What happens when 2 combat models occupy the same space

I've had a few midair collisions over the years. Usually the engine survives...but not always if it takes a direct hit from the other guy's crankshaft.

CL Combat

These are models in the 4' wingspan range with motors .35 cubic inch that can generate in the range of 1hp when run on fuel that's maybe 40% nitromethane 40% methanol and 20% oil (I prefer pure Castor oil , others use synthetics or a blend)