Free CPL Aerodynamics Questions and Answers 1 — Questions and Answers
Question 1: What are the effects of extended ailerons?
- produce greater lift and control during slow flight (Correct answer)
- push the low wing down top wing up
- lift top wing up low wing down
- extend the surface flow for high-speed safety
Correct answer: produce greater lift and control during slow flight
Explanation: <br> Extended ailerons are designed to protrude past the trailing edge of the wing and produce additional lift during slow flight.
Question 2: The diagram below is a rough incomplete graph of induced drag.
- When speed is low, induced drag is low, and parasitic drag is low
- When speed is high, induced drag is low, and parasitic drag is low
- When speed is high, induced drag is low, and parasitic drag is high (Correct answer)
- When speed is high, induced drag is high
Correct answer: When speed is high, induced drag is low, and parasitic drag is high
Explanation: <br> Induced drag is directly related to the lift being produced by the wing and hence the angle of attack. At high speed you will have a lower angle of attack otherwise you would climb. This decrease in the angle of attack causes the induced drag to decrease.
Question 3: To achieve an emergency off-field landing with the minimum kinetic energy into a tea tree plantation, the PIC must:
- land at the lowest possible airspeed (Correct answer)
- come in fast and pull back hard to stall 20 feet up
- land at the lowest possible angle of attack
- hit with a wing tip
Correct answer: land at the lowest possible airspeed
Explanation: <br> This question tests your knowledge of kinetic energy. The lower the speed, the lower the kinetic energy.
Question 4: The greatest fuel range for an aircraft will be achieved at:
- the lowest engine rpm
- the lowest angle of attack
- the lowest drag (Correct answer)
- the lowest coefficient of lift
Correct answer: the lowest drag
Explanation: <br> To use the lowest energy you need to produce the lowest force. The force being worked against is a drag. So the lowest drag will require the lowest force to move forward and thus the most movement forward for the least fuel.
Question 5: The net effect of all forces acting on an aircraft wing are:
- the total resultant
- the net reactive coefficient
- the net reaction
- none of these (Correct answer)
Correct answer: none of these
Explanation: <br> It is called the total reaction.
Question 6: What is the purpose of a spoiler on an aircraft?
- helps slow the aircraft, helps descend, and helps stick the aircraft to the ground upon landing (Correct answer)
- helps descend and helps stick the aircraft to the ground upon landing
- helps the aircraft descend and slow down
- provides downforce to stick the aircraft to the runway upon landing
Correct answer: helps slow the aircraft, helps descend, and helps stick the aircraft to the ground upon landing
Explanation: <br> Spoilers on the top surface are also known as lift dumpers. They are primarily used to reduce lift for descent in a controlled manner and to dump lift and increase control upon landing. They also create a lot of drag and thus help slow the aircraft as well. When spoilers are deployed on one wing only, they will roll the aircraft, much like an aileron.
Question 7: To achieve the greatest range in a single Cessna 182, the power must:
- be set to correspond with the minimum induced drag airspeed
- be set to correspond with the minimum parasitic drag airspeed
- be set to correspond with the minimum drag airspeed (Correct answer)
- none of these
Correct answer: be set to correspond with the minimum drag airspeed
Explanation: <br> The speed of minimum drag provides the greatest range.
Question 8: Bernoulli's principle found static pressure:
- stayed the same regardless of the velocity of the air
- increased when the velocity of air increased
- decreased when the velocity of air increased (Correct answer)
- none of these
Correct answer: decreased when the velocity of air increased
Explanation: <br> Bernoulli found that when air moved through a tube, with a smaller mid-section diameter than its ends, as the air velocity increased in the thinner section, the pressure decreased. The total energy remained constant, so as kinetic energy increased with speed, the pressure on the walls decreased.
Question 9: Lift is produced as a result of:
- airflow pushing the wing up
- air pushing from low-pressure to high pressure
- high pressure air underneath a wing and low pressure above a wing (Correct answer)
- low air pressure underneath a wing and high pressure above a wing
Correct answer: high pressure air underneath a wing and low pressure above a wing
Explanation: <br> High pressure wants to go to Low pressure which causes lift. The greater the pressure difference (angle of attack) the greater the lift, until the stalling angle of attack is exceeded.
Question 10: When applying Bernoulli's theory to an aircraft wing it is logical to say:
- the wing will have high pressure on the bottom side and low pressure on the top side
- the wing will have high pressure on the longest side and low pressure on the shortest side
- the wing will have low pressure on the bottom side and high pressure on the top side
- the wing will have low pressure on the longest side and high pressure on the shortest side (Correct answer)
Correct answer: the wing will have low pressure on the longest side and high pressure on the shortest side
Explanation: <br> Using Bernoulli's principle, as kinetic energy increases (airspeed), pressure decreases (because the fluid energy remains constant). Thus air traveling over the longest side of the wing must travel faster and will have a lower pressure. <br> Be careful with this question. Most wings are not symmetrical, meaning the bottom is flat and a curved top. This causes high pressure on the bottom and low pressure on the top but the most correct answer here is "the wing will have low pressure on the longest side and high pressure on the shortest side."
Question 11: Refer to the coefficient of lift curve shown below. At what speed would an aeroplane be operating if flying level at an angle of attack 'X?
- The best climbing speed
- The best lift/drag ratio
- The minimum level of flight speed (Correct answer)
- The maximum level of flight speed
Correct answer: The minimum level of flight speed
Explanation: <br> The point of maximum lift is the stalling speed/angle (Vs). Any faster or slower than the speed will produce a lesser lift coefficient. If the aircraft's AoA is increased beyond "X", the aircraft will stall.
Free CPL Aerodynamics Questions and Answers 1
What are the effects of extended ailerons?