Which term describes resistance to motion through air, as used in the rotor aerodynamic model?

• A. Drag
• B. Lift
• C. Thrust
• D. TAF

Answer: (A)

Drag is the resistance an object experiences as it moves through air. In rotor aerodynamics, each blade slice through the air and the air pushes back, opposite the blade’s motion. This opposing force comes from skin friction and pressure differences around the blade, and it shows up as part of the power required to keep the rotor turning. Lift is the force that acts upward to support weight, and thrust is the reaction force along the rotor axis that produces forward or upward motion. TAF isn’t the term used to describe this resistive effect. Drag, therefore, is the correct concept describing resistance to motion through air in the rotor aerodynamic model.