Which drag relates to being parallel to and in the same direction as the resultant relative wind?

Which drag relates to being parallel to and in the same direction as the resultant relative wind?

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

Answer: (C)

Drag is the aerodynamic force that resists the motion through the air and lies along the line of the airflow. In rotorcraft terms, the resultant relative wind is the direction the air moves relative to the blade element. Drag acts parallel to that relative wind and in the same direction as the wind flow, not perpendicular to it. Lift, on the other hand, is perpendicular to the relative wind, which is why options that refer to a 90-degree offset don’t fit. An anti-parallel description would imply drag opposite the wind, which isn’t how this force is oriented. Understanding this helps explain why the drag component points along the same direction as the resultant relative wind.

Drag is the aerodynamic force that resists the motion through the air and lies along the line of the airflow. In rotorcraft terms, the resultant relative wind is the direction the air moves relative to the blade element. Drag acts parallel to that relative wind and in the same direction as the wind flow, not perpendicular to it. Lift, on the other hand, is perpendicular to the relative wind, which is why options that refer to a 90-degree offset don’t fit. An anti-parallel description would imply drag opposite the wind, which isn’t how this force is oriented. Understanding this helps explain why the drag component points along the same direction as the resultant relative wind.