Pe, I see what you mean. I think perhaps the best use for it,is getting the batteries and radio gear, ect placed in the right places to work out a final balance. If you had the dimention for the CG from the leading edge, you could get evrything in place for a good balance job. Also if the CG was not know off your plans, you could find someone online that has the same airplane and get the CG point from him. Thanks for the reply, and have a nice day. Capt,n John