11.1 Theory Of Flight Flashcards
1
Q
Which Axis runs from wingtip to wingtip?
A. Longitudinal axis
B. Lateral Axis
C. Vertical Axis
A
B. Lateral Axis
2
Q
What type of motion occurs around the lateral axis?
A. Roll
B. Yaw
C. Pitch
A
C. Pitch
3
Q
Which control surface manages pitch motion?
A. Rudder
B. Elevator
C. Aileron
A
B. Elevator
4
Q
Which axis runs from the nose to the tail of the aircraft?
A. Lateral Axis
B. Vertical Axis
C. Longitudinal Axis
A
C. Longitudinal Axis
5
Q
What motion is controlled around the longitudinal axis?
A. Roll
B. Pitch
C. Yaw
A
A. Roll
6
Q
Which control surface is responsible for controlling roll?
A. Elevator
B. Aileron
C. Rudder
A
B. Aileron
7
Q
What is the name of the motion around the vertical axis?
A. Yaw
B. Pitch
C. Roll
A
A. Yaw
8
Q
Which axis runs vertically through the centre of gravity?
A. Lateral Axis
B. Longitudinal Axis
C. Vertical Axis
A
C. Vertical Axis
9
Q
What control surface is used to control yaw?
A. Rudder
B. Elevator
C. Aileron
A
A. Rudder
10
Q
How does the elevator control pitch?
A. By changing the aircraft’s yaw rate
B. By varying the aircraft’s angle of attack
C. By increasing engine thrust
A
B. By varying the aircraft’s angle of attack
11
Q
What are the three primary flight controls?
A. Ailerons, Elevators, Rudder
B. Canards, Stabilisers, Elevators
C. Ailerons, Spoilers, Flaps
A
A. Ailerons, Elevators, Rudder
12
Q
Where are ailerons located on an aircraft?
A. On the vertical stabiliser
B. On the outboard trailing edge of each wing
C. On the fuselage near the cockpit
A
B. On the outboard trailing edge of each wing
13
Q
What motion do ailerons primarily control?
A. Yaw
B. Pitch
C. Roll
A
C. Roll
14
Q
What happens when the control stick is moved to the right?
A. Left aileron goes up, right goes down
B. Right aileron goes up, left goes down
C. Both ailerons move down
A
B. Right aileron goes up, left goes down
15
Q
How does an upward-deflected aileron affect lift?
A. Increases lift
B. Reduces lift
C. Has no effect on lift
A
B. Reduces lift
16
Q
What is the aerodynamic result of one aileron going up and the other down?
A. The aircraft pitches up
B. The aircraft rolls
C. The aircraft yaws
A
B. The aircraft rolls
17
Q
Why do high-speed aircraft often use inboard and outboard ailerons?
A. To balance fuel consumption
B. To reduce drag
C. To maintain roll control at different speeds
A
C. To maintain roll control at different speeds
18
Q
What happens to the outboard ailerons at high speeds?
A. They are locked out
B. They deflect further
C. They increase lift on both wings
A
A. They are locked out
19
Q
What is the primary role of roll spoilers?
A. To increase pitch stability
B. To increase drag only
C. To assist ailerons by reducing lift on one wing
A
C. To assist ailerons by reducing lift on one wing
20
Q
How do roll spoilers reduce the effects of adverse yaw?
A. By increasing engine power
B. By reducing lift-induced drag on the wing with the upgoing aileron
C. By deflecting both ailerons upward
A
B. By reducing lift-induced drag on the wing with the upgoing aileron
21
Q
Why is less aileron deflection needed at high speeds with spoilers?
A. Because lift is no longer needed
B. Because spoilers produce extra thrust
C. Because spoilers assist roll control, reducing the need for large aileron input
A
C. Because spoilers assist roll control, reducing the need for large aileron input
22
Q
What axis do elevators control movement around?
A. Longitudinal axis
B. Lateral axis
C. Vertical axis
A
B. Lateral axis
23
Q
What is the effect of pulling back on the control column?
A. Nose-down pitch
B. Yaw to the left
C. Nose-up pitch
A
C. Nose-up pitch
24
Q
Where are elevators typically located?
A. On the main wing
B. On the trailing edge of the horizontal stabiliser
C. On the vertical stabiliser
A
B. On the trailing edge of the horizontal stabiliser
25
What makes a stabilator different from a conventional elevator?
A. It only controls yaw
B. It combines elevator and stabiliser into a single moving surface
C. It is only found on helicopters
B. It combines elevator and stabiliser into a single moving surface
26
Why are stabilators commonly used on high-speed military aircraft?
A. To reduce noise during flight
B. To enhance pitch control at high speeds
C. To increase pilot comfort
B. To enhance pitch control at high speeds
27
What aerodynamic issue do stabilators help to overcome in transonic flight?
A. Hydraulic failure
B. Turbulent air near wing tips
C. Shockwaves near elevator hinge line
C. Shockwaves near elevator hinge line
28
What is the function of a variable incidence stabiliser?
A. Real-time yaw trimming
B. Limited-range pitch trimming
C. Automatic pitch control
B. Limited-range pitch trimming
29
How is the angle of the variable incidence stabiliser usually adjusted?
A. With rudder pedals
B. Using trim wheels or autopilot input
C. Control dial next to left seat
B. Using trim wheels or autopilot input
30
Where are the canards positioned on an aircraft?
A. Behind the main wings
B. Before the stabiliser
C. In front of the main wings
C. In front of the main wings
31
What is one primary advantage of a canard configuration?
A. Reduces fuel burn
B. Helps prevent aerodynamic stalls
C. Increases drag during descent
B. Helps prevent aerodynamic stalls
32
What is the effect of canards stalling before the main wings?
