Brainscape's Knowledge GenomeTM

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


See full index

M8 R > M8.2 > Flashcards

M8.2 Flashcards

1
Q

What is the definition of aerodynamics?

A

The study of the properties of moving air and the integration between the air and moving bodies

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

What is said about air in the subsonic region?

A

The air is incompressible

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

How are streamlines layered out when there isn’t any disturbance?

A

They’re parallel to each other

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

What does the continuity equation state?

A

The speed of airflow is inversely proportional to the area of cross section

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

What is the equation for the continuity equation?

A

V1 x A1 = V2 x A2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the term diffuser outlet mean?

A

The tube diameter increases and the speed decreases

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

What does the term jet outlet mean?

A

The tube diameter decreases and the speed increases

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

What does Bernoulli’s equation state?

A

Total pressure is always the sum of static pressure and dynamic pressure

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

If airflow speed increases what happens to static pressure and the dynamic pressure?

A

Static pressure decreases and dynamic pressure increases

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

What is up-wash?

A

When some of the lower streamlines get pulled up and over the profile

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

What is down-wash?

A

When the streamlines on top of the profile get pushed down after leaving the profile

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

What happens to lift if you have no differential pressure?

A

You have no lift

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

What is the Magnus effect?

A

Lift caused by rotation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is meant by a profile?

A

The cross section of a wing

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

What is the chord line?

A

It is a straight line from the leading edge to the trailing edge

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

What is the mean camber line?

A

It is a line drawn halfway between the upper and lower surfaces of the profile

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

Why is the mean camber line important?

A

Because it helps determine the aerodynamic characteristics

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

What is the camber?

A

It is the distance between the mean camber line from the chord line

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

Where is the location of max camber?

A

Where the camber is at it widest

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

What is flight path velocity?

A

The speed of the aircraft in a certain direction

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

What is relative wind?

A

The speed and direction of the air acting on the aircraft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What direction does relative wind tend to act in?

A

The opposite to flight path velocity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the angle of attack?

A

The angle of the chord line and relative wind

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the angle of incidence?

A

The angle between the chord line and the longitudinal axis of the aircraft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How is angle of attack denoted?

A

By the symbol of alpha (a)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How is angle of incidence denoted?

A

By the symbol of gamma (Y)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Is the fuselage area included in the wing area?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How is wing area calculated?

A

Wing span X chord line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the root chord?

A

The chord at the root of the aircraft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the tip chord?

A

The chord at the tip of the wing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How is a tapered wing area calculated?

A

Wing span X average chord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the taper ratio?

A

The ratio between tip chord and root chord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How is the aspect ratio calculated?

A
  • wing span / average chord

- wing span squared/ wing area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

How is the sweep angle measured?

A

It is a line from the root to tip taken from 25% of the chord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What direction is a positive sweep?

A

Backwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What direction is a negative sweep?

A

Forwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What happens when the wing gets more swept back?

A

It becomes more stable on the roll axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What will a shock wave cause the aircraft to do?

A

Reduce lift and increase drag on the wing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is it called when the shock wave begins to appear?

A

Critical mach number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is span wise flow?

A

When the airflow is perpendicular to the chord line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What happens to airflow parallel to the chord line?

A

It accelerates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What happens to airflow that is perpendicular to the chord line?

A

It reduces the amount of acceleration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Why would you want reduced acceleration on your wing?

A

Because it delays your critical mach number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is the purpose of span wise flow?

A

To delay your critical mach number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the benefit of having a delayed critical mach number?

A

You can fly at a high mach number before you start to create wave drag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is the disadvantage of having swept wings?

A

Reduces lift so you’ll need to have bigger wings (poor lift to drag ratio)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is an dihedral angle (positive dihedral)?

A

When the wings are pointing upwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is a anhedral angle (negative dihedral)?

A

When the wings are pointing downwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is the reason for dihedral angles?

A

It increases roll stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

When is a positive dihedral more commonly used?

A

On larger commercial aircraft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Why do military combat aircraft have small dihedral?

A

To increase manoeuvrability but reduces stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What types of aircraft use anhedral wings?

A

Fighter aircraft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Why are anhedral wings used?

A

To increase manoeuvrability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What type of pressure is at the front and back of the profile?

A

Static pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What type of pressure is on top and bottom of the profile?

A

Dynamic pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Where is static pressure highest?

A

At the point of stagnation where the air comes to a stop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What happens to the profile around the camber?

A

Max air velocity and minimum static pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What is aerodynamic force?

A

It is the resultant of all forces on a profile in an airflow acting on the centre of pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What are the two components to aerodynamic force?

A

Lift and drag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What is centre of pressure?

A

The point on which all pressures and forces act

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Where is the centre of pressure located?

A

Where the chord intersects with the resultant of aerodynamic forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What does aerodynamic forces of lift and drag depend on?

