Fabulous models - I like the cool dark tones of the Snipe pic; but the rigging etc. on the SE is superlative.
I agree with Petrov, IMHO you'd help yourself a lot using a light grey or blue or even brown background, especially with dark subjects like these.
Another point is that you don't necessarily need more lights - I use three at most, usually two - but do make copious use of reflective surfaces eg. large white card, maybe a sheet or simply a nearby wall.
Brilliant!
Mark