A. Aircraft continues climbing
B. A nose-down moment is created to recover from stall
C. Aircraft enters a Dutch roll
B. A nose-down moment is created to recover from stall
33
In addition to pitch control, canards can also contribute to:
A. Improved fuel efficiency
B. Lift and flight trim
C. Assisting ailerons to roll the aircraft
B. Lift and flight trim
34
What is the rudder primarily used to control?
A. Pitch
B. Yaw
C. Roll
B. Yaw
35
Where is the rudder located on an aircraft
A. On the horizontal stabiliser
B. Hinged to the outboard trailing edge of the wing
C. Hinged to the rear of the vertical stabiliser
C. Hinged to the rear of the vertical stabiliser
36
What happens when the left rudder pedal is pushed?
A. Nose yaws to the right
B. Nose yaws to the left
C. Aircraft rolls left
B. Nose yaws to the left
37
Why are rudder limiters used on some aircraft?
A. To improve rudder deflection at low speed
B. To prevent rudder overuse at high speeds
C. To improve fuel efficiency
B. To prevent rudder overuse at high speeds
38
What component controls the rudder travel limiter on the Airbus A300?
A. Rudder Deflection Actuator
B. Feel and Limitation Computers (FLC)
C. Hydraulic Power Unit
B. Feel and Limitation Computers (FLC)
39
What does a rudder limiter NOT do?
A. Restrict rudder pedal movement
B. Limit rudder deflection
C. Prevent excessive structural load
A. Restrict rudder pedal movement
40
What is the relationship between yaw and roll?
A. They are completely independent
B. Yaw induces a roll and roll induces yaw
C. Yaw counteracts roll
B. Yaw induces a roll and roll induces yaw
41
What causes adverse yaw in light aircraft?
A. Uneven fuel distribution
B. Drag imbalance from aileron deflection
C. Low rudder sensitivity
B. Drag imbalance from aileron deflection
42
What is used to counteract adverse yaw?
A. Elevator trim
B. Leading edge slats
C. Frise or differential ailerons
C. Frise or differential ailerons
43
What do frise ailerons do to balance drag?
A. Adjust flap extension
B. Protrude into airflow to add profile drag
C. Flatten the wing camber
B. Protrude into the airflow to add profile drag
44
What do differential ailerons do to reduce adverse yaw?
A. Reduce wing twist
B. Deflection both ailerons equally
C. Deflect the up-going aileron more than the down-going one
C. Deflect the up-going aileron more than the down-going one
45
What happens when rudder is applied on an aircraft with a high vertical stabiliser?
A. Aircraft yaws more efficiently
B. A rolling moment occurs in the opposite direction
C. The aircraft pitches up
A rolling moment occurs in the opposite direction
46
What system helps to counter adverse roll due to rudder input?
A. Aileron booster
B. Aileron-rudder interconnect system
C. Pitch trim adjuster
B. Aileron-rudder interconnect system
47
What is Dutch roll?
A. A type of spin manoeuvre
B. Oscillating yaw and roll motion in swept-wing aircraft
C. A failure of the elevator system
B. Oscillating yaw and roll motion in swept-wing aircraft
48
How is Dutch roll dampened in modern aircraft?
A. Manual pilot input
B. Rudder pressure sensors
C. Yaw damping system
C. Yaw damping system
49
On which type of aircraft are elevens typically found?
A. Biplanes
B. Delta-wing aircraft
C. Helicopters
B. Delta-wing aircraft
50
Why do delta-wing aircraft use elevons?
A. They don’t have rudders
B. They don’t have a vertical stabiliser
C. They don’t have a horizontal stabiliser
C. They don’t have a horizontal stabiliser
51
Where are elevons located on a delta-wing aircraft
A. Leading edge of the wing
B. Trailing edge of the wing
C. Fuselage sides
B. Trailing edge of the wing
52
What happens when a pitch input is made on an aircraft with elevons?
A. Elevons move in opposite directions
B. Elevons deflect collectively
C. Only one elevon moves
B. Elevons deflect collectively
53
What happens when a roll input is made on an aircraft with elevons
A. Elevons move together in the same direction
B. Elevons move in opposite directions
C. Elevons are locked in place
B. Elevons move in opposite directions
54
How do elevons behave when both pitch and roll inputs are given simultaneously?
A. Only roll input is prioritised
B. Only pitch input is prioritised
C. They move differentially in the same direction
C. They move differentially in the same direction
55
What is a ruddervator?
A. A rudder used only during takeoff
B. A combined control surface for yaw and pitch
C. A vertical stabiliser with elevator functions
B. A combined control surface for yaw and pitch
56
On what type of aircraft are ruddervators typically found?
A. Swept wing aircraft
B. V-tailed aircraft
C. Delta-wing aircraft
B. V-tailed aircraft
57
What stabilisers are missing from V-tailed aircraft?
A. Vertical and horizontal stabilisers
B. Diagonal stabilisers
C. Wingtip stabilisers
A. Vertical and horizontal stabilisers
58
What do the angled stabilisers on a V-tail aircraft replace?
A. The ailerons
B. The rudder and the elevator
C. The wings
B. The rudder and elevator
59
How do ruddervators move to create yaw to the left on a V-tailed aircraft?
A. Both ruddervators move downward
B. Left ruddervator down and left, right ruddervator up and left
C. Both ruddervators move upward and inward
B. Left ruddervator down and left, right ruddervator up and left
60
Which of the following creates pitch nose-up using ruddervators?
A. Pulling the stick back
B. Pushing rudder pedals
C. Moving the stick to the left
A. Pulling the stick back
61
What kind of control system do ruddervators require?
A. Manual-only system
B. Simplified control linkage
C. A more complex system that actuates both surfaces in unison
C. A more complex system that actuates both surfaces in unison
62
Which control input causes pitch nose-down in a V-tailed aircraft?
A. Left rudder pedal
B. Stick pushed forward
C. Stick moved left
B. Stick pushed forward
63
What is the primary purpose of high-lift devices on an aircraft?
