Quiz on Aerodynamics and Angle of Attack

What is the angle of attack?

• The angle between the wing and the ground

• The angle between the aircraft and the horizon

• The angle between the chord line of an aerofoil and the undisturbed, relative airflow

• The angle between the wing and the tail of the aircraft

Answer explanation

The angle of attack is defined as the angle between the chord line of an aerofoil and the undisturbed, relative airflow. This is crucial for understanding lift generation in aerodynamics.

What happens when the angle of attack exceeds the critical angle?

• The aircraft gains more lift

• The wing stalls

• The drag force is eliminated

• The aircraft speeds up

Answer explanation

When the angle of attack exceeds the critical angle, the airflow over the wing becomes turbulent, causing a loss of lift and resulting in a stall. Therefore, the correct answer is that the wing stalls.

What is the effect of lowering the flaps on a wing?

• It decreases the drag force

• It increases the lift coefficient

• It reduces the surface area of the wing

• It decreases the camber of the wing

Answer explanation

Lowering the flaps increases the lift coefficient by enhancing the wing's camber and increasing the effective surface area, allowing the wing to generate more lift at lower speeds.

What is the primary cause of lift on a wing?

• The wing's weight is reduced

• The wing's speed is increased

• The static pressure above the wing is greater than below

• The static pressure below the wing is greater than above

Answer explanation

Lift is primarily generated because the static pressure below the wing is greater than above. This pressure difference creates an upward force, allowing the wing to rise.

What is the center of pressure (CP)?

• The point where the maximum lift is generated

• The point where the drag force is minimized

• The point where the total aerodynamic reaction force acts

• The point where the total weight of the aircraft acts

Answer explanation

The center of pressure (CP) is the point where the total aerodynamic reaction force acts on an aircraft. This point is crucial for stability and control, as it influences how the aircraft responds to aerodynamic forces.

What is the effect of increasing the angle of attack on lift?

• Lift remains constant

• Lift decreases

• Lift increases

• Lift becomes zero

Answer explanation

Increasing the angle of attack enhances the airflow over the wings, leading to greater lift until a critical angle is reached. Therefore, the correct answer is that lift increases.

What is the role of camber in a wing?

• It decreases the lift coefficient

• It reduces the wing's surface area

• It increases the drag force

• It increases the lift coefficient

Answer explanation

Camber is the curvature of a wing, which helps to increase the lift coefficient by altering the airflow over the wing. This enhanced lift is crucial for better performance during flight.

What is the relationship between lift and drag?

• Lift is parallel to the relative airflow, and drag is perpendicular

• Both lift and drag are perpendicular to the relative airflow

• Lift is perpendicular to the relative airflow, and drag is parallel

• Both lift and drag are parallel to the relative airflow

Answer explanation

Lift acts perpendicular to the relative airflow, allowing an object to rise, while drag acts parallel to the airflow, opposing the object's motion. Thus, the correct relationship is that lift is perpendicular and drag is parallel.

What happens to the airflow when the angle of attack is too steep?

• The airflow becomes more streamlined

• The airflow becomes more turbulent

• The airflow becomes laminar

• The airflow remains unchanged

Answer explanation

When the angle of attack is too steep, airflow can no longer follow the contour of the wing, leading to increased turbulence. This turbulence can result in a loss of lift and potential stall, making 'the airflow becomes more turbulent' the correct choice.

What is the effect of streamlining on an object moving through a fluid?

• It has no effect on drag

• It increases turbulence

• It reduces turbulence

• It increases drag

Answer explanation

Streamlining an object reduces turbulence by allowing the fluid to flow more smoothly around it. This decrease in turbulence leads to lower drag forces acting on the object, making it more efficient in fluid movement.