Flight Controls Oral Flashcards
Why is it especially important that the leading edge of a wing and the upper surface of the forward half of the wing be kept free of dents and any dirt or contamination?
The air flowing over this portion of the wing must be smooth to produce the maximum amount of lift. If the surface is rough or dirty, the air flow will be distorted and lift will be lost.
What is meant by the angle of incidence of an airplane wing?
The acute angle formed between the chord line of an airfoil and the longitudinal axis of the aircraft on which it is mounted.
What is meant by AOA of an airplane wing?
The acute angle that is formed between the chord line of an airfoil and the direction of the air that strikes it.
What are the four basic forces that act on an aircraft in flight?
Lift, drag, thrust, and gravity.
What causes parasite drag on an airplane?
Friction of air flowing over the surface.
Name the three axes of an airplane and the control that rotates the airplane about each of its three axes.
Longitudinal axis – Ailerons
Lateral axis — Elevators
Vertical axis — Rudder
Does the lift that is produced by the horizontal tail surfaces of an airplane act upward or downward in normal flight?
Downward.
What is the function of lateral dihedral in the wings of an airplane?
Roll stability, longitudinal axis stability.
What is the purpose of a stall strip on an airplane wing?
They distort the air flowing over the top of the wing in the root area at high AOA. They cause the root to stall at a lower AOA than the part of the wing ahead of the Ailerons.
What is the function of a servo tab on an aircraft control surface?
To produce an aerodynamic force on a control surface that aids the pilot in moving the surface.
Why do most high-performance aircraft use slotted flaps?
Slotted flaps can be deflected to a greater AOA than other types of flaps before the airflow over the surface breaks away.
What is the purpose of a movable slat in the leading edge of some airplane wings?
Increase lift and delay stall by automatically moving out of the wing and forming a duct that forces the air back over this upper surface at high AOAs.
Why is it important that the leading edge of a supersonic airplane wing be kept free from dents and damage?
Sharp leading edge allows an oblique shockwave to attack to the airfoil in supersonic flight. If the leading edge is dented or blunt, a normal shock wave will form and slow the air immediately behind it to a subsonic velocity.
What is the purpose of vortex generators on the wing of a high-speed airplane?
To keep shock induction from occurring by pulling high-energy air down to the surface of the wing.
Why are the control cables of large airplanes normally equipped with automatic tension regulators?
To keep cable tension constant as the dimensions of the aircraft’s change since the large amount of aluminum in the aircraft structure contracts so much as its temperature drops in flight that the control cables become dangerously loose.