A. Reduce drag at cruise
B. Increase thrust during takeoff
C. Increase the amount of lift produced by the wing
C. Increase the amount of lift produced by the wing
64
Which of the following are classified as high-lift devices?
A. Elevons and ruddervators
B. Slots, slats, and flaps
C. Ailerons and rudders
B. Slots, slats, and flaps
65
What is a key difference between a slat and a slot?
A. Slats are fixed; slots are movable
B. Slots are movable; slats are fixed
C. Slats are movable, while slots are fixed
C. Slats are movable, while slots are fixed
66
What do slots allow high-pressure air to do?
A. Escape through the wingtip
B. Flow under the fuselage
C. Flow to the upper wing surface to re-energise the boundary layer
C. Flow to the upper wing surface to re-energise the boundary layer
67
How do slots affect stall behaviour?
A. They eliminate the need for stall recovery
B. They increase the stall angle, delaying stall
C. They lower the stall angle to reduce lift
B. They increase the stall angle, delaying stall
68
Why are slots often located ahead of ailerons?
A. To reduce drag
B. To keep aileron effectiveness during a stall
C. To decrease camber
B. To keep aileron effectiveness during a stall
69
What aerodynamic effect do slats have when deployed?
A. Reduce wing surface area
B. Increase wing camber and delay stall
C. Redirect airflow away from the fuselage
B. Increase wing camber and delay stall
70
How are slats typically controlled during flight?
A. Automatically with throttle
B. Independently or with flaps via cockpit controls
C. Only during engine startup
B. Independently or with flaps via cockpit controls
71
Do slots directly increase lift on their own?
A. Yes, they generate extra lift by themselves
B. No, but they delay stall allowing greater lift at higher angles of attack
C. Yes, especially at high speeds
B. No, but they delay stall allowing greater lift at higher angles of attack
72
What is the main purpose of flaps on an aircraft?
A. Increase thrust at takeoff
B. Increase lift during low-speed phases like takeoff and landing
C. Reduce fuel consumption
B. Increase lift during low-speed phases like takeoff and landing
73
What aerodynamic effect do flaps have when deployed?
A. Increase lift and drag
B. Decrease camber
C. Reduce surface area
A. Increase lift and drag
74
What happens to the aircraft’s pitch when flaps are extended?
A. Nose pitches up
B. Nose pitches down
C. There is no pitch change
B. Nose pitches down
75
How much can a plain flap increase lift by?
A. 30–35%
B. 50–55%
C. 80–85%
B. 50–55%
76
What is a drawback of the plain flap design?
A. Causes high drag and a nose-up moment
B. Causes high drag and a nose-down pitch moment
C. Reduces camber
B. Causes high drag and a nose-down pitch moment
77
What distinguishes a split flap from a plain flap?
A. It changes the upper surface of the wing
B. It increases surface area significantly
C. It modifies only the lower wing surface and causes more drag
C. It modifies only the lower wing surface and causes more drag
78
How much lift increase can a split flap provide?
A. 45–50%
B. 60–65%
C. 75–80%
B. 60–65%
79
What is the advantage of slotted flaps?
A. Increase lift by reducing wing area
B. Allow airflow to re-energise the boundary layer and delay separation
C. Reduce wing drag at all speeds
B. Allow airflow to re-energise the boundary layer and delay separation
80
How much lift increase do slotted flaps provide?
A. 65–70%
B. 50–55%
C. 85–90%
A. 65–70%
81
What do multiple (double/triple) slotted flaps offer to large aircraft?
A. Less lift and more weight
B. Maximum drag and boundary layer control without destroying lift
C. Higher pitch control
B. Maximum drag and boundary layer control without destroying lift
82
What distinguishes Fowler flaps from other flap types?
A. They deploy upwards and increase angle of attack
B. They extend backward first, then downward to increase wing chord
C. They remain fixed during flight
B. They extend backward first, then downward to increase wing chord
83
How much lift can a Fowler flap increase by?
A. Up to 70%
B. Up to 80%
C. Up to 95%
C. Up to 95%
84
What is the main benefit of slotted Fowler flaps?
A. Reduces lift and increases drag
B. Re-energises airflow and increases lift with minimal drag penalty
C. Only improves stall recovery
B. Re-energises airflow and increases lift with minimal drag penalty
85
What is the purpose of leading edge flaps on heavy aircraft?
A. Reduce drag at cruise speeds
B. Increase camber and lift when used with trailing edge flaps
C. Provide roll control during high-speed turns
B. Increase camber and lift when used with trailing edge flaps
86
When are leading edge flaps typically deployed?
A. Only during engine start
B. Manually by the pilot only
C. Automatically when trailing edge flaps are selected
C. Automatically when trailing edge flaps are selected
87
What happens when leading edge flaps are stowed?
A. They extend downward
B. They retract into the leading edge of the wing
C. They rotate upward into the fuselage
B. They retract into the leading edge of the wing
88
What is a leading edge droop designed to do?
A. Reduce drag at high speeds
B. Improve airflow over the wing at high angles of attack
C. Increase control responsiveness
B. Improve airflow over the wing at high angles of attack
89
How does a droop differ from a slat?
A. A droop uses a fixed panel while a slat rotates
B. A droop is a rotating section of the entire leading edge
C. A slat is used for pitch control, not lift
B. A droop is a rotating section of the entire leading edge
90
Where are droops mounted on an aircraft like the Airbus A380?
A. Under the wing near the landing gear
B. On the trailing edge
C. On the thickest part of the leading edge between fuselage and inboard engine
C. On the thickest part of the leading edge between fuselage and inboard engine
91
What is unique about the deployment of Krueger flaps?
A. They rotate out from the upper wing surface
B. They deploy from beneath the wing and hinge forward
C. They replace the wing tip devices
B. They deploy from beneath the wing and hinge forward
92
What aerodynamic effect do Krueger flaps have when deployed?
