The drag curve or drag polar is the relationship between the drag on an aircraft and other variables, such as lift, the coefficient of lift, angle-of-attack or speed. It may be described by an equation or displayed as a graph (sometimes called a "polar plot").[1] Drag may be expressed as actual drag or the coefficient of drag.
Drag curves are closely related to other curves which do not show drag, such as the power required/speed curve, or the sink rate/speed curve.