I have this same yak and its very very tail heavy, I had to add 13oz of lead and bat, and ignition and its still tail heavy... I'm selling mine now... I had an spe 26cc engine on it and it flew like a warbird! It could do simple aerobatics but nothing I was into... I thought I was getting a deal on this combo but the weight I had to add just screwed it all up! this plane needs a Heavy 40cc to 45cc to make it perform the way its supposed to...