The 10 Lb weight is final flying weight that's including engine and radio: I weigh the assembled plane 5 lbs then I weigh my engine with muffler engine mount and vibration isolators 2lbs 2 oz, my radio system weighs 1.0 lb so thats 8lbs 2 oz, unless my weighing scale is off then!!!!. Definitely the 45 Homy is to big of an engine, the most that I would go with it would be a Ryobi 31CC or similar displacement and that's putting a lot of an engine, this plane is similar in size to the Carl Goldberg ultimate