The form shown below will calculate the position of the Center of Gravity (CG) of a model airplane wing as measured from the leading edge of the Root Chord. If you would like to know the percentage of the Mean Aerodynamic Chord (MAC) for a given position of the CG you should use the form on The Mean Aerodynamic Chord Page.

 

Enter Root Chord (A):
Enter Tip Chord (B):
Enter Sweep Distance (S):
Enter Half Span (Y):
Enter %MAC Balance Point:
Sweep Distance @ MAC (C) =
Mean Aerodynamic Chord (MAC) =
MAC Distance from Root (d) =
Balance Point @ Root Chord (CG) =

A good starting point for the %MAC  is about 25-35 percent.