A. Nose-down pitching
B. Nose-up pitching
C. No pitch change
B. Nose-up pitching
93
How do Krueger flaps improve low-speed handling?
A. By sharpening the wing leading edge
B. By creating a more blunt leading edge
C. By decreasing wing camber
B. By creating a more blunt leading edge
94
What do flaperons combine the functions of?
A. Elevator and spoiler
B. Rudder and elevator
C. Aileron and flap
C. Aileron and flap
95
How do flaperons behave during takeoff and landing?
A. Only act as ailerons
B. They droop like flaps but still provide roll control
C. Lock into position
B. They droop like flaps but still provide roll control
96
How does the pilot control flaperons?
A. With a combined single control
B. By toggling between aileron and flap mode
C. With separate controls that are mixed mechanically
C. With separate controls that are mixed mechanically
97
Why are flaperons often mounted away from the wing?
A. To reduce drag at cruise
B. To improve fuel efficiency
C. To maintain airflow at high angles of attack
C. To maintain airflow at high angles of attack
98
What is the primary function of drag-inducing devices on an aircraft?
A. Increase engine thrust
B. Improve fuel economy
C. Increase drag to slow the aircraft or dump lift
C. Increase drag to slow the aircraft or dump lift
99
What are the two main drag-inducing devices on modern aircraft?
A. Ailerons and elevators
B. Spoilers and speed brakes
C. Rudder and flaperons
B. Spoilers and speed brakes
100
How do spoilers differ from air brakes?
A. Spoilers reduce lift as well as increase drag, while air brakes increase drag only
B. Air brakes are smaller
C. Spoilers are always located on the fuselage
A. Spoilers reduce lift as well as increase drag, while air brakes increase drag only
101
Where are spoilers typically located?
A. On the underside of the wing
B. On the upper surface of the wing
C. Inside the landing gear
B. On the upper surface of the wing
102
What happens when spoilers are deployed in flight?
A. They reduce engine power
B. They enhance lift
C. They interrupt airflow and dump lift
C. They interrupt airflow and dump lift
103
What are the three main functions of spoilers depending on aircraft type?
A. Stall prevention, climb assist, yaw control
B. Flight spoilers (speed brakes), ground spoilers (lift dumpers), and roll spoilers
C. Landing gear extension, flap control, engine cooling
B. Flight spoilers (speed brakes), ground spoilers (lift dumpers), and roll spoilers
104
What is the function of flight spoilers (speed brakes)?
A. Provide engine backup
B. Symmetrically extend to increase drag for descent control
C. Reduce wing surface area
B. Symmetrically extend to increase drag for descent control
105
What happens when flight spoilers are in the "armed" position?
A. They automatically extend in flight
B. They are stowed and only deploy automatically on the ground
C. They retract fully and disable roll control
B. They are stowed and only deploy automatically on the ground
106
When do ground spoilers (lift dumpers) activate?
A. During take-off roll
B. During flight to reduce lift
C. On landing roll or rejected take-off to maximise brake efficiency
C. On landing roll or rejected take-off to maximise brake efficiency
107
What is the purpose of ground spoilers during landing?
A. Increase lift to maintain altitude
B. Maximise brake effectiveness by dumping lift
C. Assist with engine power reduction
B. Maximise brake effectiveness by dumping lift
108
What are roll spoilers also known as?
A. Stabilators
B. Spoilerons
C. Flaperons
B. Spoilerons
109
What benefit do roll spoilers offer over ailerons during high-speed flight?
A. They increase fuel efficiency
B. They reduce adverse yaw and avoid wing twist
C. They enhance rudder authority
B. They reduce adverse yaw and avoid wing twist
110
What aerodynamic issue do roll spoilers help avoid that ailerons can cause?
A. Stall
B. Adverse yaw
C. Pitch oscillation
B. Adverse yaw
111
Where are speed brakes often mounted?
A. On the wingtip only
B. On the fuselage or tail cone
C. On the horizontal stabiliser
B. On the fuselage or tail cone
112
How are speed brakes different from spoilers in design and use?
A. Speed brakes are designed only to reduce lift
B. Speed brakes are often fuselage-mounted and only increase drag
C. Spoilers are used only after landing
B. Speed brakes are often fuselage-mounted and only increase drag
113
What causes the boundary layer on a swept-wing aircraft to thicken towards the wingtip?
A. Increased wing flexibility
B. Spanwise flow of air
C. Wingtip vortex
B. Spanwise flow of air
114
What is a potential problem caused by spanwise flow on swept-wing aircraft?
A. Increased fuel consumption
B. Wingtip stalling first, with little warning to the pilot
C. Excessive drag
B. Wingtip stalling first, with little warning to the pilot
115
What could happen if both wingtips stall simultaneously on a swept-wing aircraft?
A. The Centre of Pressure (CP) moves rearward
B. The Centre of Pressure (CP) moves forward, causing a nose-up pitch moment
C. The aircraft achieves a more stable flight
B. The Centre of Pressure (CP) moves forward, causing a nose-up pitch moment
116
What is one design solution to prevent wingtip stall on swept-wing aircraft?
A. Increase wing flexibility
B. Limit the spanwise airflow or re-energise the boundary layer
C. Add additional flaps
B. Limit the spanwise airflow or re-energise the boundary layer
117
What is the function of a wing fence on a swept-wing aircraft?
A. Increase drag to slow the aircraft
B. Redirect spanwise airflow to delay boundary layer separation and wingtip stall
C. Increase the wing's lift-to-drag ratio
B. Redirect spanwise airflow to delay boundary layer separation and wingtip stall
118
What is another name for a wing fence?
A. Winglet
B. Stall fence or boundary layer fence
C. Leading edge extension
B. Stall fence or boundary layer fence
119
Where are wing fences typically installed on the wing?
