[NSRCA-discussion] CG

[Larry]

When you say moment arm = ac - ac I assume that "ac" = aerodynamic center?

How do you determine that "ac" point on a wing with a complex airfoil?

Larry
  ----- Original Message ----- 
  From: Nat Penton 
  To: NSRCA Mailing List 
  Sent: Monday, May 29, 2006 2:40 PM
  Subject: [NSRCA-discussion] CG


  The following formula was presented by noted British modeller Gordon Whitehead in How To Make Scale Models Fly ( 1980 ??). I have been using it over 20 years and find it  dead on for pattern:

         CG (from LE MAC) = MAC/6 + 0.25x As/Aw M
                      As -  area stab       Aw - area wing
                      M  -  moment arm,     ac to ac

  It is easy to use the graphic method to find the wing MAC. You can guess at the stab MAC and be close enough.

  The formula works on anything from a tailess to a Quickie.
                                               Nat Penton


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