Brainscape's Knowledge GenomeTM

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


See full index

Aircraft Structures and Design 1Aero > Structures and Design Part 1 1Aero > Flashcards

Structures and Design Part 1 1Aero Flashcards

1
Q

is the intellectual engineering process of creating on paper (or on a computer screen)

A

Airplane Design

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

These are:
* Payload and type
* Range and/or loiter requirements
* Cruise speed and altitude
* Field length for take-off and landing
* Fuel reserves
* Climb requirements
* Maneuvering requirements
* Certification base (experimental, FAR 23, FAR 25, military)

A

Design Profile

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

How many design requirements are there?

A

12

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

These are what?
1. Range.
2. Take-off distance.
3. Stalling velocity.
4. Endurance [usually important for reconnaissance airplanes; an overall dominating factor for the new group of very high-altitude uninhabited air vehicles (UAVs) that are of great interest at present].
5. Maximum velocity.
6. Rate of climb.
7. For dogfighting combat aircraft, maximum tum rate and sometimes minimum tum radius.
8. Maximum load factor.
9. Service ceiling.
10. Cost.
11. Reliability and maintainability.
12. Maximum size (so that the airplane will fit inside standard hangars and/or be able to fit in a standard gate at airline terminals).

A

Design Requirements

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

What is the starting point in aircraft design?

A

Design Concept

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q
  • dynamic and fluid multidisciplinary design process
  • low level of detail
A

Conceptual Design

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  • Large number design alternatives
  • guide and evaluate design requirements of the overall aircraft contributors
A

Conceptual Design

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  • study of “global” or significant interactions
  • small, self- considerations group of contributors
A

Conceptual Design

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  • major configurations fixed
  • occasional reshapes of the overall design
A

Preliminary Design

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q
  • increasing level of detail and of understanding of the design
  • commencement of sub-system analysis and design by specialists
A

Preliminary Design

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q
  • validation of the aircraft concept (predictions of the conceptual design phase)
A

Preliminary Design

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

*full-scale development by large number of monodisciplinary designers and analysts
*ramified organisational structure

A

Detail Design

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

*High level of detail (analysis and design)
*High level of confidence required regular

A

Detail Design

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

*Regular checks of design goals
*field test result (esp. of components) become available

A

Detail Design

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

What is the seven intellectual pivot points for conceptual design?

A
  1. Requirements
  2. Weight of the airplane - first estimate
  3. Critical performance parameters
    -CL max
    -L/D
    -Wing Loading
    -Thrust to weight ratio T/W
  4. Configuration Layout - shape and size of the airplane on a drawing ( or computer screen)
  5. Better weight estimate
  6. Performace analysis
  7. Optimization - is it the best design?
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

These are what?
-CL max Maximum coefficient of lift
-L/D Lift to drag ratio
-Wing Loading W/S
-Thrust to weight ratio T/W

A

Critical Performace Parameters

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

shape and size of the airplane on a drawing ( or computer screen)

A

Configuration Layout

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

Any deformable solid body which is capable of carrying loads and transmitting these loads to other parts of the body

A

Structural System

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

Are one-dimensional structural members which are capable of carrying and transmitting bending, shearing, torsional, and axial loads or a combination of all four.

A

Bar elements

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

Bars which are capable of carrying only axial loads are referred to as axial rods or two-force members.

A

Bar elements

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

Structural systems constructed entirely out of axial rods are called

A

Trusses

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

frequently are used in many atmospheric, sea, and land based structures, since simple tension or compression members are usually the lightest for transmitting forces.

A

Trusses

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

Are two dimensional extensions of bar elements.

A

Plate elements

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

Plates made to carry only in-plane axial loads are called

A

membranes.

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

Those which are capable of carrying only in-plane shearing loads are referred to as

A

shear panels

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

frequently these are found in missile fins, aircraft wing, and tail surfaces.

A

shear panels

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

are curved plate elements which occupy a space. Fuselages, building domes, pressure vessels, etc., are typical examples of shells.

A

Shell elements

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

Fuselages, building domes, pressure vessels, etc., are typical examples of

A

shells

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

those loads which are produced by surface contact. Examples are dynamic and/ or static pressures.

A

Surface load

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

If the area of contact is very small, then the load is said to be concentrated; otherwise, it is called a

A

distributed load.

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

Loads which depend on body volume are called. Examples are inertial, magnetic, and gravitational forces.

A

Body loads

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

Generally, these loads are assumed to be distributed over the entire volume of the body

A

Body loads

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

are time dependent, whereas static loads are independent.

A

Dynamic loads

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

are created on a restrained structure by a uniform and/or nonuniform temperature change

A

Thermal loads

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

may be defined as a force whose vector representation lies in and parallel to the plane of the cut.

A

Bending moment

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

is a force whose vector representation is normal to that cut.

