I'm pretty sure it's Jim Gager's He 100, although Gager's design called for a constant-chord midsection from the root to about where the wheels are. But the builder may have sanded a straight taper into it, or perhaps used cores from a Jim Gager P-39/P-63. The airfoil would've been close enough to work.

As QM15 airplanes go, this was definitely one of the better ones. The upright engine is a no-hassle setup, and the wide-stance, wing-mounted landing gear made for great ground handling. You should clean it up and fly it for sport!

Cheers,
Duane