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. The airspeed that produces the lowest total drag normally determines the aircraft best-rate-of-climb speed, minimum rate-of-descent speed for autorotation, and maximum endurance speed.
Profile Drag is the drag incurred from frictional resistance of the blades passing through the air. It does not changesignificantly with angle of attack of the airfoil section, but increases moderately as airspeed increases.
Induced Drag is the drag incurredas a result of production of lift. Higher angles of attack which produce morelift also produce increased induced drag. In rotary-wing aircraft, induceddrag 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.
Parasite Drag is the drag incurred from the nonlifting portions of the aircraft. It includes the form drag and skin friction associated with the fuselage, cockpit, engine cowlings, rotor hub,landing gear, and tail boom to mention a few. Parasite drag increases with airspeed.
The graphic illustrates the different forms of drag versus airspeed:
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Page Last Updated on: Dec-25-2002