Theory Of Flight Flashcards
What are the 4 force acting on an airplane? Point them with your hand.
Thrust, drag, lift and weight
Name the 3 laws of newton that make flying possible.
1- A body in motion tends to remain in motion (inertia)
2- A force must be applied to alter the state of uniform motion of a body
3- The application of such a force causes an equal and opposite reaction (pushing air down; airplane want to go up)
Explain the Bernoulli’s principle.
The total energy in any system remain constant (same amount of energy at the beginning and at the end)
The total energy in any system remain constant. According to this, less pressure means and more pressure means:
More speed, less speed.
What is the relative airflow?
The mass of air that is on the front of the plane that the airplane travel on to. Perpendicular to the lift.
What is the angle of attack?
Angle between relative air flow and chord line.
Define what is the chord line.
It is the imaginary line from the middle of the leading edge to the middle of the training edge.
What is the boundary layer over a wing?
The smooth air flowing over the wing.
What is the critical angle of attack?
When the wing is at the maximum lift that it can creat. The airflow over the wing start to get turbulent and start to separate from the wing. When the air detach from the wing, we are experiencing a stall (Stall angle).
Where does the resultant lift appear?
On the center of pressure on the wing.
The increase of pressure under a wing cause lift. What is the name of that lift?
Dynamic lift
The decrease of pressure over a wing can cause lift. What is the name of that lift?
Suction lift
What are the 2 categories of drag that form total drag?
Induced drag and parasite drag
What is the meaning of parasite drag and name the different categories of parasite drag.
Definition: any drag cause by something that doesn’t contribute to lift.
Skin friction drag (profile drag)
Form drag: aerodynamic shape (profil drag)
Interference drag: joint, little place where air doesn’t flow really well
What is the induced drag?
Any drag created by parts that creat that are active in producing lift
Example: the wing creat both lift and drag, this is creating wake turbulence.
Explain wing tip vortices
The air underneath the wing that tends to flow outward and curl over the top of the wing, this creat vortices.
Explain adverse yaw
When you bank and you have more lift on one wing or more drag, this cause the plane to yaw
Name the 2 ailerons solution for adverse yaw
Differential aileron and frise aileron
Explain couple when we talk about forces
When two force are equal and opposite but parallel, rather tan passing trough the same point, they form a couple
What is aspect ratio?
Relation between span and the chord line. The higher ratio you have, the better it glide and the less it have induce drag.
What is the angle of incidence?
Line between the chord and longitudinal axis of the plane, define our angle of attack before having enough speed.
Where do the stall begins?
At the wing root and has the angle of attack increase, the stall move to the wing tip
What is the purpose of wing fence?
Lower stall speed and better manoeuvrability at lower speed
Slots is a …. Opening
Fix and it improve the airflow
Slats is a … and … slots
Closed and open that improve the airflow
What is the role of spoilers?
Destroy the lift when landing or help the aileron in flight
What is the role of speed brake
Creat drag without affecting the wing lift
Flaps produce lift from … to … degree
1 to 20
Flaps produce drag from … to … degree
20 to 40