A. On the trailing edge
B. At the leading edge to limit boundary layer outflow
C. Near the ailerons
B. At the leading edge to limit boundary layer outflow
120
What is the primary purpose of a saw tooth leading edge (also known as a "dog-tooth") on swept-wing aircraft?
A. To increase the wing’s surface area
B. To reduce wingtip stall by redirecting spanwise airflow
C. To enhance aileron effectiveness
B. To reduce wingtip stall by redirecting spanwise airflow
121
How does a saw tooth leading edge help with boundary layer control?
A. By increasing the wing's camber
B. By creating a vortex that limits boundary layer outflow and delays stall
C. By reducing wing drag at high speeds
B. By creating a vortex that limits boundary layer outflow and delays stall
122
What is the drawback of using vortices created by saw tooth leading edges?
A. Increased stall speed
B. Increased drag
C. Decreased wing flexibility
B. Increased drag
123
What advantage do the vortices created by a saw tooth leading edge offer?
A. They improve engine efficiency
B. They help reinvigorate the airflow, increasing momentum, and delaying stall
C. They improve aerodynamic stability at all speeds
B. They help reinvigorate the airflow, increasing momentum, and delaying stall
124
In what way does the saw tooth leading edge redirect the spanwise flow on a swept wing?
A. By creating a vortex that stabilizes the airflow towards the fuselage
B. By redirecting airflow towards the ailerons
C. By limiting stagnation towards the wingtip and roll control surfaces
C. By limiting stagnation towards the wingtip and roll control surfaces
125
What is the primary function of a vortex generator on an aircraft wing?
A. To increase the surface area of the wing
B. To re-energise a slow-moving boundary layer by creating vortices
C. To reduce drag on the wing
B. To re-energise a slow-moving boundary layer by creating vortices
126
How does a vortex generator help in re-energising the boundary layer?
A. By creating a vortex that mixes high-energy air from outside the boundary layer with low-energy air
B. By increasing the wing’s camber to produce more lift
C. By deflecting the airflow downward to create more drag
A. By creating a vortex that mixes high-energy air from outside the boundary layer with low-energy air
127
How are vortex generators typically installed on the wing?
A. They are positioned at the trailing edge only
B. They are installed in opposing pairs to mix the vortices
C. They are mounted on the wingtip
B. They are installed in opposing pairs to mix the vortices
128
What is the purpose of a stall wedge (or stall strip) on an aircraft wing?
A. To prevent the wing root from stalling first
B. To encourage the root to stall first, ensuring a progressive stall pattern
C. To improve the efficiency of the wing flaps
B. To encourage the root to stall first, ensuring a progressive stall pattern
129
Where is a stall wedge typically placed on the wing?
A. On the trailing edge of the wing
B. On the inboard section of the wing, usually at the wing root
C. Near the ailerons
B. On the inboard section of the wing, usually at the wing root
130
How does a stall wedge help prevent an uncontrollable stall?
A. By creating turbulence that delays airflow separation
B. By initiating flow separation at the wing root, ensuring a progressive outward stall
C. By increasing the lift generated at high angles of attack
B. By initiating flow separation at the wing root, ensuring a progressive outward stall
131
What is the main advantage of a stall wedge during flight?
A. It reduces drag
B. It provides maximum aileron control throughout the stall
C. It enhances the aircraft’s speed
B. It provides maximum aileron control throughout the stall
132
What is the role of turbulence generated by a stall wedge at the wing root?
A. To prevent stall at any part of the wing
B. To buffet the tail and give the pilot a physical warning of an impending stall
C. To reduce the aerodynamic drag on the wing
B. To buffet the tail and give the pilot a physical warning of an impending stall
133
Which of the following is a type of leading-edge device discussed in the text?
A. Vortex generators
B. Stall wedges
C. Slats and slots
C. Slats and slots
134
How do leading-edge devices such as slots and slats re-energise the airflow?
A. By deflecting the airflow upwards to increase lift
B. By featuring a convergent duct that accelerates the airflow from beneath the wing to the upper surface
C. By increasing the surface area of the wing
B. By featuring a convergent duct that accelerates the airflow from beneath the wing to the upper surface
135
What happens when leading-edge devices such as slats and slots are deployed?
A. They create high-pressure areas to slow the airflow
B. They accelerate airflow from beneath the wing to reinvigorate the upper surface airflow
C. They increase drag without improving lift
B. They accelerate airflow from beneath the wing to reinvigorate the upper surface airflow
136
What material is commonly used to make stall wedges (or strips)?
A. Steel
B. Aluminium
C. Plastic
B. Aluminium
137
What is the main function of a trim tab on an aircraft?
A. To adjust the aerodynamic forces on the control surfaces so that the aircraft maintains a set attitude without control input
B. To increase the lift on the wings during takeoff
C. To reduce drag on the aircraft during high-speed flight
A. To adjust the aerodynamic forces on the control surfaces so that the aircraft maintains a set attitude without control input
138
Where are trim tabs typically located on an aircraft?
A. On the fuselage
B. On the trailing edge of a primary flight control surface
C. On the wings near the engine
B. On the trailing edge of a primary flight control surface
139
What is the difference between fixed and adjustable trim tabs?
A. Fixed trim tabs can only be adjusted in flight, while adjustable trim tabs can only be set on the ground
B. Fixed trim tabs are adjusted only on the ground, while adjustable trim tabs can be moved by the pilot during flight
C. Fixed trim tabs are found on the wings, and adjustable trim tabs are found on the tail
B. Fixed trim tabs are adjusted only on the ground, while adjustable trim tabs can be moved by the pilot during flight
140
How does a trim tab assist in maintaining the desired position of the control surface?
