That's a little less than 12 sq. feet of wing area; at ten pounds that comes out to less than 15 oz/sq. feet wing loading, Even if you stick enough stuff in it to get the weight to 12 or 13 pounds, the loading will still make this plane a floater. I'd say a .90 - 1.00 4-stroke would be a great engine. Turn a nice big prop with 5-6 pitch, it should fly like it was intended to. It still would be nice to know what it is.