A
  • dynamic pressure
  • surface area of profile
  • shape of profile
  • angle of attack
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What is the calculation for theoretical lift and drag?

A

1/2xqxV2xA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

How do you calculate actual lift?

A

You cant you have to use a wind tunnel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

How is the coefficient of lift measured?

A

Measured lift
——————
theoretical lift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What is the lift equation when you have the coefficient of lift?

A

Coefficient of lift X dynamic pressure X surface area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

How is the coefficient of drag measured?

A

Measured drag
———————
theoretical drag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Why is a coefficient lift and drag used?

A

To account for the difference between theoretical figures and actual figures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

What is the drag equation when you have the coefficient of drag?

A

Coefficient of drag X dynamic pressure X surface area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What is alpha max?

A

The maximum angle of attack

71
Q

What happens after alpha max?

A

A stall occurs

72
Q

What is an advantage of having a high maximum lift coefficient?

A

It can fly slowly

73
Q

What will ice and frost do to the coefficient of lift and angle of attack?

A

It will be reduced

74
Q

What happens to the coefficient of drag when you increase the angle of attack?

A

It increases

75
Q

What does a stall produce?

A

A large increase in drag

76
Q

What is a polar diagram used for?

A

To figure out the best glide ratio

77
Q

What information does the polar diagram use?

A

Coefficient of lift and coefficient of drag

78
Q

Who invented wind tunnel tests?

A

Otto Lilienthal in the 19th century

79
Q

Name the variation of polar diagram?

A

Lift drag ratio diagram

80
Q

What happens to lift as climb increases?

A

It decreases therefore the pilot increases thrust

81
Q

What is drag parallel with?

A

Relative wind

82
Q

What is drag opposite to?

A

Thrust

83
Q

What are the different categories of drag?

A
  • induced drag
  • parasite drag
  • compressible drag
84
Q

What causes induced drag?

A

Lift

85
Q

How are wing tip vortices created?

A

The high pressure underneath ‘spills over’ onto the the top low pressure causing turbulence

86
Q

What is bound vortex?

A

The up-wash ad down-wash affect

87
Q

What creates the up-wash and down-wash on the wings?

A

Bound vortex and wing tip vortices

88
Q

What are the gutters inline with?

A

They are in line with the flow pattern of the airstream around the wing

89
Q

What are the gutters above the door designed for?

A

To reflect the up-wash and down-wash

90
Q

What directions are the gutters facing that reflect up-wash?

A

They’re sloped upwards

91
Q

What directions are the gutters facing that reflect down-wash?

A

They’re sloped downwards

92
Q

What affects the induced drag?

A
  • aspect ratio
  • wing tip design
  • aircraft speed
93
Q

How do you reduce wing tip vortices?

A

By using wing tip fences or winglets

94
Q

If an aircraft has a high angle of attack what is also high?

A

The lift coefficient

95
Q

What are the different types of parasite drag?

A
  • form
  • friction
  • Interference
96
Q

What causes form drag?

A

Distribution of pressure

97
Q

What causes friction drag?

A

Skin friction

98
Q

What is interference drag?

A

The difference between individual drag and total drag from the indivuals

99
Q

What causes compressible drag?

A

Shockwaves when the aircraft approaches the speed of sound

100
Q

What does form drag depend on?

A

The frontal area and the speed of airflow

101
Q

How is form drag reduced?

A

By streamlining

102
Q

What is form drag on the wing called?

A

Wing drag or profile drag

103
Q

What is the retarded air called?

A

The boundary layer

104
Q

How is a boundary layer created?

A

By having a rough surface layer causing airflow particles to stop

105
Q

What are the two types of boundary layer?

A
  • laminar boundary layer

- turbulent boundary layer

106
Q

Where is the laminar boundary layer located?

A

Immediately down stream of the leading edge until the point of maximum thickness

107
Q

In the laminar boundary layer the air particles don’t move from one layer to another, what’s this called?

A

Laminar flow

108
Q

Where is the turbulent boundary layer located?

A

Downstream of the laminar boundary layer

109
Q

What happens when air particles travel from one layer to another?

A

There is an energy exchange

110
Q

How much more drag does the turbulent boundary layer produce?

A

Three times more

111
Q

What boundary layer is the thickest?

A

The turbulent boundary layer

112
Q

The turbulent boundary layer produces higher kinetic energy, what does this reduce?

A

The tendency for flow separation

113
Q

How does flow separation occur?

A

When the air particles are unable to reach the high pressure because they stop moving

114
Q

How is flow separation prevented?

A

By a slot in the profile

115
Q

How does the slot in a profile work?

A

It allows high energy from the lower side to give stationary air energy

116
Q

How can Interference drag be reduced?

A

By fairings

117
Q

Where does compressible drag occur?

