ORIGINAL: Villa
Hi Phoenixangel
In many of the early instructions you were directed to crease the Coroplast top side of the wing at the point it made contact with the yardstick spar. That is what I did with my first Coroplast wing. I do not put in that crease anymore and the wing is much smoother. As the saying goes, try it, you will like it.
Villa has it right! It's harder to get the coro wing together if you don't crease it above the spar, but it's worth it.
Jack