I quickly loaded the Whirlwind plan into Gmax and it displayed fine

It sounds like the plans may be slightly off. It happens quite often that the plan view does not match the side view for example.
I never make 2 wings. Why do things twice? Make one, get it right, then clone and add a mirror modifier. You can adjust the pivot point (anchor point) by selecting "affect pivot only" on the hierachy tab (I think)
You can use meshsmooth to smooth things out, but it adds an awful lot of polys.
The wing root is a pain to get right. I'm not sure what this part is like on the Whirlwind, but if it doesn't have a fillet, you can just model the wing straight through the fusalage.