POF - Aerofoil Pressure Distribution

Question 1

What does the magnitude and direction of the Total Reaction depend on?

Answer 1

It depends on:
• The pressure distribution around the aerofoil.
• The overall area of the aerofoil.

Question 2

What does the pressure distribution depend on?

Answer 2

• the speed of the airflow
• the angle of attack
• the camber

Question 3

What happens to the CP point when a positive cambered aerofoil increases its Angle of Attack?

Answer 3

It will increase the total reaction and will move the CP point forward.

Question 4

What happens when you increase the angle of attack on a symmetrical Aerofoil?

Answer 4

The magnitude of the total reaction will increase however the CP point will stay the same.

Question 5

What will happen if you increase the camber?

Answer 5

The pressure differential between the upper and lower surfaces of the aerofoil will increase.

Question 6

What does the magnitude of the pressure created vary with?

Answer 6

Speed of the air flow - the greater the speed, the greater the pressure change.

Question 7

How do you calculate surface pressure?

Answer 7

The formula is:

Surface Pressure (Pa) = Force (N) / Area (m^2)

Question 8

What does the co-efficient of force depend on?

Answer 8

1. Dynamic Pressure (q)
2. Surface Area (S)
3. The camber & Angle of Attack (Cf)

Question 9

Does the upper surface of a wing have low or high pressure?

Answer 9

The upper surface of a wing has low pressure due to velocity increasing