Which drag type is primarily associated with rotor-tip vortices?

Which drag type is primarily associated with rotor-tip vortices?

• A. Induced
• B. Profile
• C. Parasite
• D. Form

Answer: (A)

Induced drag is the drag that comes from the production of lift. In a rotor with finite span, each blade tip sheds a vortex and the rotor creates a downward flow through the disk. That swirling motion and downwash take energy from the rotor system, which shows up as an extra drag component—induced drag. The rotor-tip vortices are the main source of this energy loss, especially in hover when induced velocities are largest. Profile drag and parasite/form drag come from the blade’s shape and nonlifting surfaces, not from the lift-induced swirling at the tips.

Induced drag is the drag that comes from the production of lift. In a rotor with finite span, each blade tip sheds a vortex and the rotor creates a downward flow through the disk. That swirling motion and downwash take energy from the rotor system, which shows up as an extra drag component—induced drag. The rotor-tip vortices are the main source of this energy loss, especially in hover when induced velocities are largest. Profile drag and parasite/form drag come from the blade’s shape and nonlifting surfaces, not from the lift-induced swirling at the tips.