SPC - Student Pilot Certificate Basic Aerodynamics Principles Questions and Answers 1 — Questions and Answers
Question 1: Which of the following describes the relationship between airspeed, angle of attack (AOA), and lift in straight-and-level flight?
- To maintain constant lift, if airspeed decreases, the angle of attack must increase. (Correct answer)
- To maintain constant lift, if airspeed increases, the angle of attack must also increase.
- Angle of attack and airspeed must be held constant to maintain a specific amount of lift.
- Lift is independent of both airspeed and angle of attack.
Correct answer: To maintain constant lift, if airspeed decreases, the angle of attack must increase.
In straight-and-level flight, lift must equal weight. Lift is generated by the movement of air over the wings. If the aircraft slows down (airspeed decreases), the wing must be presented to the oncoming air at a higher angle of attack to generate the same amount of lift required to counteract weight.
Question 2: What are the four fundamental forces acting on an airplane in flight?
- Inertia, Gravity, Pressure, and Momentum
- Lift, Weight, Thrust, and Drag (Correct answer)
- Power, Friction, Buoyancy, and Velocity
- Centrifugal Force, Centripetal Force, Weight, and Lift
Correct answer: Lift, Weight, Thrust, and Drag
The four fundamental forces of flight are lift (the upward force created by the wings), weight (the downward force of gravity), thrust (the forward force from the engine/propeller), and drag (the rearward force of air resistance).
Question 3: A pilot is on final approach for landing and extends the flaps. What is the primary aerodynamic reason for using flaps during this phase of flight?
- To decrease the angle of attack and increase landing speed.
- To increase the wingspan for better roll control.
- To allow the aircraft to fly at a slower airspeed while maintaining sufficient lift. (Correct answer)
- To reduce the overall weight of the aircraft.
Correct answer: To allow the aircraft to fly at a slower airspeed while maintaining sufficient lift.
Extending flaps increases the wing's camber and, in some cases, its surface area. This allows the wing to produce the required lift at a lower airspeed, enabling a slower and steeper approach for landing.
Question 4: According to Bernoulli's Principle, how is lift generated by an airfoil?
- By creating an area of higher pressure above the wing and lower pressure below it.
- By deflecting air downward, which results in an upward reaction force.
- By increasing the density of the air above the wing.
- By creating an area of lower pressure above the wing and higher pressure below it. (Correct answer)
Correct answer: By creating an area of lower pressure above the wing and higher pressure below it.
Bernoulli's Principle states that as the velocity of a fluid (like air) increases, its pressure decreases. The curved shape of an airfoil forces the air flowing over the top to travel a longer distance, and thus faster, than the air flowing underneath. This creates lower pressure above the wing and higher pressure below, resulting in an upward force called lift.
Question 5: The 'critical angle of attack' is the point at which...
- lift is at its maximum and the wing will stall if the angle is increased further. (Correct answer)
- the aircraft experiences the least amount of drag.
- thrust and drag are perfectly equal.
- the aircraft achieves its maximum possible speed.
Correct answer: lift is at its maximum and the wing will stall if the angle is increased further.
The critical angle of attack is the angle at which the wing produces its maximum lift coefficient. If the angle of attack is increased beyond this point, the airflow over the upper surface of the wing will separate, causing a rapid decrease in lift and an increase in drag. This condition is known as a stall.
Question 6: During a climb, what is the relationship between the four forces of flight?
- Thrust equals drag, and lift equals weight.
- Thrust is greater than drag, and lift is greater than weight.
- Thrust is greater than drag, and lift is less than weight. (Correct answer)
- Thrust is less than drag, and lift is greater than weight.
Correct answer: Thrust is greater than drag, and lift is less than weight.
In a steady, constant-rate climb, thrust must be greater than drag to provide the necessary force for climbing. However, because part of the thrust is directed upward (relative to the flight path), lift does not need to fully support the aircraft's weight. Therefore, lift is actually less than weight, and the vertical component of thrust helps to overcome the difference.
SPC - Student Pilot Certificate Basic Aerodynamics Principles Questions and Answers 1
Which of the following describes the relationship between airspeed, angle of attack (AOA), and lift in straight-and-level flight?