What does 'mean chord' refer to in aerodynamics?

The term 'mean chord' is used in aerodynamics to refer to the average distance measured from the leading edge to the trailing edge of an airfoil or wing. This measurement is essential as it helps to calculate various aerodynamic properties, including the aspect ratio of the wing, which can influence its lift characteristics and overall performance.

Mean chord is particularly important because, unlike a simple average or a linear dimension, it considers the varying shape of the wing along its span. For a tapered wing, for instance, the mean chord can be calculated by taking the total area of the wing and dividing it by its wingspan, which gives a more accurate representation of the aerodynamic characteristics than simply measuring the width at one point.

In contrast to this, the average width of an aircraft's wing and the total length of the wing structure do not account for the aerodynamic properties that mean chord captures. The thickness of the wing, while significant in terms of structural integrity and drag, is a different measurement that does not correlate with the mean chord specifically. Thus, the correct understanding of mean chord is critical not just for design purposes, but also for calculations involving lift and drag forces acting on the wing.