# Aerodynamics Flashcards

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1
Q

What is a stall?

A

When the airfoil exceeds the critical angle of attack.

2
Q

What is the angle of attack?

A

It is the angle between the chord line and the relative wind.

3
Q

Lift is always ______________ to the relative wind.
Drag is always ______________ to the relative wind.

A

Perpendicular
Parallel

4
Q

As you increase the angle of attack of the wing, what two things increase?

A

Lift and drag

5
Q

How do you change the lift, drag, and airspeed?

A

By changing the angle of attack of the airfoil

6
Q

What changes the indicated airspeed at which an airplane stalls?

A

Changing the amount of G-forces on the aircraft (weight, load factor, power).

7
Q

As speed increases, what happens to parasite drag?

A

It increases (directly proportional)

8
Q

As speed increases, what happens to induced drag?

A

It decreases (indirectly proportional)

9
Q

If you double the speed of the aircraft, what happens to parasite drag?

A

10
Q

Flight at Max L/D gets you what two things?

A

Maximum range and maximum glide

11
Q

What happens to the Max L/D speed as weight decreases?

A

The Max L/D speed decreases

12
Q

Why do you have geometric pitch (twisting) in a propeller?

A

In order to maintain a constant angle of attack throughout the length of the blade.

13
Q

To maintain maximum range with a tailwind, what would you do?

A

Decrease the power and decrease the airspeed.

14
Q

Where does the maximum speed in a jet occur on the lift/drag curve?

A

It occurs at a speed greater than Max L/D

15
Q

Where does the maximum rate of climb speed occur in a jet on the lift/drag curve?

A

It occurs at a speed greater than Max L/D

16
Q

Will an upsloping runway increase or decrease the runway length needed?

A

It will increase the runway needed

17
Q

As weight decreases, what happens to the ideal speed for maximum range?

A

It decreases

18
Q

It minimize fuel consumption in a headwind, what should you do?

A

Increase speed

19
Q

Excessive takeoff speeds will cause what to happen in terms of takeoff distance?

A

2% increase in takeoff distance for each 1% in excessive takeoff speed.

20
Q

Weight increase of 10% will cause the landing distance to increase by how much?

A

10% (10 for 10)

21
Q

A headwind of 10% of takeoff airspeed will decrease the takeoff distance by how much?

A

22
Q

A rule of thumb, an increase of 1,000 feet in density altitude will increase takeoff distance by how much?

A

7%

23
Q

What is more sensitive to higher density altitude? Turbojet or reciprocating?

A

Turbojet

24
Q

The amount of load factor during a turn depends on what?

A

The angle of bank

25
Q

What is the equation for load factor?

A

Lift / Weight

26
Q

Does load factor increase with an increase in airspeed if the angle of bank is not changed?

A

NO

27
Q

What does positive static stability mean?
What does neutral static stability mean?
What does negative static stability mean?

A

The aircraft returns to its original orientation over time.
The aircraft stays in the orientation that you put it in.
The aircraft continues to move away from the original orientation

28
Q

What is longitudinal dynamic instability?

A

The aircraft oscillations continue to get worse and worse.

29
Q

What will happen if you load an aircraft at the aft CG limit? (3 things)

A
• Lower stalling speed
• Higher cruising speed
• Least stability
30
Q

Are outboard ailerons primary flight controls? What are they used for?

A

Yes. They are used for flight at low speeds.

31
Q

What is a control tab?

A

It is used to move control surfaces when you have manual reversion (loss of hydraulic power)

32
Q

What is a servo tab?

A

It moves in a direction opposite of the control surface to help you move the control surface.

33
Q

What is an anti servo tab?

A

It move in the same direction as the control surface to hinder the movement of the control surface.

34
Q

What are the three types of flight controls?

A

Primary (ailerons, rudder, elevator)
Secondary (trim tabs, servo tabs)
Auxiliary (leading edge devices, high lift devices)

35
Q

What do high lift devices do?

A

They increase the lift at slow speeds

36
Q

What is the purpose of a leading edge flaps?

A

Increase the camber of the wing in order to prevent flow seperation.

37
Q

What is the only difference between a slat and a slot?

A

A slot is permanent, a slat is movable

38
Q

What do swept wings do in terms of flap effectiveness?

A

The swept wing causes a reduction in the effectiveness of flaps.

39
Q

Aerodynamic braking is only effective to what percentage of landing speed?

A

60-70% of landing speed

40
Q

Vmu

A

Minimum unstick speed (minimum speed that you can get the aircraft off the ground)

41
Q

Vs

A

Stalling speed clean

42
Q

Vso

A

Stalling speed in landing configuration

43
Q

Vc

A

Design cruise speed

44
Q

Vmo/Mmo

A

Maximum operating limits of the aircraft (indicated airspeed)

45
Q

Critical mach number

A

Highest speed without super sonic flow.

46
Q

What is the subsonic flight regimes?
What is the trans sonic flight regimes?

A

Below .75
Between .75 and 1.0

47
Q

Where does drag rise usually occur?

A

5 to 10% above the critical mach number

48
Q

What is the advantage of a swept wing aircraft?

A

It has a higher critical mach number

49
Q

What is the disadvantage of the swept wing aircraft?

A

Tend to lose aileron control at the wing tips.

50
Q

What is shock stall?

A

Some part of the wing stall when the air goes supersonic.

51
Q

What is Mach tuck?

A

The center of pressure moving backwards on the wing causing the nose to dip.

52
Q

What are vortex generators?

A

Prevent shock induced separation of air from the wing.

53
Q

For significant benefit the wing must be swept back how many degrees?

A

30 to 35 degrees

54
Q

What does the blue radial line mean?

A

Maximum single engine rate of climb speed

55
Q

Vyse

A

Maximum single engine rate of climb speed

56
Q

If you lose on engine, in a multi engine aircraft, how much of your climb rate would you lose?

A

More than 50%

57
Q

Which is the critical engine on a multiengine prop plane?

A

The left engine.

58
Q

If you are operating at Vmc, what is the only thing that you can expect to maintain?

A

59
Q

Vmc ______________ with altitude

A

decreases

60
Q

Vmc ______________ with a more forward CG

A

decreases