Helicopter Aerodynamics Drag Drag is the force that opposes the motion of an aircraft through the air. Total drag produced by an aircraft is the sum of the profile drag, induced drag, and parasite drag. Total drag is primarily a function of airspeed. It does not change significantly with angle of attack of the airfoil section, but increases moderately as airspeed increases.
Induced drag is the drag incurred as a result of production of lift.
Higher angles of attack which produce more lift also produce increased induced drag. In rotary-wing aircraft, induced drag decreases with increased aircraft airspeed. The induced drag is the portion of the total aerodynamic force which is oriented in the direction opposing the movement of the airfoil. Think of it as lift which is in the wrong direction . Parasite drag is the drag incurred from the nonlifting portions of the aircraft.