Ernie Misner is Right! I had a Dazzler w/OS .40SF. Had to put 6 OZ of lead in tail. New plane on work bench is an Uproar. I'll be using an OS .32sx, nimh 720 pack, and Hitec HS 81 Servos. I may even make lightening holes in airframe. Light planes fly better and I figure that my uproar will be nearly one full pount lighter than my DAzzler was. Anyone can fly an engine, it takes a skilled pilot fo fly on the wing. Good luck and happy flying.