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Flight Class 22-13 > Aerodynamics > Flashcards

Aerodynamics Flashcards

1
Q

Define Vector

A

A Vector is a quantity that represents magnitude and direction. Can be divided into separate components- vertical and horizontal

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2
Q

Define: Air Density

A

Mass per unit volume. Air density is air particles within a given volume

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3
Q

Define: moment

A

A moment is a rotational force around a point or axis

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4
Q

State the requirements for an airplane to be in equilibrium flight

A

Equilibrium exists when the sum of all forces and the sum of the moments around the center of gravity equals zero

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5
Q

Define relative wind

A

relative wind is the airflow experienced by the aircraft as it flies through the air. It is always equal and opposite to the flight path. The relative wind may arise from the motion of the body, motion of the air, or from both

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6
Q

State the requirements for an airplane to be in trimmed flight

A

Trimmed flight is a condition that exists when the sum of the moments acting around the center of gravity are equal to zero

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7
Q

Describe the relationship between temperature and altitude

A

Temperature drops 2C per 1000’ gained in altitude

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8
Q

State the General Gas Law

A
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9
Q

Explain the continuity equation given cross-sectional area and velocity

A

A1V1 = A2V2

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10
Q

Explain:

Indicated Air Speed

A

IAS

PT= PS + q

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11
Q

Calibrated airspeed

A

CAS is IAS corrected for position/instrument error

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12
Q

Equivalent airspeed

A

EAS is CAS corrected for compressibility effects

This is only used when flying at supersonic speeds

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13
Q

True Airspeed

A

TAS is EAS corrected for density

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14
Q

Ground Speed

A

Ground speed is TAS Corrected for wind

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15
Q

Mean Camber Line

A

Line from leading edge to trailing edge, halfway between upper and lower surface of the airfoil

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16
Q

Define Chord

A

Chord is the precise measurement between the leading and trailing edges

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17
Q

Define Camber and camber types

A

Camber: maximum distance between the mean camber line and the chordline, measured perpendicular to the chordline

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18
Q

Define: wingspan

A

wingspan is measured tip to tip

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19
Q

Define: wing area

A

Wing area is

the apparent surface area of a wing from tip to tip including the area within the fuselage, hull, or nacelles

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20
Q

Define: chordwise airflow

A

Chordwise airflow: airflowing at right angles to the LE

only air flow that accelerates over the wing and the only type of airflow that produces lift

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21
Q

Define: spanwise airflow

A

spanwise airflow:

airflow that travels along the span of the wing parallel to the leading edge.

normally root to tip

DOES NOT PRODUCE LIFT

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22
Q

Define: pitch attitude

A

angle between the airplane’s longitudinal axis and the horizon

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23
Q

Define: flight path

A

flight path is the path described by the center of gravity as it moves through an air mass

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24
Q

Define: Relative Wind

A

relative wind is the airflow the airplane experiences as it moves through the air. It is equal in magnitude and opposite in direction to the flight path

25
Q

Define: Angle of Attack

A

AOA is the angle between the relative wind and the chordline of an airfoil

26
Q

Define: Angle of Incidence

A

AOI is the angle between the longitudinal axis of the airplane and the chordline of the wing

27
Q

Define the Center of Gravity

A

CG is the point at which all weight is considered to be concentrated and about which all forces and moments are measured

28
Q

Define the Aerodynamic Center

A

Aerodynamic center is the point along the chordline around which all changes in the aerodynamic force take place.

located about 25% of the length of the chordline from the leading edge. It is also the point of maximum thickness of the airfoil or where we have the most positive camber

29
Q

What are the components of CL

A

Components that make up the coefficient of lift are:

compressibility

Aspect Ratio

Viscosity

AOA

Camber

*the shape of the airfoil and the AOA are the only 2 which can be controlled by the pilot

30
Q

Define CLMAX

A

CLMAX is the maximum lift coefficient. It is dependent on the AOA. The CLMAX will be the most effective angle of attack

31
Q

Define: Parasite Drag

A

Drag that is not associated with lift.

