Hi Joe / Jim,
I prefer to calculate CG just as a % of Wing MAC.
That tool is considering tail area and efficiency !??? - really an assumption.
Normally when people refer to say 25% or 30% etc , they are referring to a straight % calculation of wing MAC.
Try;
http://www.palosrc.com/index.php?opt...1:ic&Itemid=50
http://www.palosrc.com/index.php?opt...1:ic&Itemid=50
Brian