[NSRCA-discussion] MAC measurements

[Ronald Van Putte]

Good question.  There is no perfect answer.  The wing center section is not capable of producing the lift it would produce if the fuselage was not there, but lift is produced by the fuselage.  However, unless the wing has a lot of taper, the calculation of the location of the wing's aerodynamic center will be very close if you use the entire planform of the wing or just the part outside of the fuselage.  I use the entire wing planform because it's easier to measure.  Granted, the spanwise location of the calculated mean aerodynamic chord (MAC) for the entire planform of the wing is slightly further out the wing than the one calculated using just the part outside of the fuselage, but not worth worrying about, considering the other factors regarding three dimensional flow which we are ignoring in the calculation for the MAC.

Ron Van Putte

On Jun 9, 2013, at 8:50 AM, Stuart Chale wrote:

> When figuring the MAC of a wing do you continue the wing planform through to the center of the fuse and measure the wing root there or from the side of the fuse?  If so then along the fuse or parallel to the center line?
> Thanks,
> Stuart
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