Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Ground School - Aviation > Theory of flight > Flashcards

Theory of flight Flashcards

1
Q

Bernoulli’s Principle

A

“The total energy in any system remains constant.”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Newton’s 1st Law:

A

A body (or gas) in motion, tends to stay in motion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Newton’s 2nd Law:

A

A force must be applied to alter the state of uniform motion of a body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Newton’s 3rd Law:

A

For every action there is an equal and opposite reaction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Newton’s Laws in Action (example of each)

A
  • -1st Law – Air flows over an airfoil (wing) and inertia causes it to remain in motion.
  • -2nd Law – Introducing the airfoil into the airflow alters the flow of air.
  • -3rd Law – The pressure exerted on the airflow creates an equal and opposite reaction. This reaction is Lift.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Camber

A

The camber of the above airfoil can be seen in its profile or thickness. The average thickness of the wing is known as the Mean Camber.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Chord

A

The line connecting the leading and trailing edge of the airfoil is known as the Chord Line.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Angle of Incidence

A

The wing of an airplane is permanently affixed to the fuselage at a slight positive angle. This angle between the chord line and the longitudinal axis of the airplane is called the Angle of Incidence.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Angle of Attack

A

The angle between the chord line and the relative airflow is the Angle of Attack.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Center of Pressure

A

The sum of all lift generated by the airfoil is said to act through a theoretical point called the Center of Pressure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

As the angle of attack increases what happens to the center of pressure?

A

moves forward.

& as the angle of attack decreases the center of pressure moves back (aka: aft)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

2 types of drag:

A
  • Parasite Drag

* Induced Drag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Parasitic Drag includes:

A
  • Form Drag – the resistance of the shape of the aircraft colliding head on with the relative airflow.
  • Skin Friction – the tendency of air to cling to the surface of the aircraft.
  • Interference Drag – caused by the collision of differing streams of airflow as it flows over the structure of the airplane, (for example, airflow over the wings mixing with airflow around the fuselage.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Induced Drag includes:

A

created by the wing as a byproduct of lift
–can not be eliminated
Ex: Wing-Tip Vortices

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

• Drag Relationship

A

As airspeed is increased, more and more air molecules collide with the aircraft. = increase in parasite drag.

As airspeed is decreased, the wing is flown at an increasingly higher angle of attack. This displaces more air = increase in induced drag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Lift/Drag Max

A

the angle of attack that creates the most lift for the minimum amount of total drag.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Maximum Endurance

A

minimum amount of power is required to maintain altitude. From this point, an increase OR decrease in airspeed requires an increase in power. This is simply because an airplane needs to be moving to fly.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Weight

A

the force acting downward towards the centre of the earth as a result of gravity.

–act through the Center of Gravity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Equilibrium

A

LIFT = WEIGHT and THRUST = DRAG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

An airplane in in Equilibrium will

A

maintain a constant, un-accelerated movement, (such as straight and level, constant speed climb or descent).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Lift always acts at a 90 degree angle to the ______

A

chord of the wing. In a turn, lift is inclined away from the vertical.

22
Q

Consequently, in a turn, lift is divided into

A

vertical and horizontal components

  • -vertical component will decrease with an increase in angle of attack.
  • -Therefore, more lift is required in a turn to maintain speed and altitude.
  • -Without corrective action to increase lift (increasing the angle of attack and power), an aircraft in a turn will lose altitude, airspeed, or usually both.
23
Q

Forces in a Turn

A

horizontal component = Centripetal Force.

–Lift must be great enough to counter both weight and Centrifugal Force

24
Q

Load Factor

A
  • -the effective (or perceived) weight of the aircraft.
  • -measured in “G’s” - One “G” equals 1 gravity
  • -Negative “G’s” = floating & + = pushing into seat.
25
Q

How many G’s on a 20 degree turn?

A

1.06g

26
Q

How many G’s on a 40 degree turn?

A

1.31g

27
Q

How many G’s on a 60 degree turn

A

2g

28
Q

How many G’s on a 80 degree turn?

A

5.76g

29
Q

Boundary Layer

A

thin layer of air lying over the wing surface.

  • -flows smoothly = Laminar Flow.
  • -point at which the laminar layer begins to break away = Transition Point
  • -transition point moves forward with increasing speed or angle of attack.
  • -rough flow = turbulent layer
30
Q

Stalls

A

angle of attack increases, the transition point (where turbulent airflow breaks away from the wing) and the centre of pressure move forward.

Due to the lack of laminar flow, the wing loses its capability to produce lift. This condition is called a stall.

31
Q

A wing will stall when the critical angle of attack is exceeded. This can happen:

A

At any Airspeed
At any Power Setting
At any Attitude
At any Weight

32
Q

Factors Affecting a Stall

A
  • -weight
  • -centre of gravity
  • -turbulance
  • -flaps
  • -contamination
  • -turns
33
Q

How does weight affect stalls?

A
  • -heavier the plane = more lift is required
  • -must be flown at a higher angle of attack = closer to the critical angle of attack
  • -airplane will stall at a higher airspeed.
34
Q

How does Center of Gravity affect stalls?

A
  • -forward center of gravity = higher stall speed.

- -aft center of gravity = lower stall speed.

35
Q

How does Turbulence affect stalls?

A

Gusts of wind can abruptly change the angle of attack, potentially exceeding the critical angle and inducing a stall at higher airspeeds.

36
Q

How does Flaps affect stalls?

A

Flaps increase the lift potential of a wing resulting in a lower stall speed

37
Q

How does Wing Contamination affect stalls?

A

Frost or ice alter the smooth air flow over the wing, causing the separation point to move much further forward than normal.
–stall at much higher airspeeds.

38
Q

How does Turns affect stalls?

A
  • -angle of bank increases = more lift is required to maintain level flight.
  • -Angle of attack must be increased to bring the wing closer to the critical angle.
39
Q

Laminar Flow Airfoil

A

•Laminar flow profiles were developed for higher speeds and better boundary layer control (less drag)

  • transition point to turbulent flow is further back
  • con = stall more abruptly
40
Q

Planform

A

Planform is the shape of the wing as seen from above.

41
Q

Aspect Ratio

A

relationship between a wings length and its width

aka: wing span and Mean Aerodynamic Chord

42
Q

A wing with high aspect ratio =

A

generates more lift with less induced drag

Ex: glider/low power

43
Q

wing with low aspect ratio =

A

greater maneuverability.

Ex: fighter aircraft that produce a large amount of thrust.

44
Q

Dihedral

A
  • -upward angle of the wing from the horizontal ~5degree

- -helps achieve greater roll stability.

45
Q

Anhedral.

A

opposite of dihedral - downward angle

greater maneuverability

46
Q

Wash-Out

A

twist in the wing, giving less incidence at the wing than at the root.
= better stall characteristics

47
Q

Slats

A

Slats are moveable auxiliary airfoils that extend out ahead of the leading edge
–high angles of attack, slats are automatically pulled out by the low air pressure above the leading edge

48
Q

Slots

A

Slots are fixed passageways allowing air to flow through them at low speeds and improving the laminar
flow over the wing.

49
Q

What is the difference between Slats and Slots

A

Slats are moveable & Slots are fixed

50
Q

Wing Fences

A

Wing fences are fin like vertical surfaces attached to the wing. They help control
airflow over specific areas of the wing.

51
Q

Stall Strips

A

Are installed on the wing root of some airplanes to cause an earlier stall at the wing root, (similar to wash-out) while other areas of the wing remain effective.

52
Q

Vortex Generators

A

are designed to re-energize the boundary layer and delay a stall in slow flight.

Ground School - Aviation (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions