Question

The aerodynamic centre of an aerofoil is defined as the point

• A. Where lift becomes zero
• B. Where pressure is maximum
• C. About which pitching moment is independent of angle of attack
• D. About which sum of all the forces are equal to zero

Hint:

For a subsonic aerofoil, \[ \boxed{ \text{Aerodynamic Centre}=0.25c } \] and the pitching moment about this point is nearly constant with changes in angle of attack.

Answer 1

The Correct Option is C

Step 1: Recall the definition of aerodynamic centre. The aerodynamic centre is the point on an aerofoil about which the pitching moment remains nearly constant as the angle of attack changes.

Step 2: Identify the correct statement. Hence, \[ \boxed{ \text{Pitching moment about the aerodynamic centre is independent of angle of attack.} } \] Therefore, \[ \boxed{\text{About which pitching moment is independent of angle of attack}} \] is the correct answer. Thus, \[ \boxed{(C)} \] is the correct answer.