CPL Aerodynamics 5

Question 1

What is 'spanwise flow' on a swept wing and what problem does it cause?

Accepted Answer

Outboard flow along the span that thickens the boundary layer at the tip, promoting tip stall

Answer

Spanwise flow moves air outboard toward the wingtip, causing the boundary layer to thicken there, leading to tip stall and a pitch-up moment.

Question 2

How does ice accretion on the leading edge affect an aircraft's stall characteristics?

Accepted Answer

Stall may occur at a significantly lower angle of attack with reduced warning

Answer

Ice disrupts smooth airflow over the leading edge, causing early boundary layer separation at lower angles of attack and often with reduced aerodynamic warning.

Question 3

What is the 'P-factor' (asymmetric blade effect) and when is it most pronounced?

Accepted Answer

The greater thrust from the descending propeller blade at high angles of attack

Answer

At high angles of attack, the descending blade has a greater effective angle of attack and produces more thrust than the ascending blade, yawing the aircraft.

Question 4

What is the aerodynamic principle behind a delta wing at high angles of attack?

Accepted Answer

Leading-edge vortices generate additional low-pressure lift on the upper surface

Answer

Delta wings develop strong leading-edge vortices that create sustained low-pressure areas on the upper surface, providing controlled lift at high angles of attack.

Question 5

What effect does decreasing air density (high altitude or high temperature) have on true stall speed?

Accepted Answer

True stall speed increases while indicated stall speed remains approximately constant

Answer

Stall occurs at a fixed angle of attack and indicated airspeed; as density decreases, the same IAS corresponds to higher TAS, so true stall speed increases.

(CPL) Commercial Pilot Licence Practice Test

(CPL) Commercial Pilot Licence Practice Test

CPL Aerodynamics 5