The Mean aerodynamic wing depth (MAC = Mean Aerodynamic Chord) is a mathematically determined, representative wing depth (airfoil depth) that replaces a real wing in terms of its aerodynamic properties. It represents the imaginary rectangular wing depth at which the Total force (buoyancy) and the Pitching moment of the actual wing would be identical.
What is a "chord"/wing depth?
- A chord, from the English Mean Aerodynamic Chordis the straight-line distance from the leading edge to the trailing edge of a sash at any point.
- Aircraft wings vary in shape (tapered, swept, etc.), so the MAC provides a single average chord that accurately represents the aerodynamic behavior of the wing.
- For complex wings (e.g. multi-part), the MAC is determined from aerodynamic integration or CAD models.
Key terms
- LEMAC (Leading Edge of MAC): Where the MAC begins, normally measured from a defined line.
- %MAC: The position of the center of gravity in percent along the MAC (e.g. 25 % MAC means that the center of gravity is one quarter along the chord).
In short
The MAC is the mean airfoil depth of a wing in which the aerodynamic effects of the entire wing - in particular lift and moment - are realistically simplified.
It is mainly used to
- the Center of gravity (CG) in relation to the wing depth,
- the aerodynamic stability to assess,
- design and approval criteria (e.g. according to EASA or FAA).
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