaningless, since i am not aware of any event that had the resources or the need for it to be properly enforced. but assuming that it is a valid consideration, your next problem is finding the full scale documentation on a cap 21. but perhaps the best idea is to convert into something else - like a 231/EX...take a wing planform from an Extra 300S and design it for the Cap. It will fly much better and no one will know the difference.
Bob Mellen is a local, and a very good guy.
P