A

Torque

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

is a force which lies in and is parallel to the plane of the cut.

A

Shear load

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

is a force which acts normal to the plane of the cut

A

Axial loads

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

A structure is said to be (blank) if all its external reactions and the internal loads on its members can be obtained by utilizing only the static equations of equilibrium.

A

Determinate

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

A structure is said to be determinate if all its external reactions and the internal loads on its members can be obtained by utilizing only the static equations of equilibrium. Otherwise the structure is said to be

A

statically indeterminate (redundant structure)

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

lift, drag, and pitching-moment force distributions for the complete aircraft with the horizontal tail removed, through the range of angles of attack from the negative stalling angles to the positive stalling angle. Are the?

A

The first aerodynamic data required for the structural system analysis

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

loads used by civil agencies or loads used by military agencies are the maximum anticipated loads in the entire service life-span of the vehicle.

A

Limit loads/ Applied loads

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

commonly referred to as design loads, are the limit loads multiplied by a factor of safety (FS):

A

The ultimate loads

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

Factor Safety is equal to

A

ultimate load / limit load

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

is a factor by which basic loads on a vehicle are multiplied to obtain the limit loads

A

Limit load factor

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

is a factor by which basic vehicle loads are multiplied to obtain the ultimate loads; in other words, it is the product of the limit load factor and the factor of safety.

A

Ultimate load factor

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

is obtained in a pullout at the highest possible angle of attack on the wing.

A

Positive High Angle of Attack (PHAA) condition

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

The lift and drag forces are perpendicular and parallel respectively, to the relative wind, which is shown as horizontal.

A

Positive High Angle of Attack (PHAA) condition

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

the wing has the smallest possible angle of attack at which the lift corresponding to the limit-load factor may be developed.

A

Positive Low Angle of Attack (PLAA) condition

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

For a given lift on the wing, the angle of attack decreases as the indicated airspeed increases,

A

Positive Low Angle of Attack (PLAA) condition

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

condition corresponds to the maximum indicated airspeed at which the airplane will dive.

A

Positive Low Angle of Attack (PLAA) condition

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

This condition represents an upward acceleration at its design gliding speed Vg

A

Positive Low Angle of Attack (PLAA) condition

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

design gliding speed

A

Vg

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

occurs in intentional flight maneuvers in which the air loads on the wing are down or when the airplane strikes sudden downdrafts while in level flight

A

Negative High Angle of Attack (NHAA) condition

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

In this condition usually the wing is assumed to be at the negative stalling angle of attack for steady flow conditions.

A

Negative High Angle of Attack (NHAA) condition

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

occurs at the diving-speed limit of the airplane.

A

Negative Low Angle of Attack (NLAA) condition

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

This condition may occur in an intentional maneuver producing a negative load factor or in a negative gust condition.

A

Negative Low Angle of Attack (NLAA) condition

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

This condition allows for the effect of a sudden decrease in angle of attack while flying at the speed of Vg

A

Negative Low Angle of Attack (NLAA) condition

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

The (blank) load factors on an aircraft are greater when it is flying at the minimum flying weight than they are at the gross-weight condition.

A

gust load factors

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

A critical load-bearing structure on an aircraft

A

Primary Structure

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

If this structure is severely damaged, the aircraft cannot fly

A

Primary Structure

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

Structural elements mainly provide enhanced aerodynamics

A

Secondary Structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

a rigid framework made up of members such as beams, struts, and bars to resist deformation by applied loads.

A

Truss Type

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

Aircraft Structures where The skin carries all the load

A

Monocoque

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

Aircraft Structures where Unstiffened Shell. Must be relatively thick to resist bending, compressive, and torsional loads

A

Monocoque

66
Q

Aircraft Structures where Consist of skin and frames/formers/ bulkhead

A

Monocoque

67
Q

Construction with stiffening members that may also be required to diffuse concentrated loads into the cover

A

Semi-Monocoque

68
Q

More efficient type of construction that permits much thinner covering shell

A

Semi-Monocoque

69
Q

Reacts the applied torsion and shear forces transmits aerodynamic forces to the longitudinal and transverse supporting members

A

Skin

70
Q

Acts with longitudinal members in resisting the applied bending and axial loads

A

Skin

71
Q

Acts with the transverse members in reacting the hoop, or circumferential, load when the structure is pressurized

A

Skin

72
Q
  • Resist bending and axial loads
  • Form the wing box for stable torsion resistance
A

Spar

73
Q

Resist bending and axial loads along with the skin

A

Stiffener and Stringers

74
Q

Divide the skin into small panels and thereby increase its buckling and failing stresses

A

Stiffener and Stringers

75
Q

Act with the skin in resisting axial loads caused by pressurization

A

Stiffener and Stringers

76
Q

Main longitudinal member of a fuselage or nacelle.

