RE: 40 size plane for combat?
I built a spad devistatator for the exact same purpose. Cheap, tuff easy to repair and can fly slow or fast. With the v tail it turns on a dime. used micro hs-81 servos except on the alerons. 48" span. I flew one of A's foamies last round and did well with it but i think i like the spad a little better.