Describe the relationship between drag and resultant relative wind.

Describe the relationship between drag and resultant relative wind.

• A. Perpendicular
• B. Anti-Parallel To Resultant Relative Wind
• C. Parallel To And In The Same Direction As Resultant Relative Wind
• D. At 90 Degrees To Lift

Answer: (C)

Drag is the aerodynamic force component that runs along the direction of the air flowing past the surface—the resultant relative wind. The resultant relative wind is the actual airflow direction seen by the blade, formed by the combination of the aircraft’s forward motion and the rotor-induced inflow. Since drag always resists the motion through the air, it points in the same direction as that airflow. In other words, drag is parallel to the resultant relative wind and acts in the same direction as the wind is moving past the surface. Lift, by comparison, would be perpendicular to this wind.

Drag is the aerodynamic force component that runs along the direction of the air flowing past the surface—the resultant relative wind. The resultant relative wind is the actual airflow direction seen by the blade, formed by the combination of the aircraft’s forward motion and the rotor-induced inflow. Since drag always resists the motion through the air, it points in the same direction as that airflow. In other words, drag is parallel to the resultant relative wind and acts in the same direction as the wind is moving past the surface. Lift, by comparison, would be perpendicular to this wind.