A

Transonic and supersonic

118
Q

What happens to the boundary layer as it passes through the shockwave?

A

It thickens

119
Q

What occurs when the boundary layer thickens?

A

Flow separation

120
Q

What makes up total drag?

A

Induced drag and parasite drag

121
Q

When is the induced drag high?

A

At low speeds (decreases as speed increases)

122
Q

When does parasite drag increase?

A

When speed increases

123
Q

When is total drag high?

A

When either induced or parasite drag is high

124
Q

What are the four types of wing shapes?

A
  • elliptical
  • rectangular
  • tapered
  • swept
125
Q

What is induced drag sometimes called?

A

Trailing vortex drag

126
Q

Where does stall begin on an elliptical wing?

A

All over

127
Q

Where does stall begin on a rectangular wing?

A

At the root

128
Q

Where does stall begin on a tapered and swept wing?

A

At the tip

129
Q

What is the reason for different stall characteristics?

A

The down-wash changes the angle of attack

130
Q

What does a high down-wash produce?

A

A low local angle of attack

131
Q

What does a low down-wash produce?

A

A high local angle of attack

132
Q

What does an elliptical wing constantly have?

A

Down-wash

133
Q

What does the constant down wash on the elliptical wing produce?

A

Constant flow separation

134
Q

Why does the rectangular wing have a large tip vortex?

A

Because it has a larger down-wash at the tip than the root

135
Q

What does the stall at the wing tip have dangerous implications on?

A

Lateral control and stability

136
Q

How do you make sure the root stalls first?

A

By geometrically or aerodynamically twisting the wing

137
Q

What is it called when you geometrically twist the wing?

A

Washing out

138
Q

What does it mean by geometrically twisted?

A

The camber is the same but the angle of incidence changes

139
Q

What does it mean by aerodynamically twisted?

A

The camber gradually gets smaller

140
Q

How are the chord lines layed out on an geometrically twisted wing?

A

Not in parallel

141
Q

How are the chord lines layed out on an aerodynamically twisted wing?

A

Are in parallel

142
Q

On a twisted wing, where does flow separation occur first?

A

At the root

143
Q

When increasing the angle of attack, what happens to the centre of pressure?

A

It moves towards the leading edge

144
Q

What does the total weight of the aircraft act on?

A

The centre of gravity

145
Q

What does the aircraft rotate round?

A

The centre of gravity

146
Q

What happens when the position of the centre of gravity is the same as the centre of lift?

A

Nothing the aircraft is in steady flight

147
Q

What happens when the position of the centre of gravity is behind the centre of lift?

A

The aircraft goes nose up

148
Q

What happens when the position of the centre of gravity is in front of the centre of lift?

A

The aircraft goes nose down

149
Q

Where does the total wing lift act on?

A

The centre of lift

150
Q

What is the mean aerodynamic chord (MAC)?

A

The chord line through the centre of lift

151
Q

How is the centre of lift on the wing described?

A

In percentages (0 from leading edge to 100 at the trailing edge

152
Q

What happens to the centre of lift when flow separation occurs next to the root of the wing?

A

It moves to the tip of the wing

153
Q

Will an aircraft recover from a root stall without pilot input?

A

Yes it will

154
Q

What happens to the centre of lift at a root stall?

A

It moves behind the centre of gravity

155
Q

What happens to the centre of lift at a tip stall?

A

It moves in front of the centre of gravity

156
Q

Is pilot input needed to recover from a wing tip stall?

A

Yes it is

157
Q

What is a stall strip?

A

A knife edge on the leading edge that prevents wing tip stalls occurring first

158
Q

What is the disadvantage of a stall strip?

A

It disturbs lift

159
Q

What are slats used for?

A

To prevent wing tip stall

160
Q

Where would you find stall strips?

A

On the leading edge of wing root on small aircraft

161
Q

Where would you find slats?

A

On the leading edge of the wing tips on larger aircraft

162
Q

How do slats work?

A

It alters the profile to allow the boundary layer to receive more energy

163
Q

What do slats prevent?

A

Flow separation at the wing tip

164
Q

What do wing fences do?

A

Reduce spanwise flow

165
Q

What are wing fences also known as?

A

Boundary layer fences

166
Q

What has the same affect as a saw tooth leading edge?

A

Wing fences

167
Q

What is a vortex generator?

A

A small low aspect ratio wing on top of the wing

168
Q

What do vortex generators do?

A

It produces lift by taking air from above the boundary layers and adding it to the boundary layer

169
Q

Why is the vortex large compared to the vortex generator?

A

Because of the aspect ratio

170
Q

What is the temperature at sea level?

A

288k

171
Q

What is the density at seal level?

A

1.225 kg/m3

172
Q

What is the pressure at sea level?

A

1013.25 hecto pascals

173
Q

what is the fineness ratio?

A

Length x thickness

M8 R (5 decks)

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