# M.A.C. for Elliptical Wings

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#### gerome

##### Member
Just quick question. I'm having trouble integrating the formula for the MAC of an elliptical wing. The book gives the formula
MAC = 1/S integral of c squared dy upper limit of b/2 and lower limit of -b/2.

#### wsimpso1

##### Super Moderator
Staff member
Log Member
An ellipse is described by the locus of points with this function: 1 = x^2/a^2 + y^2/b^2. If y is the spanwise direction, b is the semi-span, a is the root chord of the wing, y is the chordwise position, and x is the chord at the chosen y. Have fun with the calculus.
Billski

#### gerome

##### Member
Have fun with the calculus.
Billski[/QUOTE]

Thanks for the reply Wsimp and Marc. I tried another approach. Since the shape of my wing is ellipse i used the formula for finding the centroid of half ellipse. I projected it vertically and that is the MAC i used. But i think I will also try that equation you gave me to check if my approach is legit. THanks.