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Commercial Knowledge (some) > Aerodynamics/ CG > Flashcards

Aerodynamics/ CG Flashcards

1
Q

What is Stability?

A

Stability is an aircraft’s ability to maintain/Return to its original flight path.

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2
Q

What are the types of static stability?

A

Positive
Neutral
Negative

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3
Q

What is static stability?

A

A aircraft’s initial tendencies

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4
Q

What is dynamic stability?

A

A aircraft’s tendencies over time

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5
Q

What are the types of dynamic Stability?

A

Positive
Neutral
Negative

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6
Q

What is Positive Static Stability?

A

The initial tendency to return to an undisturbed state after a disturbance.

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7
Q

What is Neutral Static Stability?

A

Initial tendency to stay in new attitude when disturbed.

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8
Q

What is negative static stability?

A

Aircraft’s initial tendency to diverge further when disturbed.

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9
Q

What is positive dynamic stability?

A

The tendency to dampen towards its original position once disturbed.

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10
Q

What is neutral dynamic stability?

A

The oscillations continue in the same motions once disturbed, neither increasing or decreasing.

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11
Q

What is negative neutral stability.

A

The oscillations continue in a worse manner once disturbed?

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12
Q

What are the 4 types of left turning tendencies?

A

•P-factor
•Torque
•Spiraling Slipstream
•Gyroscopic Precession

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13
Q

What is P-Factor?

A

Downward blade is at a higher angle of attack generating more lift on that side. More noticeable during slow climbs at high AOA.

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14
Q

What is the Torque Turning tendency?

A

For every action there is an equal and opposite reaction- prop moves clockwise airplane wants to move counter clockwise.

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15
Q

What is the Spiraling Slipstream turning tendency?

A

Air corkscrews around the airplane pushing on the rudder, pushing aircraft to the left.

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16
Q

What is the Gyroscopic Procession turning tendency?

A

Any force applied to a spinning object will be felt 90 degrees ahead of the turn in the direction it’s spinning.
•when pushing the nose down the tendency is to turn left
•when pulling nose up tendency is to turn right

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17
Q

What is Va?

A

Va is the planes maneuvering speed?

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18
Q

Does Va change with weight? If so why?

A

Yes Va changes with weight because at the same speed as a lighter aircraft a heavier aircraft needs to fly at a higher angle of attack to produce enough lift to counter the aircraft’s weight in level flight.

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19
Q

What is the weight shift computation formula?

A

Weight of cargo moved/ airplane weight= distance CG moved/distance between arm locations(stations)

(Cross multiply)

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20
Q

What is load factor?

A

It is the ratio of the lift provided by the lifting surfaces divided by the total weight of the aircraft.

21
Q

How does Load Factor change?

A

Increases as you increase bank(Gs) because it increases the “load”
60 degrees is 2G so 2000 pounds is now 4000 pounds.

22
Q

What happens when load factor increases?

A

The higher the load factor the higher the stall speed.

23
Q

What is CG?

A

Center of Gravity- The point about which an aircraft would balance if it was possible to suspend it on that point.

24
Q

How do you get CG?

A

Total Aircraft weight decided by Total Moment.

25
Q

How does an aft CG effect a planes flying characteristics?

A

•Less stable
•More performance
•less tail trim drag
•decreases stall speed
The arm between your CG and tail downforces decreases thus making it more unstable.

26
Q

How does a forward CG affect flying characteristics?

A

•More tail down force
•Increased AOA= Increased Drag
•More stable because distance between CG and Tail is greater.
•Stall speed increases

27
Q

What happens to the CG as fuel burns?

A

CG can shift so Calculate both takeoff and landing CG.

28
Q

What is a stall?

A

When an aircraft’s wings stop producing lift due to an excessive AOA?

29
Q

What is the Critical Angle of Attack?

A

It is the difference between the relative wind and the cord line.

30
Q

What is Relative wind and Chord line?

A

•Relative wind- direction of the wind relative to the airfoil.
•Chord Line- Imaginary Straight line going through the leading edge to the trailing edge of a wing.

31
Q

What are the Different types of Stalls? (7)

A

•Power-On stall
•Power-Off stall
•Accelerated Stall
•Secondary stall
•Cross-Control stall
•Elevator Trim Stall
•Tail Stall

32
Q

What is a Power-On stall?

A

Stall in Takeoff and Climb configurations.

33
Q

What is a Power-Off stall?

A

Stall in landing and approach configuration.

34
Q

What is an Accelerated Stall?

A

Caused by abrupt or excessive control movements, usually involve a high load factor.

35
Q

What is a Secondary Stall?

A

Usually occurs during an attempt to get out of a stall either by increasing AOA to fast or soon, or by not decreasing angle of attack enough.

36
Q

What is a cross controlled stall?

A

This occurs when flight controls are crossed and a lot of back pressure or slow speed is applied, usually happens on base to final turn. Excessive inside rudder is used to tighten the turn plus back pressure equals a cross controlled stall.

37
Q

What is an Elevator Trim stall?

A

Most likely to occur during a go around, when trim is set for landing. When full power is applied a lot of positive pressure must be applied or the aircraft will want to keep pitching up. Usually a lot of left turning tendency as well and can lead to uncoordinated flight/ a spin.

38
Q

What is a tail stall?

A

Usually more common in tail daggers. Tail stalls before the wings dropping the nose a lot. To recover add lots of back pressure unlike a regular stall.

39
Q

What is a spin?

A

Plane must be stalled first, when one wing is stalled less than the other.

40
Q

What are the phases of a spin? (4)

A

Entry-stalls
Incipient- time from rotation starts to a fully developed spin
Fully developed spin-when one turn to the next is stabilized
Recovery- begins when anti-spin forces overcome the pro-spin forces.

41
Q

What are the different names for high speeds?

A

Subsonic
Transonic
Supersonic
Hypersonic

42
Q

Subsonic flight speed

A

Mach below .75

43
Q

Transonic flight speed

A

Mach from .75 to 1.20

44
Q

Supersonic Flight speed

A

Mach 1.20 to 5.00

45
Q

Hypersonic flight speed

A

Mach above 5.00

46
Q

What is critical Mach number?

A

Speed of an aircraft in which airflow over any part of the aircraft or structure first reaches (but does not exceed) Mach 1.0

47
Q

What is Induced drag VS parasite Drag?

A

Induced Drag- by product of lift being created by the wings.
Parasite Drag-increases with speed, square of the airspeed.

48
Q

Different types of Parasite Drag?

A

Form drag- based on the shape of the airplane and how well it is streamlined.
Interference drag- airflow around one part of the airplane interacts with the airflow around an adjacent part.
Skin friction Drag- Air molecules giving up some of there energy as they contact the skin, smoother the skin= less drag.

Commercial Knowledge (some) (6 decks)

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