FREE CPL Aerodynamics Questions and Answers
The net effect of all forces acting on an aircraft wing are:
Explanation:
It is called the total reaction.
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?
Explanation:
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.
Lift is produced as a result of:
Explanation:
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.
Bernoulli's principle found static pressure:
Explanation:
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.
When applying Bernoulli's theory to an aircraft wing it is logical to say:
Explanation:
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.
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."
What are the effects of extended ailerons?
Explanation:
Extended ailerons are designed to protrude past the trailing edge of the wing and produce additional lift during slow flight.
To achieve the greatest range in a single Cessna 182, the power must:
Explanation:
The speed of minimum drag provides the greatest range.
To achieve an emergency off-field landing with the minimum kinetic energy into a tea tree plantation, the PIC must:
Explanation:
This question tests your knowledge of kinetic energy. The lower the speed, the lower the kinetic energy.
What is the purpose of a spoiler on an aircraft?
Explanation:
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.
The greatest fuel range for an aircraft will be achieved at:
Explanation:
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.
The diagram below is a rough incomplete graph of induced drag.
Explanation:
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.