Aerodynamics Flashcards
7 cards from real CPL practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Aerodynamics flashcards as text
What is 'spanwise flow' on a swept wing and what problem does it cause?
Answer: Outboard flow along the span that thickens the boundary layer at the tip, promoting tip stall
Spanwise flow moves air outboard toward the wingtip, causing the boundary layer to thicken there, leading to tip stall and a pitch-up moment.
How does ice accretion on the leading edge affect an aircraft's stall characteristics?
Answer: Stall may occur at a significantly lower angle of attack with reduced warning
Ice disrupts smooth airflow over the leading edge, causing early boundary layer separation at lower angles of attack and often with reduced aerodynamic warning.
What is the 'P-factor' (asymmetric blade effect) and when is it most pronounced?
Answer: The greater thrust from the descending propeller blade at high angles of attack
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.
What is the aerodynamic principle behind a delta wing at high angles of attack?
Answer: Leading-edge vortices generate additional low-pressure lift on the upper surface
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.
What effect does decreasing air density (high altitude or high temperature) have on true stall speed?
Answer: True stall speed increases while indicated stall speed remains approximately constant
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.
Which characteristic defines a 'supercritical airfoil' used on modern airliners?
Answer: Flatter upper surface that delays shock wave formation and reduces wave drag
Supercritical airfoils have a flatter upper surface that spreads the pressure rise over a longer distance, delaying and weakening shockwave formation in transonic flight.
What does 'adverse yaw' describe, and what control surface is designed to counter it?
Answer: Yaw opposite to the intended turn direction when ailerons are applied, countered by the rudder
Adverse yaw occurs because the rising wing's aileron creates more induced drag, yawing the nose toward the outside of the turn; rudder input corrects it.