A. By deflecting in the same direction as the control surface to assist movement
B. By deflecting in the opposite direction to the control surface, creating a force to maintain the position
C. By reducing drag on the control surface to make it easier to move
B. By deflecting in the opposite direction to the control surface, creating a force to maintain the position
141
What can happen if excessive trim is required on a control surface?
A. It can lead to a loss of control authority
B. It could limit the range of movement of the control surface
C. It increases the efficiency of the control surface
B. It could limit the range of movement of the control surface
142
What is the role of a balance tab on an aircraft's control surface?
A. To assist in reducing the control surface's sensitivity
B. To create a force that assists in deflecting the control surface, reducing the force required to move it
C. To increase the control surface's efficiency by changing the wing's camber
B. To create a force that assists in deflecting the control surface, reducing the force required to move it
143
How does a balance tab work when the control surface is deflected?
A. It moves in the same direction as the control surface
B. It moves in the opposite direction to the control surface, reducing the force required to deflect it
C. It changes the angle of attack of the wing
B. It moves in the opposite direction to the control surface, reducing the force required to deflect it
144
What is a disadvantage of using a balance tab on a control surface?
A. It increases the control surface's sensitivity
B. It reduces the efficiency of the control surface
C. It prevents the control surface from returning to neutral
B. It reduces the efficiency of the control surface
145
How does an anti-balance tab differ from a balance tab?
A. The anti-balance tab moves in the opposite direction to the control surface, increasing resistance
B. The anti-balance tab moves in the same direction as the control surface, providing resistance to the movement
C. The anti-balance tab is located on the wing
B. The anti-balance tab moves in the same direction as the control surface, providing resistance to the movement
146
What is the purpose of using an anti-balance tab?
A. To reduce the force needed to move the control surface
B. To provide resistance to control surface movement, giving the pilot more ‘feel’ and improving control effectiveness
C. To increase the efficiency of the control surface at high speeds
B. To provide resistance to control surface movement, giving the pilot more ‘feel’ and improving control effectiveness
147
What happens when an anti-balance tab is deflected?
A. It assists in deflecting the control surface more easily
B. It moves in the same direction as the control surface, making the surface harder to deflect
C. It reduces drag on the control surface
B. It moves in the same direction as the control surface, making the surface harder to deflect
148
What is a disadvantage of the anti-balance tab?
A. It makes the control surface more efficient
B. It requires more effort to deflect the control surface
C. It increases the sensitivity of the control surface
B. It requires more effort to deflect the control surface
149
What is the primary purpose of a servo tab on a control surface?
A. To reduce the aerodynamic forces on the control surface
B. To allow the pilot to operate the control surface directly
C. To allow the pilot to control the tab, which then assists in moving the control surface
C. To allow the pilot to control the tab, which then assists in moving the control surface
150
How does a spring tab function on a control surface?
A. It is always active, regardless of airspeed
B. It only moves when the control surface loading exceeds a certain threshold
C. It assists the pilot in moving the control surface by reducing the required force
B. It only moves when the control surface loading exceeds a certain threshold
151
What is the relationship between the control surface loading and the spring tab's action?
A. The spring tab is inactive when the control surface loading is high
B. The spring tab assists movement when the loading on the control surface is low
C. The spring tab assists when the control surface loading is high, and the pilot's force overcomes the spring tension
C. The spring tab assists when the control surface loading is high, and the pilot's force overcomes the spring tension
152
What problem can arise if the centre of gravity (CG) is too far aft of the hinge line on a control surface?
A. It causes the control surface to be overly sensitive
B. It can lead to oscillations known as flutter
C. It increases the required force to move the control surface
B. It can lead to oscillations known as flutter
153
How is torsional aileron flutter prevented?
A. By mass-balancing the aileron so the CG is ahead of the hinge line
B. By increasing the flexibility of the wing
C. By making the control surfaces irreversible
A. By mass-balancing the aileron so the CG is ahead of the hinge line
154
What is flexural aileron flutter caused by?
A. The increased aerodynamic force on the control surface
B. The aileron lagging behind the movement of the wing during flexing
C. A malfunction in the aileron actuator
B. The aileron lagging behind the movement of the wing during flexing
155
What is the purpose of control surface bias?
A. To maintain constant input from the pilot
B. To apply a slight offset to control surfaces to achieve a desired flight attitude without constant pilot input
C. To neutralize all control inputs
B. To apply a slight offset to control surfaces to achieve a desired flight attitude without constant pilot input
156
How does a control surface bias assist during cruising flight?
A. It adjusts the control surfaces to maintain a specific pitch attitude without continuous pilot input
B. It requires constant back pressure on the control yoke
C. It eliminates the need for any trim adjustments
A. It adjusts the control surfaces to maintain a specific pitch attitude without continuous pilot input
157
What is aerodynamic balance concerned with?
A. The forces acting on a control surface from the center of pressure (CP)
B. The efficiency of the control surface during high-speed flight
C. The sensitivity of the control surface to pilot input
A. The forces acting on a control surface from the center of pressure (CP)
158
What is a horn balance?
A. A form of aerodynamic balance where a portion of the control surface moves into the wind during deflection, aiding the movement
B. A type of mass balance to prevent flutter
C. A type of spring tab that assists at higher speeds
A. A form of aerodynamic balance where a portion of the control surface moves into the wind during deflection, aiding the movement
159
What is the function of an inset hinge in aerodynamic balance?
A. It helps reduce the control surface's sensitivity
B. It positions the control surface behind the leading edge to assist in deflection
C. It prevents aerodynamic forces from acting on the control surface
B. It positions the control surface behind the leading edge to assist in deflection
160
What does the balance panel assist with?
A. It helps reduce control surface weight
B. It creates a pressure difference on the control surface, assisting in deflection
C. It makes the control surface less sensitive to pilot inputs
B. It creates a pressure difference on the control surface, assisting in deflection
161
What is the role of seals in a balance panel?
