Oh what are us engineers to do?????

I'm one aeronautical structures engineer that usually stays way clear of these debates!

Funny, I'm doing a structural analysis of a full scale aluminum, general aviation wing spar right now. By and large, I'd say that this analysis is probably simpler than that of our models!

Vertical or horizontal you ask? Well, I can't say, and won't say, because every model and situation is different. I happen to believe that one rule doesn't fit all. Honestly, and this is a big point, the shear stresses in most of our models is very low. With plenty of ribs and the usual sized spar caps, we could probably do without shear webs for the outer 3/4 wing span of a sport model. To really help your wing: spend plenty of time getting that center wing joint right. Oh, don't let the kids or dog step on the wing - that's what really brings those spar caps together.

Gary