eglinflyers

FOUND THIS:
How to figure CG

Pick a point of reference; say the tip of the spinner. If using the spinner, use a square or other straight edge to locate tip of spinner straight down to the workbench.
Put a string across the main wheels, over the axles, and measure that distance from the spinner.
The middle of that line will be your axle reference point (for both wheels).
1. Measure the (d)istance from the spinner to the centerline of the wheels.
2. Measure the (d)istance from the spinner to the tail (or nose wheel axle, whichever applies)
3. With the plane in the flying attitude (tail up and wing attached in place) (w)eigh each wheel and the tail (for tail dragger). If it is a tricycle gear, then (w)eigh nose wheel, not the tail.
Then each wheel's weight is multiplied by that distance (spinner to axle point) which gives you inch pounds.
Add the 3 of them for total inch pounds and divide the total inch pounds by the total weight (sum of wheel/tail weights) and you get the distance from the reference point to the CG in inches.

(d1 x w1) + (d2 x w2) + (d3 x w3) ÷ total weight = distance from reference point to CG

(distance to wheel 1 x weight of wheel 1) plus
(distance to wheel 2 x weight of wheel 2) plus
(distance to wheel 3 or tail x weight of wheel 3 or tail)
Divided by total weight = distance from reference point to CG in inches Ed Francis