A. To increase drag on the control surface
B. To separate the chambers in front of the control surface and ensure the pressure difference is maintained
C. To reduce the aerodynamic load on the control surface
B. To separate the chambers in front of the control surface and ensure the pressure difference is maintained
162
What is the speed of sound at sea level in the international standard atmosphere at 15°C?
A. 340 m/s or 760 mph
B. 295 m/s or 660 mph
C. 400 m/s or 900 mph
A. 340 m/s or 760 mph
163
What is the definition of the Mach number?
A. The speed of an aircraft relative to the speed of sound in the same medium
B. The ratio of an aircraft’s altitude to its speed
C. The difference between the aircraft’s speed and the speed of sound
A. The speed of an aircraft relative to the speed of sound in the same medium
164
In which region does an aircraft experience both subsonic and supersonic airflow?
A. Subsonic region
B. Supersonic region
C. Transonic region
C. Transonic region
165
What is the typical range of Mach numbers for subsonic flight?
A. Mach 0 to Mach 0.8
B. Mach 0.8 to Mach 1.2
C. Mach 1.2 to Mach 5
A. Mach 0 to Mach 0.8
166
What happens during transonic flight as the aircraft approaches Mach 1?
A. The entire aircraft moves into supersonic flow
B. Shock waves form at the leading edge of the wing
C. The airflow is completely smooth with no turbulence
B. Shock waves form at the leading edge of the wing
167
What is the primary effect of shock waves during transonic flight?
A. Increased airflow around the wing
B. Airflow separation and a shift in the center of lift leading to a nose-down pitch tendency
C. Decreased drag and increased lift
B. Airflow separation and a shift in the center of lift leading to a nose-down pitch tendency
168
Which flight region is characterized by all airflow around the aircraft being supersonic?
A. Subsonic flight
B. Supersonic flight
C. Transonic flight
B. Supersonic flight
169
What occurs to the shock wave during supersonic flight?
A. It moves from the aircraft's rear to the leading edge
B. It remains near the wing's leading edge
C. It moves to the rear of the aircraft and attaches to the trailing edge
C. It moves to the rear of the aircraft and attaches to the trailing edge
170
In supersonic flight, what happens to the coefficient of lift and drag compared to subsonic flight?
A. The coefficient of lift increases and drag decreases
B. The coefficient of lift decreases and drag increases
C. The coefficient of lift and drag both remain the same
B. The coefficient of lift decreases and drag increases
171
At what Mach number does supersonic flight begin?
A. Mach 0.8
B. Mach 1.2
C. Mach 5.0
B. Mach 1.2
172
Which of the following best describes subsonic flight?
A. Airflow is highly compressible, leading to changes in air density and pressure
B. The speed of sound is exceeded, leading to shock wave formation
C. Airflow is approximated as incompressible, with small changes in density and pressure
C. Airflow is approximated as incompressible, with small changes in density and pressure
173
What causes compressibility effects in supersonic flight?
A. The airflow becoming incompressible
B. The pressure and density of the air changing with no noticeable change in air density
C. Air flowing smoothly without shock waves
B. The pressure and density of the air changing with no noticeable change in air density
174
Which Mach number range is considered supersonic flight?
A. Mach 0.8 to 1.2
B. Mach 1.2 to 5.0
C. Mach 5.0 to 10.0
B. Mach 1.2 to 5.0
175
What is the definition of the Mach number?
A. The ratio of the speed of an object to the local speed of sound
B. The speed of sound relative to the aircraft
C. The difference between the aircraft's speed and the speed of sound
A. The ratio of the speed of an object to the local speed of sound
176
If an aircraft is flying at a Mach number of 0.6, what does this mean?
A. The aircraft is flying at 60% of the speed of sound
B. The aircraft is flying at the speed of sound
C. The aircraft is flying faster than the speed of sound
A. The aircraft is flying at 60% of the speed of sound
177
What is the critical Mach number?
A. The speed at which the aircraft exceeds the speed of sound
B. The lowest Mach number at which the airflow around some point of the aircraft reaches the speed of sound
C. The Mach number at which shock waves start to dissipate
B. The lowest Mach number at which the airflow around some point of the aircraft reaches the speed of sound
178
In the context of critical Mach number, what is meant by "local Mach number"?
A. The Mach number of the aircraft as a whole
B. The speed of the airflow over certain parts of the aircraft, such as the wing, relative to the local speed of sound
C. The Mach number at the aircraft’s tail
B. The speed of the airflow over certain parts of the aircraft, such as the wing, relative to the local speed of sound
179
When an aircraft approaches its critical Mach number, what effect does this have?
A. The aircraft becomes unstable and experiences high turbulence
B. Compressibility effects occur, and shock waves begin to form
C. The aircraft enters a supersonic flight region
B. Compressibility effects occur, and shock waves begin to form
180
If an aircraft is flying at Mach 0.6, and the local Mach number at some point reaches Mach 0.8, what does this indicate?
A. The aircraft is flying faster than the speed of sound
B. The aircraft is experiencing supersonic airflow over some parts of the aircraft
C. The entire aircraft is experiencing supersonic flow
B. The aircraft is experiencing supersonic airflow over some parts of the aircraft
181
At what Mach number is the local Mach number equal to the speed of sound?
A. Mach 0.8
B. Mach 1.0
C. Mach 1.2
B. Mach 1.0
182
What happens when the aircraft's speed reaches the critical Mach number (MCrit)?
A. The aircraft transitions into supersonic flight
B. Some parts of the aircraft experience local supersonic flow and shock waves form
C. The aircraft's speed reduces automatically to subsonic levels
B. Some parts of the aircraft experience local supersonic flow and shock waves form
183
What is the relationship between the local Mach number and the aircraft’s speed?
