<P> Parasitic drag is drag that results when an object is moved through a fluid medium . In the case of aerodynamic drag, the fluid medium is the atmosphere . Parasitic drag is a combination of form drag, skin friction drag and interference drag . The other components of total drag, induced drag, wave drag, and ram drag, are separate types of drag, and are not components of parasitic drag . Parasitic drag does not result from the induction of lift on the body, hence it is considered parasitic . </P> <P> In flight, induced drag results from the lift force that must be produced so that the craft can maintain level flight . Induced drag is greater at lower speeds where a high angle of attack is required . As speed increases, the induced drag decreases, but parasitic drag increases because the fluid is striking the object with greater force, and is moving across the object's surfaces at higher speed . As speed continues to increase into the transonic and supersonic regimes, wave drag grows in importance . Each of these drag components changes in proportion to the others based on speed . The combined overall drag curve therefore shows a minimum at some airspeed; an aircraft flying at this speed will be close to its optimal efficiency . Pilots will use this speed to maximize the gliding range in case of an engine failure . However, to maximize the gliding endurance, the aircraft's speed would have to be at the point of minimum power, which occurs at lower speeds than minimum drag . </P> <P> At the point of minimum drag, C (drag coefficient of the aircraft when lift equals zero) is equal to C (induced drag coefficient, or coefficient of drag created by lift). At the point of minimum power, C is equal to one third times C . This can be proven by deriving the following equations: </P> <Dl> <Dd> F d r a g = q A s C D (\ displaystyle F_ (drag) = qA_ (s) C_ (D)) </Dd> </Dl>

Total drag on a body is the sum of