A

Longeron

77
Q

Member taking a tensile load.

A

Tie Rod (Tension Rod)

78
Q

Member taking a compression load.

A

Strut

79
Q

Structure where loads are shared between skin and framework.

A

Stressed skin

80
Q

A partition within the structure. Usually lateral but can be longitudinal.

A

Bulkhead

81
Q

If it forms the boundary of pressurized structure it is called

A

pressure bulkhead

82
Q

A reinforcing member normally placed at right angles to the path of an anticipated crack which will reduce the rate of further propagation.

A

Crack stopper

83
Q

A flat sheet triangular in shape used to reinforce the corners of structure.

A

Gussets

84
Q

structural element frequently used to carry the fuselage bending loads through the portion of the lower fuselage which is cut up by the wheel wells.

A

Keelson/Keel beam

85
Q

Profile Drag + Induced Drag is equal to

A

Total Drag

86
Q

What formula is this 𝑪𝑫=𝑪𝑫𝒐+𝑪𝑫𝒊

A

Total Drag

87
Q

Drag induced while producing lift
This type of drag decreases as speed increases

A

Induced Drag

88
Q

Drag produced by shape and form of the aircraft

A

Profile / Form Drag

89
Q

This type of drag increases as speed increases
Part of this drag is interference drag and exceedance drag

A

Profile / Form Drag

90
Q

Drag is generated by the mixing of airflow streams between airframe components, such as the wing and the fuselage, or the landing gear strut and the fuselage.

A

Interference Drag

91
Q

Drag produced due to surface roughness. Could be reduce by installing flush fasteners or using flush repair or application of filleting sealants

A

Exceedance Drag

92
Q

Fuselage Shape Where:
- Efficient Structural Design
- Offers theoretically greater strength for shell structure
- Inefficient in availability of useful shape

A

Circular Cross Section

93
Q

Fuselage Shape Where:
- Permits the most economical use of the space
- Not Suitable for shell structures

A

Rectangular Cross Section

94
Q

Fuselage Shape Where:
- Best Compromise between circular and rectangular cross section

A

Oval/Elliptical Cross Section

95
Q

the primary function of the (blank) are:
1. Maintain the shape of the fuselage
2. To sustain concentrated loads imposed
3. Serve as attachments for equipment, flooring, and the like
4. Transmit the loads to adjacent structural members

A

transverse fuselage frames

96
Q
  1. Serve mainly to maintain the shape of the fuselage
  2. These are not subjected to stress unless distortion of the entire adjacent structure has taken place
A

Simple Frames

97
Q
  1. Serve to act as anchorage for medium weight equipment, control system and the like.
  2. Similar simple frames but must be reinforced locally to carry the load and reduce deflection to a minimum
A

Intermediate Frames

98
Q
  1. Additional brackets may have to be introduced and tied in with the longitudinal stingers as well as the frames
  2. These are not subjected to stress unless distortion of the entire adjacent structure has taken place
A

Intermediate Frames

99
Q
  1. To which large external loads are supplied through the landing gear, powerplant, or wing structure.
A

Main Frames

100
Q
  1. These are usually two in number, spaced a small distance apart and designed so as to take fittings to serve as carry through members
  2. Act as the main transverse load carrying member
A

Main Frames

101
Q

Since the fuselage is essentially a beam, the longitudinal stringers serve an important function in that they, along with the effective width of sheet covering, are the main bending elements of the structure.

A

Stringers

102
Q

are the main bending elements, they should be continuous and therefore pass through the transverse frame

A

stringers

103
Q

Since the openings have to be reinforced along the edges, it is desirable to have the top and bottom of all frames for such opening rest on

A

longitudinal stringers

104
Q

spacing is determined by the number required for the loads imposed.
Longitudinal members are spaced from 6 to 12 inches apart around the largest cross section.

A

stringer

105
Q

Since the cross section gradually decreases in size, the spacing is closer towards the tail post so that alternated members may be stopped at a forward frame.
It is desirable not to end all the longitudinal members at the same frame.

A

stringer

106
Q

is essentially a beam that is subjected to shear, bending, and torsion imposed upon it by aerodynamics and inertia loads.

A

Wings

107
Q

The center of gravity of the complete airplane is placed, usually at the maximum forward position of the center of pressure on the (blank) in order to get the desired stability

A

Mean Aerodynamic Chord

108
Q

is difficult to determine unless the pressure distribution is know. Moreover, the pressure distribution varies with angle of attack. It is customary therefore to use the mean geometric chord of the wing instead.

A

mean aerodynamic chord

109
Q

is determined for only 1/2 of the wing, either to the side of the fuselage, or up to the plane of symmetry for a parasol wing

A

The mean aerodynamic chord, or mean geometric chord

110
Q

A wing with taper is a trade-off between elliptical (least induced drag, difficult to manufacture) and a rectangular wing (more induced drag, easy to manufacture).

