 # PPL test – 8/10 Principles of flight | Explanation

#### 1) The coefficient of lift …

• is proportional to the square of airspeed.
• is zero at symmetric foils at zero angle of attack. (correct answer)
• reaches minimum value at the critical Angle of attack.
• is constantly increasing with increasing AoA.

#### Explanation: #### 2) Yawing is a rotation about:

• The normal axis controlled by the elevator.
• The longitudinal axis controlled by the ailerons.
• The lateral axis controlled by the rudder.
• The vertical axis controlled by the rudder. (correct answer) #### 3) Which drag component is not increasing with raising speed?

• Profile drag.
• Parasite drag. #### 4) The term angle of attack” is defined as the angle”

• formed by the longitudinal axis of the airplane and the relative wind.
• between the wing chord line and the relative wind. (correct answer)
• formed by the longitudinal axis of the airplane and the chord line of the wing.
• between the horizontal tail chord line and the wing chord line.

#### Explanation: See explanation on Wikipedia

#### 5) When does P-factor cause the airplane to yaw to the left?

• When at high airspeeds.
• When at low angles of attack.
• When at high angles of attack.

Explanation:

(P-factor occurs when the airplane is flown at a high angle of attack. The downward-moving blade on the right side of the propeller (as seen from the rear) has a higher angle of attack, which creates higher thrust than the upward moving blade on the left. Thus, the airplane yaws around the vertical axis to the left.

See explanation on Wikipedia