Private Pilot Private Exam

Angle of attack is defined as the chord line of an airfoil and the...

1. Direction of takeoff.

2. Direction of the relative wind.

3. Angle of descent.

4. Flight path of the aircraft.

The correct answer is: Direction of the relative wind.

Angle of attack is a critical concept in aerodynamics that is defined as the angle between the chord line of an airfoil and the direction of the relative wind. The chord line is an imaginary straight line that runs from the leading edge to the trailing edge of an airfoil. The relative wind is the flow of air that is felt by the airfoil and it is essentially the airflow direction relative to the wing as the aircraft moves through the air. Understanding this relationship is essential because the angle of attack significantly influences the lift generated by the airfoil. As the angle of attack increases, lift increases up to a certain point known as the critical angle of attack, beyond which lift drastically decreases and may lead to a stall. The other options do not accurately define angle of attack. The direction of takeoff relates to the orientation of the aircraft relative to the runway, the angle of descent pertains to the descent path of the aircraft rather than the airflow interaction, and the flight path refers to the trajectory of the aircraft itself. These terms are important in aviation but do not define the angle of attack, which is fundamentally linked to the relationship between the airfoil and the relative wind.