On a wing, lift and drag act in which directions relative to the flight path?

On a wing, lift and drag act in which directions relative to the flight path?

• A. Lift perpendicular to the flight path; Drag parallel to the flight path
• B. Lift parallel to the flight path; Drag perpendicular
• C. Both perpendicular
• D. Both parallel

Answer: (B)

Lift acts perpendicular to the relative wind (the airflow seen by the wing), which is opposite the aircraft’s flight path. Because the flow comes from ahead and toward the tail, this lift force ends up perpendicular to the flight path. Drag, on the other hand, acts along the direction of the relative wind, i.e., parallel to the flight path, opposing the aircraft’s forward motion. So the correct description is that lift is perpendicular to the flight path, and drag is parallel to it.

Lift acts perpendicular to the relative wind (the airflow seen by the wing), which is opposite the aircraft’s flight path. Because the flow comes from ahead and toward the tail, this lift force ends up perpendicular to the flight path. Drag, on the other hand, acts along the direction of the relative wind, i.e., parallel to the flight path, opposing the aircraft’s forward motion. So the correct description is that lift is perpendicular to the flight path, and drag is parallel to it.