My elevator blew off in knife edge.I have heard of this before but thought it was because of the builder cutting to deep when removing the covering on the tail.But minre broke outside the cut and the fiaring out by the first rib in the stab.But upon further insoection of mine it revealed that there was no spar or bracing in the H-stab just ribs and 1/16 inch sheeting.I would suggest fiberglass and/or flying wires.This airplane does some of the best lomcevaks i have seen. great knife edge too.Harrier has a lot wing rock but very contrlolable and you can mix it out.great plane while custamer support leaves something to be desired.