Need help,my Tuff Flight Predator needed a full stick of lead to balance it and i was wondering what i did wrong.Had to put the lead on the engine mount half a stick on either side and and this is making it a little squirrelly when it loops.Engine is a Norvel.25 and battery is on leading edge of wing.Servos are mounted in front of the main spar and centered on the wing.Any help would be greatly appreciated and thanks in advance.