The zero-lift drag coefficient (CD,o) is a fundamental aerodynamic parameter that represents the drag coefficient of an aircraft when it is producing zero lift. In other words, it is the drag experienced by the aircraft when its lift coefficient (CL) is zero, which occurs when the aircraft is flying in straight and level flight without generating any lift.
- CD,o is the zero-lift drag coefficient
- CD is the overall drag coefficient of the aircraftÂ
- CL is the lift coefficient
- e is the Oswald efficiency factor
- AR is the aspect ratio of the wingÂ