SPC Basic Aerodynamics Principles 3 — Questions and Answers
Question 1: During a coordinated turn at 60 degrees of bank, the load factor is approximately:
- 1.0 G
- 1.4 G
- 2.0 G (Correct answer)
- 3.0 G
Correct answer: 2.0 G
A 60-degree banked coordinated turn produces a load factor of 2.0 G because the vertical component of lift must still support the aircraft's full weight.
Question 2: What happens to the stall speed of an aircraft during a level, coordinated 60-degree banked turn?
- Stall speed decreases because the wing generates more lift
- Stall speed remains the same as in level flight
- Stall speed increases because of the higher load factor (Correct answer)
- Stall speed increases only if flaps are extended
Correct answer: Stall speed increases because of the higher load factor
Stall speed increases in a banked turn because the higher load factor requires greater angle of attack to maintain altitude, reaching the critical angle sooner.
Question 3: The Magnus effect in aerodynamics refers to:
- Pressure increase ahead of a wing at high angles of attack
- Lift generated by a spinning cylinder or sphere in an airstream (Correct answer)
- Boundary layer turbulence caused by surface roughness
- Drag reduction by streamlining the fuselage
Correct answer: Lift generated by a spinning cylinder or sphere in an airstream
The Magnus effect describes the aerodynamic lift produced when a spinning object moves through a fluid, as the spin creates unequal pressure on opposite sides.
Question 4: What is the purpose of wing washout (geometric twist)?
- To increase the wing's overall lift coefficient
- To ensure the wing root stalls before the wingtip, maintaining aileron effectiveness (Correct answer)
- To reduce structural weight by tapering the wing
- To decrease induced drag at cruise speeds
Correct answer: To ensure the wing root stalls before the wingtip, maintaining aileron effectiveness
Washout reduces the angle of incidence toward the wingtip so the root reaches its critical angle first, keeping the ailerons effective during an impending stall.
Question 5: Aspect ratio of a wing is defined as:
- Wing span divided by mean chord length (Correct answer)
- Wing area divided by span
- Maximum thickness divided by chord length
- Taper ratio divided by sweep angle
Correct answer: Wing span divided by mean chord length
Aspect ratio = wingspan ÷ mean chord (or wingspan² ÷ wing area), and higher aspect ratios reduce induced drag.
Question 6: Which condition produces the greatest induced drag?
- High speed, low angle of attack
- Low speed, high angle of attack (Correct answer)
- High speed, high angle of attack
- Low speed, low angle of attack
Correct answer: Low speed, high angle of attack
Induced drag is greatest at high angles of attack and low speeds because the pressure differential between the wing surfaces is maximized, strengthening wingtip vortices.
Question 7: The boundary layer over a wing is the region of air where:
- Airspeed equals the free-stream velocity
- Viscous effects cause the air velocity to transition from zero at the surface to free-stream speed (Correct answer)
- Turbulent flow first begins due to compressibility
- Pressure reaches its minimum value
Correct answer: Viscous effects cause the air velocity to transition from zero at the surface to free-stream speed
The boundary layer is the thin layer of air next to the wing surface where viscosity causes air velocity to rise from zero (at the surface) to the full free-stream airspeed.
SPC Basic Aerodynamics Principles 3
During a coordinated turn at 60 degrees of bank, the load factor is approximately: