As I mentioned just above, I have been flying a Delta Fighter 90(Vortex ARF from a few years ago) and it required 16 oz of lead in the tail. I decided to use some heavier materials and liberal epoxy aft of the CG. With the retract gear and all other equipment ready to fly less fuel, it weighs 9 1/2 lbs. It balanced perfectly at 21 1/2" forward of TE.