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

Inboard flow that reduces tip vortices and improves efficiency

Answer

Turbulent flow along the chord that reduces lift on swept wings

Answer

Reversed flow behind the shock wave during transonic cruise

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

Stall occurs at a higher angle of attack with more warning buffet

Answer

Ice increases stall speed but not the stall angle of attack

Answer

Ice improves turbulent flow and delays stall

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

Gyroscopic precession occurring during climbs and turns

Answer

Propeller torque reaction that rolls the aircraft left

Answer

Spiraling slipstream effect at cruise power

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

Laminar flow over the entire delta surface maintains lift efficiently

Answer

The large chord prevents separation at any angle of attack

Answer

Reduced aspect ratio eliminates induced drag entirely

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

Both true and indicated stall speeds increase equally

Answer

True stall speed decreases due to reduced drag

Answer

Indicated stall speed increases at high altitude

Question 6

Which characteristic defines a 'supercritical airfoil' used on modern airliners?

Accepted Answer

Flatter upper surface that delays shock wave formation and reduces wave drag

Answer

Symmetrical profile that operates efficiently at all speeds

Answer

Higher camber for maximum lift at low speeds

Answer

Thicker trailing edge that increases structural strength only

Question 7

What does 'adverse yaw' describe, and what control surface is designed to counter it?

Accepted Answer

Yaw opposite to the intended turn direction when ailerons are applied, countered by the rudder

Answer

Pitch-up tendency during roll, countered by elevators

Answer

Yaw toward the lowered aileron corrected by spoilers only

Answer

Roll coupling with yaw inputs, corrected by differential elevator