Aspect ratio (aerodynamics)

In aeronautics, the aspect ratio of a wing is the ratio of its span to its mean chord. It is equal to the square of the wingspan divided by the wing area. Thus, a long, narrow wing has a high aspect ratio, whereas a short, wide wing has a low aspect ratio.

Aspect ratio and other features of the planform are often used to predict the aerodynamic efficiency of a wing because the lift-to-drag ratio increases with aspect ratio, improving fuel economy in aircraft.

The aspect ratio ${\displaystyle {\text{AR}}}$ is ratio of the square of the wingspan ${\displaystyle b}$ to the projected wing area ${\displaystyle S}$, which is equal to the ratio of the wingspan ${\displaystyle b}$ to the mean aerodynamic chord ${\displaystyle {\text{MAC}}}$:

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