The drag polar is a graphical representation in aerodynamics that illustrates the relationship between an aircraft’s lift coefficient () and its drag coefficient (). It provides valuable insights into the aircraft’s aerodynamic performance by displaying how drag varies with changes in lift coefficient. However, the relationship between lift coefficient and drag coefficient can be described by the following equation, which represents the drag polar:
Where:
- is the total drag coefficient,
- is the zero-lift drag coefficient (parasite drag coefficient),
- is the lift coefficient,
- is the aspect ratio of the wing,
- is the Oswald efficiency factor, representing the efficiency of the wing in generating lift. It typically ranges from 0.7 to 0.9 for subsonic aircraft.