Half a sheet of Correx... cut the hard way.

It cuts very easily with a sharp knife, too, and less fumes than a hot-wire!
I've got some I was going to use as wing-sheeting, but never got a round tuit. The stuff I've got doesn't take adhesives, very well, though, because it is so flexible - has to be one of the contact type (which eats polystyrene!)
The stuff I have is skinned both sides, and has square 'holes' which are great for shoving 2mm stiffeners down!
For sharp radii, all you need to do is run the BACK of a knife down the skin between the 'holes' to crease the plastic, obviously on the inside of the curve, and it then rolls round a small diameter rod, so you can use a 1cm dowel as a leading edge.
Comes in all colours too, especially glossy black! Once done, it is waterproof. Don't use glow fuel so I cannot comment on that, and I suspect that petrol will 'eat' it.