2 kinds:

Form: results from the disruption of streamline flow (shape and velocity important factors)

(think of an eddy- the laminar airflow separation from the surface creates a low pressure wake behind the object which pulls the object backward and slows down forward motion)

Friction: any drag caused by the surface of the object itself

minimize with streamlining and clean, well kept, smooth surfaces

Dp = q f where f= the equivalent parasite area (or the size of a flat plate which would generate the same amount of drag)

32
Q

Define: Induced drag

A

Induced drag IS associated with the production of lift

comes from the rotated total lift due to the change in the relative wind produced by the wingtip vortices (extra downwash)

*its the horizontal component of the Rotated Total Lift vector

33
Q

Describe factors affecting induced drag

A

Induced drag is affected by angle of attack and airspeed.

the slower the speed, the greater the AOA is needed to produce lift. With greater AOA, you end up with more lateral movement of air to the wingtip creating greater wingtip vortices which will increase the downwash. The increased downwash will further recline the total lift vector creating increased Di

Higher velocity, lower drag

34
Q

List prevention methods of induced drag

A

Prevention of induced drag:

ground effect

wingtip devices

35
Q

What is L/DMAX

A

L/DMAX is the point at which the parasite and induced drag are equal creating minimum total drag

this is your most efficient angle of attack (Max range)

L/D Max is the point where the ratio of lift to drag is the greatest

36
Q

Define: Boundary Layer

A

Boundary layer-

Thin layer of airflow over an airfoil that consists of laminar and turbulent flow

laminar flow: moves smoothly with little friction

turbulent: disorganized with large amounts of friction

37
Q

Define: Stall

A

A stall is a condition of flight in which an increase in AOA will result in a decrease in CL.

happens at AOAs greater than the CLMAXAOA

38
Q

Describe the factors necessary for an airplane to spin

A

spins happen with uncoordinated stalls (stall + yaw)

inside wing has a higher AOA and CD than the outside wing

therefore, the inside wing (aka downgoing wing) has lower CL and does not produce lift

39
Q

Describe the actions necessary to recover from a spin

A

To recover from a spin (PARE)

Power to idle

Neutralize Ailerons

Opposite Rudder

Forward Elevator to break stall

40
Q

Define: maximum angle of climb

A

AOC is maximizing altitude while minimizing distance traveled

useful to clear obstacles

41
Q

Define: maximum rate of climb

A

ROC is maximizing altitude while minimizing time

Get to an altitude as quickly as possible

42
Q

Define maximum range

A

Max range- maximum distance traveled for a given amount of fuel

43
Q

Define Maximum endurance

A

Max endurance:

maximum time airborne for a given amount of fuel

occurs at the bottom of the power curve

higher altitudes have better engine performance which decreases the amount of fuel needed

44
Q

Define: max glide range

A

Max glide range:

max distance traveled in a glide

the minimum angle of descent occurs at L/DMAX

45
Q

Define: maximum glide endurance

A

Max glide endurance

minimum RATE of descent occurs at the bottom of the power curve

46
Q

What are the regions of normal and reverse command on the power curve

A

Normal Command: occurs to the right of Max END on a power curve

Reverse command: to the left of Max END on the power curve

flying slower than the max endurance you need to increase power

47
Q

Describe a slipping turn

A

Slipping turn:

Nose is outside of the turn

increased radius

decreased rate

ball is same side of turn needle

48
Q

Describe a skidding turn

A

Skidding turn:

nose is inside

decreased radius

increased rate

ball is opposite of turn needle

dangerous!

49
Q

what is P-factor?

what is slipstream swirl?

how does the pilot compensate?

A

P-Factor: yawing moment caused by one side of the prop

slipstream swirl: the corkscrew airflow traveling around the fuselage and impacting the left side of the vertical stab

greatest at low airspeeds and high power settings

both cause the nose to yaw left so use your right rudder to compensate

50
Q

Define: limit load

A

limit load

max load factor anticipated in normal operation and that can be sustained without risk of permanent deformation

51
Q

Define: ultimate load

A

Ultimate load:

maximum load factor that can be sustained without structural failure and is 1.5x the limit load

52
Q

Define: wind shear

A

Wind shear is a suddent change in wind direction and/or speed over a short distance

53
Q

What is the difference in speed between a power on stall and power off stall?

A

A power on stall still has some component of lift to offset the weight of the airplane. Therefore, stall speeds will be lower in a power on stall

54
Q

What is the Max Endurance on the power curve?

A

Max endurance on the power curve is the max amount of time that the airplane can remain airborne on a given amount of fuel. This is the lowest point on the power curve.

55
Q

Where is the highest AOA located on the power curve

A

The higest AOA is located to the left side of the power curve

56
Q

What is the relationship between velocity and throttle (power) in the region of normal comand?

A

In the region of normal command: to increase velocity you must increase the power

the inverse is true for the region of reverse command

57
Q

what is the equation for distance for take off

A
58
Q

what is the equation for take off velocity?

A
59
Q

what is the recovery for a stall?

A

Relax- relax back pressure slightly to decrease AOA and level plane (bring nose down)

Max- smoothly advance throttle to full power

Level- level wings to the horizon

Ball- apply rudder as necessary (usually Right rudder) to center the ball

Flight Class 22-13 (11 decks)

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