Aviation Aerodynamics & Aircraft Performance 1 — Questions and Answers
Question 1: Which of the four aerodynamic forces acts opposite to the direction of flight?
- Lift
- Thrust
- Drag (Correct answer)
- Weight
Correct answer: Drag
Drag opposes the direction of flight and must be overcome by thrust to maintain airspeed.
Question 2: According to Bernoulli's principle, what happens to air pressure as airspeed over a wing increases?
- Pressure increases
- Pressure decreases (Correct answer)
- Pressure remains constant
- Pressure fluctuates randomly
Correct answer: Pressure decreases
Bernoulli's principle states that as fluid velocity increases, static pressure decreases, which generates lift on the upper wing surface.
Question 3: What is the angle of attack?
- The angle between the runway and the aircraft's nose
- The angle between the chord line and the relative wind (Correct answer)
- The angle between the aircraft and the horizon
- The pitch angle of the propeller blades
Correct answer: The angle between the chord line and the relative wind
Angle of attack is the angle between the wing's chord line and the relative wind (direction of oncoming airflow).
Question 4: What occurs when a wing exceeds its critical angle of attack?
- Lift doubles instantly
- The aircraft enters a spin automatically
- The wing stalls and lift decreases dramatically (Correct answer)
- Drag drops to zero
Correct answer: The wing stalls and lift decreases dramatically
Exceeding the critical angle of attack causes airflow to separate from the upper wing surface, resulting in a sudden and dramatic loss of lift (stall).
Question 5: What type of drag is caused by the generation of lift?
- Parasite drag
- Form drag
- Induced drag (Correct answer)
- Profile drag
Correct answer: Induced drag
Induced drag is a byproduct of lift generation; it results from wingtip vortices and increases as the angle of attack increases.
Question 6: As altitude increases, how does air density affect aircraft performance?
- Denser air improves engine power and lift equally
- Thinner air reduces engine power and requires higher true airspeed to maintain lift (Correct answer)
- Performance is unaffected because indicated airspeed stays the same
- Lift increases because the wings work more efficiently
Correct answer: Thinner air reduces engine power and requires higher true airspeed to maintain lift
Higher altitude means lower air density, which reduces engine power output and requires a higher true airspeed to generate the same lift, degrading overall performance.
Question 7: What is the primary purpose of an aircraft's flaps?
- To increase cruise speed
- To increase lift and drag for slower flight and shorter landings (Correct answer)
- To reduce induced drag during climb
- To provide roll control at low speeds
Correct answer: To increase lift and drag for slower flight and shorter landings
Flaps increase both lift and drag, enabling slower approach and landing speeds and reducing the runway distance required.
Aviation Aerodynamics & Aircraft Performance 1
Which of the four aerodynamic forces acts opposite to the direction of flight?