the predator motor from HF is a big 4 cycle gas engine similar to an 8hp Briggs engine found on a lawnmower. it's meant to power go karts and lawn equipment, not airplanes. it would be way too heavy, bulky, slow and lacking in power, to be used in an airplane. my son and I used to race go-karts in the "predator class" , top rpms with those engines is about 4,000 rpm. on gas and/or alcohol.