03 Aerofoils and Lift Drag

If the Angle of Attack and other factors remain constant, and the airspeed is doubled, lift will be:

• Doubled.

• One quarter of what it was.

• The same.

• Quadrupled.

The definition of lift is:

• The aerodynamic force which acts perpendicular to the chord line of the aerofoil.

• The aerodynamic force that results from the pressure differentials about an aerofoil.

• The aerodynamic force which acts perpendicular to the upper surface of the aerofoil.

• The aerodynamic force which acts at 90° to the relative airflow.

Resistance, or skin friction, due to the viscosity of the air as it passes along the surface of a wing, is a type of:

• Induced drag.

• Form drag.

• Parasite drag.

• Interference drag.

As airspeed increases induced drag _____, parasite drag _____, and total drag _____:

• Increases, Increases, Increases

• Increases, Decreases, Increases then decreases

• Decreases, Decreases, Decreases

• Decreases, Increases, Decreases then increases

The maximum value of the coefficient of lift is found at an angle of attack of approximately:

• Minus 4 degrees.

• 0 degrees.

• 4 to 6 degrees.

• 16 degrees.

An aerofoil section is designed to produce lift resulting from a difference in the:

• Negative air pressure below and a vacuum above the surface.

• Higher air pressure below the surface and lower air pressure above the surface.

• Vacuum below the surface and greater air pressure above the surface.

• Higher air pressure at the leading edge than at the trailing edge.

At a given Indicated Air Speed, what effect will an increase in air density have on lift and drag?

• Lift will increase but drag will decrease.

• Lift and drag will increase.

• Lift and drag will decrease.

• Lift and drag will remain the same.

If the Indicated Air Speed of an aircraft is increased from 50 kt to 100 kt, parasite drag will be:

• Four times greater.

• Six times greater.

• Two times greater.

• One quarter as much.

As airspeed increases, induced drag:

• Increases.

• Decreases.

• Is dependant on the weight of the aircraft.

• Remains unchanged.

A positively cambered aerofoil starts to produce lift at an angle of attack of approximately:

• Minus 4 degrees.

• 0 degrees.

• 4 to 6 degrees.

• 16 degrees.