Theory Of Flight

Question 1

What are the 4 force acting on an airplane? Point them with your hand.

Answer 1

Thrust, drag, lift and weight

Question 2

Name the 3 laws of newton that make flying possible.

Answer 2

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)

Question 3

Explain the Bernoulli’s principle.

Answer 3

The total energy in any system remain constant (same amount of energy at the beginning and at the end)

Question 4

The total energy in any system remain constant. According to this, less pressure means and more pressure means:

Answer 4

More speed, less speed.

Question 5

What is the relative airflow?

Answer 5

The mass of air that is on the front of the plane that the airplane travel on to. Perpendicular to the lift.

Question 6

What is the angle of attack?

Answer 6

Angle between relative air flow and chord line.

Question 7

Define what is the chord line.

Answer 7

It is the imaginary line from the middle of the leading edge to the middle of the training edge.

Question 8

What is the boundary layer over a wing?

Answer 8

The smooth air flowing over the wing.

Question 9

What is the critical angle of attack?

Answer 9

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).

Question 10

Where does the resultant lift appear?

Answer 10

On the center of pressure on the wing.

Question 11

The increase of pressure under a wing cause lift. What is the name of that lift?

Answer 11

Dynamic lift

Question 12

The decrease of pressure over a wing can cause lift. What is the name of that lift?

Answer 12

Suction lift

Question 13

What are the 2 categories of drag that form total drag?

Answer 13

Induced drag and parasite drag

Question 14

What is the meaning of parasite drag and name the different categories of parasite drag.

Answer 14

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

Question 15

What is the induced drag?

Answer 15

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.

Question 16

Explain wing tip vortices

Answer 16

The air underneath the wing that tends to flow outward and curl over the top of the wing, this creat vortices.

Question 17

Explain adverse yaw

Answer 17

When you bank and you have more lift on one wing or more drag, this cause the plane to yaw

Question 18

Name the 2 ailerons solution for adverse yaw

Answer 18

Differential aileron and frise aileron

Question 19

Explain couple when we talk about forces

Answer 19

When two force are equal and opposite but parallel, rather tan passing trough the same point, they form a couple

Question 20

What is aspect ratio?

Answer 20

Relation between span and the chord line. The higher ratio you have, the better it glide and the less it have induce drag.

Question 21

What is the angle of incidence?

Answer 21

Line between the chord and longitudinal axis of the plane, define our angle of attack before having enough speed.

Question 22

Where do the stall begins?

Answer 22

At the wing root and has the angle of attack increase, the stall move to the wing tip

Question 23

What is the purpose of wing fence?

Answer 23

Lower stall speed and better manoeuvrability at lower speed

Question 24

Slots is a …. Opening

Answer 24

Fix and it improve the airflow

Question 25

Slats is a … and … slots

Answer 25

Closed and open that improve the airflow

Question 26

What is the role of spoilers?

Answer 26

Destroy the lift when landing or help the aileron in flight

Question 27

What is the role of speed brake

Answer 27

Creat drag without affecting the wing lift

Question 28

Flaps produce lift from … to … degree

Answer 28

1 to 20

Question 29

Flaps produce drag from … to … degree

Answer 29

20 to 40