Contrary to Rays helpful suggestion of rolled acetate for the exhaust duct, I have used very thin card/thick paper, painted with PVA and then swooshed over with silver spray paint (to replace the rolled up acetate!!)
It is nice and stiff, and easy to do. It locates on the fan cowl at the front , and in the `ole at the stern with a blob of PVA stopping it shifting too much.
All I need is a pair of helmeted heads to adorn the cockpit transparency and the white roundels, and its finished.
(and an opportunity to test it)
Ashley