What is defined as the acute angle between the chord line of the airfoil and the relative wind?

What is defined as the acute angle between the chord line of the airfoil and the relative wind?

• A. Pitch angle
• B. Bank angle
• C. Sideslip angle
• D. Angle of attack

Answer: (D)

Angle of attack is the acute angle between the airfoil's chord line and the relative wind. This shows how the wing is tilted to the oncoming air, which directly sets the lift generated. A small angle keeps the flow attached and produces lift smoothly; as the angle increases, lift rises until the flow can no longer stay attached and stall occurs at a critical angle. The other terms describe aircraft attitude or wind direction relative to the fuselage but do not define how the wing is oriented to the oncoming airflow, so they aren’t the angle of attack.

Angle of attack is the acute angle between the airfoil's chord line and the relative wind. This shows how the wing is tilted to the oncoming air, which directly sets the lift generated. A small angle keeps the flow attached and produces lift smoothly; as the angle increases, lift rises until the flow can no longer stay attached and stall occurs at a critical angle. The other terms describe aircraft attitude or wind direction relative to the fuselage but do not define how the wing is oriented to the oncoming airflow, so they aren’t the angle of attack.