What is the mean aerodynamic chord?

The mean aerodynamic chord (MAC) is a measure of the average chord length of an aircraft wing. It is a reference dimension used to determine various aerodynamic and structural properties of an aircraft.

The MAC is calculated by dividing the wing area by the wing span. It represents the average chord length from the wing root to the wing tip and is usually measured at the wing root.

Several important parameters of an aircraft are based on the MAC. These include the calculation of the aerodynamic center, which is the point along the MAC where the lift force is considered to act. The location of the aerodynamic center is crucial for stability and control analysis, as well as for determining the aircraft's center of gravity.

The MAC is also used to calculate aerodynamic coefficients such as lift coefficient and moment coefficient. These coefficients are essential for analyzing the aircraft's performance, stability, and control characteristics.

Additionally, the MAC is used in structural analysis to determine the wing bending moment distribution and to evaluate the wing's structural integrity.

The MAC is often used as a reference dimension alongside other aircraft parameters such as the reference airspeed and reference area when conducting wind tunnel testing, flight testing, and aircraft design. It provides a standardized measure of the wing's characteristics and allows for meaningful comparisons between different aircraft designs.

Overall, the mean aerodynamic chord is an important parameter in aircraft design and analysis, serving as a fundamental reference dimension for multiple aerodynamic and structural calculations.