Hi all,

I just tried to reply and screwed it up so you may find two replies. This one should be complete.

Ok here is an easy and nearly exact way to find the CG of most any wing.

Measure the root in this case 10.5 inches. Measure the last tip rib and here it is 7.5.

Add the root and tip measurements together and devide by 2. So we are looking for the rib that measures 9 inches (the MAC).

Find the 9 inch rib and measure from the liading edge back 25 percent (2.25 inches minimum CG). Then measure 30 percent (2.7 inches maximum CG).

Remember these measurements are on the 9 in rib. You can draw a straight line from 2.25 etc. to the fuse if you like and mark the CG there.

This works for me and is a safe starting CG. I start there and sometimes make small adjustments after the maiden flight.

I Hope this is helpful. There is actually a longer formula for finding the CG but the above puts you nearly as accurate.

Arno