FaA - Aero Coefficients

On an airfoil, the pressure coefficient at the stagnation point is:

• +1

• -1

• 0

• infinite

Below the critical angle of attack, the pressure coefficient on the lower surface of an airfoil is mostly:

• Positive.

• 0

• Negative.

• +1

The aerodynamic centre of an airfoil moves with the angle of attack.

• True

• False

We increase a wing AoA. Assuming we do not exceed the critical AoA, the centre of pressure moves:

• Gradually rearwards.

• Rapidly forwards.

• Rapidly rearwards.

• Gradually forwards.

The aerodynamic centre of a body is defined as:

• The average location of the pressure field.

• The average location of the weight of the body.

• The point about which the pitching moment coefficient is zero.

• The point about which the moment will remain constant as the AoA changes.

As the angle of attack of an airfoil is increased, the adverse pressure gradient on the upper surface is decreased.

• True

• False

Stall occurs at the critical AoA when the lower surface of the aerofoil is predominantly covered in separated flow.

• True

• False

As a wing stalls, the centre of pressure:

• Moves gradually rearwards.

• Moves rapidly rearwards.

• Moves rapidly forwards.

• Moves gradually forwards.

In order to half the stall speed of an aircraft, what would we need to do to the weight of the aircraft?

• Halve the aircraft weight.

• Quadruple the aircraft weight.

• Quarter the aircraft weight.

• Double the aircraft weight.

Increasing the Reynolds number:

• Has no effect on the drag coefficient.

• Has no effect on the lift coefficient.

• Increases Clmax.

• Decreases Clmax.