Yup, the scale depends on the airplane being modeled.

And you'd best simply work it out from the airplane you're interested in "piloting". The Ultimate just mentioned sounds like a 1/4 or 1/5 scale pilot would suit and it's a .40 size. I've got a couple of Corsair models. The Corsair had a 40foot 11inch wing. My 50size Corsair model has a 58" wingspan and that works out to 8.5:1 scale. It's a larger engined model than the Ultimate gboulton mentions yet would take almost half the size pilot. Even Hangar9's Corsair with it's 65" wingspan is a 1/7.5 scale and it's a 60-90 size model.