Bob,

Define "straight and square". Most wings have leading edges that are swept back and/or trailing edges that are swept forward. In fact, unless it's a constant chord wing (a la the old HP-10), the leading and trailing edges aren't parallel. And neither one may be perpendicular to axis of the fuselage (i.e., direction of flight). So how to align the foam core board on which you trace the airfoil?

I guess if all you're doing is creating templates to use during refinishing, it doesn't matter how you align it so long as you can duplicate the same alignment after the old gel coat is stripped off and new gel coat is applied. In that case, aligning the "chord" perpendicular to the leading edge probably works fine. But is that true if you're really trying to pull coordinates?

Chip Bearden