RE: Is a Heat Gun really needed ?
Bob,
In the long run, as others mentioned above, a heat gun is a great tool to have in the shop. I've used mine for all sorts of things.
Personally, I prefer not to use one for covering. I especially wouldn't use one on the wings of the model you have pictured in your original post.
To help prevent warps of an open frame structure, I attach/iron the edges of the covering down as per standard covering practices. Then I gradually tighten the covering with the iron. I set the iron's temperature so that is will slightly shrink the covering, then alternate between the top and the bottom of the wing to tighten both sides evenly. Then I bump the temperature up a bit (~20 degrees) and go back over the wing again. I repeat this several times until I'm happy with the finish.
All said, you could certainly do the same as I do with a heat gun, and many modelers do so very sucessfully. I still like using the iron, though, because it gives me exact control over the shrinking AND I can guarantee that the covering is properly adhered to each rib and stringer.
Good luck, Gary
PS. I have family in Cullowhee - do you know any retired professors from WCU? Perhaps you're one too?