A

Taper Ratio

111
Q

More taper (smaller taper ratio) means weight is

A

less

112
Q

More taper (small tip chord) is more conducive to

A

tip stall

113
Q

Less taper means more fuel

A

volume

114
Q

Tapered wings cost more than

A

untapered wings

115
Q

For Aircraft operating at high subsonic speeds, the use of the sweepback in the planform of the wing is favored in order to increase the critical Mach number of the wing

A

Sweepback

116
Q

Advantages:
▪ Delays drag divergence effects
▪ Used for balance
▪ Used for stability (dihedral effect)
▪ Better ride through turbulence characteristics

A

Sweepback

117
Q

Disadvantages
Contributes to pitch up characteristics
▪ Performs less during take-off and landing
▪ Reduces subsonic lift
▪ Significant weight penalty
▪ Liable to tip stall

A

Sweepback

118
Q

Increase lateral stability. Angle varies around 3 to 8 degrees

A

Dihedral

119
Q

Decrease lateral stability/ Angle varies around 3 to 6 degrees
Also known as negative dihedral or drooped wing

A

Anhedral

120
Q

is weight of aircraft over wing area (W/S)

A

Wing loading

121
Q

Affects [a] take-off and landing field length, [b] cruise performance (L/D), [c] ride through turbulence, and [d] weight

A

Wing Loading

122
Q

High W/S mean Stall Speed is

A

High

123
Q

▪ For cruise at (L/D)max, a high wing loading is required
▪ For flight at high altitudes and at low speeds, a large wing is required.
▪ Of course a large wing means more weight

A

Wing Loading

124
Q

Low W/S means Stall Speed is

A

Low

125
Q

If Fieldlength ( Landing and Take-off) is Long, Wing Loading is

A

High

126
Q

If Fieldlength ( Landing and Take-off) is Short, Wing Loading is

A

Low

127
Q

L/D max is high when Wing Loading is

A

High

128
Q

L/D max is low when Wing Loading is

A

Low

129
Q

Good Ride qualities in turbulence when Wing loading is

A

High

130
Q

If weight is low then Wing loading is

A

High

131
Q

If weight is high then Wing loading is

A

low

132
Q

The higher the AR, the higher the span,

A

the heavier

133
Q

Also means high lift curve slope; good approach
attitude; bad ride through turbulence

A

High Aspect Ratio

134
Q

means reduced induced drag;
increased (L/D)max

A

Aspect Ratio

135
Q

If induced drag is low the AR is

A

High

136
Q

If induced drag is High the AR is

A

Low

137
Q

If lift-curve slope is high the AR is

A

High

138
Q

If pitch attitude is (approach) is low then AR is

A

High

139
Q

If pitch attitude is (approach) is high then AR is

A

Low

140
Q

Good Ride qualities in turbulence when Aspect Ratio is

A

Low

141
Q

Poor Ride qualities in turbulence when Aspect Ratio is

A

High

142
Q

If Wing weight is High then the Aspect ratio is

A

High

143
Q

If Wing weight is low then the Aspect ratio is

A

Low

144
Q

if Wing Span is large the Aspect Ratio is

A

High

145
Q

if Wing Span is small the Aspect Ratio is

A

Low

146
Q

Wingtip has less area, there is less vortex induced downwash,
which means a lot less

A

induced drag.

147
Q

Most important geometric consideration when selecting and airfoil

A

Thickness Ratio

148
Q

Higher thickness ratio, higher

A

profile drag / wave drag

149
Q

If Higher thickness ratio weight is

A

Low

150
Q

Higher thickness ratio (up to 12-14%), means C/L max is

A

Higher

151
Q

Higher thickness ratio, greater

A

fuel volume

152
Q

tip airfoil has negative incidence relative to root airfoil.

A

Wash-out

153
Q

opposite of wash-out

A

Wash-in

154
Q
  • delays tip stall
    ▪ May increase induced drag
    ▪ Less-loaded tip; less strength requirements; less
    weight
A

Wash-out

155
Q

will only be optimal relative to lift distribution for one value of coefficient of lift

A

Wing twist

156
Q

Negative Twist

A

Wash out

157
Q

Positive Twist

A

Wash in

158
Q

one type of airfoil used, incidence is
changing relative to root chord.

A

Geometric Twist

159
Q

Incidence is proportional to distance from root airfoil.

A

Linear Twist

160
Q

difference in the zero-lift angles of the
root and tip airfoil. Same as geometric twist if one type of airfoil
is used

A

Aerodynamic Twist

161
Q

It is possible for a wing without geometric twist to have an (blank) This can happen, for example, when the
root and the tip are using different airfoil.

A

Aerodynamic Twist

Aircraft Structures and Design 1Aero (10 decks)

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