Find this point for the main wing and stabilizers before continuing. This point is the Aerodynamic Center of the wing panel. Write this length down as it is important! With the GMC found, take 25% (1/4) of that distance from the leading edge and trace over to the root of the wing panel. Now measure the distance of the GMC as seen in the picture below. Draw a diagonal line from each end of the newly created lines and find where the two intersect. Next add the Root Chord (A) in front of and behind the Tip Chord (C). Take the lengths you found before and add the tip chord measure (C) in front of and behind the Root Chord (A).
This method will work for most wings, tapered or not. Below is a graphical representation of how to find AC of a wing panel by using the Mean Aerodynamic Chord (MAC) or Geometric Mean Chord (GMC).
The AC is where all the aerodynamic forces act of the wing. With those dimensions and areas recorded we now move onto finding the Aerodynamic Center.
