I bought a Super Chipmunk from a friend and I can not find what company it is made by... I was wondering if anyone had any suggestions to maybe find out. Also, its a .40 size I know and the one thing I need to get it flying is the COG. I don't have any source to find out the COG and I don't want to put it in the air without balancing it. Thanks

a good starting point for CG would be at 1/3 measured from the leading edge pf the wing...be sure to balance upside down as the Chipmunk is a low wing

If it's a built up wing and you can tell where the spar is, you can balance it on the middle of the spar and be right 99% of the time. Also anywhere from 25% to 33% of the MAC (mean aerodynamic cord) would be right. I'd start at the 25% point and fly it there. Then if you want you can move the battery around and progress back, in small amounts (1/8" or so) till it flys like what you want.

It has a tapered leading edge. Would this 1/3 be measured at the root or the tip? There is a considerable difference depending where it is measured.

E S

Carl Goldberg, 1/4 front of main spar to 1/4 rear of main spar. I fly mine in the center of main spar.

As far as the tapered leading edge goes, you need to compute the MAC. (That's stands for Mean Aerodynamic Cord) this is the average cord taking into account the length at the root, the length at the tip and the sweep. I don't have the formula at hand but you can go to http://www.geistware.com/rcmodeling/cg_calc.htm#cg
and fill in the info and it will do it for you. When it wants what percentage of MAC, you want to start with 25%. OR if it were me I'd just balance it on the wing spar!