A. The local Mach number is always the same as the aircraft's speed
B. The local Mach number can be higher than the aircraft’s speed due to airflow acceleration over the wing
C. The local Mach number is always lower than the aircraft's speed
B. The local Mach number can be higher than the aircraft’s speed due to airflow acceleration over the wing
184
What is the typical speed of sound at sea level in standard conditions?
A. 300 m/s
B. 340 m/s
C. 400 m/s
B. 340 m/s
185
What effect is commonly experienced as an aircraft approaches its critical Mach number?
A. Reduced drag and lift
B. Formation of shock waves and aerodynamic drag increase
C. The aircraft's center of lift moves forward
B. Formation of shock waves and aerodynamic drag increase
186
What does a Mach number of 1 indicate for an aircraft?
A. The aircraft is traveling at 100% of the speed of sound
B. The aircraft is flying at subsonic speeds
C. The aircraft is moving faster than the speed of sound
A. The aircraft is traveling at 100% of the speed of sound
187
At what Mach number does air begin to be considered compressible?
A. Mach 0.2
B. Mach 0.4
C. Mach 1.0
B. Mach 0.4
188
What are the undesirable effects experienced as an aircraft enters the transonic range?
A. Increased lift and reduced drag
B. Sudden rise in drag, reduced lift, buffeting, and control problems
C. Increase in stability and smooth flight
B. Sudden rise in drag, reduced lift, buffeting, and control problems
189
What forms when an aircraft's speed reaches the speed of sound?
A. A bow shock wave
B. A steady airflow
C. A compressibility wave
A. A bow shock wave
190
When the aircraft’s speed exceeds the speed of sound, what happens to the pressure waves?
A. They travel ahead of the aircraft
B. They radiate behind the aircraft
C. They disappear completely
B. They radiate behind the aircraft
191
How does a boat moving through water compare to shock wave formation?
A. The boat forms a bow wave only if it moves faster than the wave speed
B. The boat never forms a wave
C. The boat forms waves regardless of its speed
A. The boat forms a bow wave only if it moves faster than the wave speed
192
What is the primary characteristic of a "normal shock wave" in transonic flight?
A. It occurs at the trailing edge of the wing
B. It forms at right angles to the airflow path
C. It only appears at supersonic speeds
B. It forms at right angles to the airflow path
193
As the aircraft’s speed increases above the speed of sound, what happens to shock waves?
A. They move forward towards the aircraft’s nose
B. They move rearwards towards the trailing edge
C. They dissipate into the air
B. They move rearwards towards the trailing edge
194
What effect does the boundary layer have behind shock waves?
A. The flow becomes more streamlined
B. The boundary layer thickens and may cause flow separation
C. The boundary layer becomes thinner and more efficient
B. The boundary layer thickens and may cause flow separation
195
What is 'wave drag'?
A. Drag caused by air resistance only
B. Drag due to shock waves that result from compressibility effects
C. Drag caused by wing lift
B. Drag due to shock waves that result from compressibility effects
196
How can wave drag be reduced?
A. By adding more engines
B. By using vortex generators and applying the area rule
C. By increasing the aircraft's speed
B. By using vortex generators and applying the area rule
197
What is the function of vortex generators on an aircraft?
A. To increase the airflow speed
B. To reduce the boundary layer thickness and wave drag
C. To decrease fuel consumption
B. To reduce the boundary layer thickness and wave drag
198
What is the Area Rule primarily used for?
A. To reduce drag at high speeds in supersonic flight
B. To increase lift during transonic flight
C. To increase stability at subsonic speeds
A. To reduce drag at high speeds in supersonic flight
199
What is the Sears-Haack body known for?
A. The body with the least drag at subsonic speeds
B. The shape with the lowest theoretical wave drag in supersonic flow
C. A body that reduces noise at high speeds
B. The shape with the lowest theoretical wave drag in supersonic flow
200
How does the cross-sectional area of an aircraft affect wave drag?
A. Large changes in cross-sectional area increase wave drag
B. Small changes in cross-sectional area reduce wave drag
C. The cross-sectional area does not impact wave drag
A. Large changes in cross-sectional area increase wave drag
201
What is the effect of aerodynamic heating during supersonic flight?
A. The increase in temperature is negligible
B. The temperature increases rapidly, potentially weakening materials
C. It only affects the aircraft's paint and surface
B. The temperature increases rapidly, potentially weakening materials
202
Why are some parts of supersonic aircraft made from titanium alloy?
A. To reduce weight and handle higher temperatures without losing strength
B. To make the aircraft more fuel-efficient
C. To improve aerodynamics at subsonic speeds
A. To reduce weight and handle higher temperatures without losing strength
203
What happens to the strength of aluminum alloy as temperature increases to 250°C?
A. Its strength increases significantly
B. Its strength remains the same
C. Its strength decreases by approximately 80%
C. Its strength decreases by approximately 80%
204
What is the approximate skin temperature of the Concorde at Mach 2?
A. 50°C
B. 100°C
C. 250°C
C. 250°C
205
How does the center of lift change in supersonic flight compared to subsonic flight?
A. It moves closer to the tail in supersonic flight
B. It moves further from the center of gravity in supersonic flight
C. It remains in the same position regardless of speed
B. It moves further from the center of gravity in supersonic flight
206
What happens to the total drag of an aircraft above its critical Mach number?
A. It decreases
B. It stays constant
C. It increases significantly due to wave drag
C. It increases significantly due to wave drag
207
What is the primary function of a gas turbine engine compressor in supersonic flight?
A. To increase axial velocity above Mach 0.4
B. To slow the air entering the compressor to subsonic velocity
C. To increase the rotational speed of the compressor blades
B. To slow the air entering the compressor to subsonic velocity
208
At flight speeds just above Mach 1, what modification is required for the engine inlet design?
A. A single normal shock wave diffuser is enough
B. A multiple oblique shock wave is required
C. No modifications are needed
A. A single normal shock wave diffuser is enough
209
Why is the normal shock diffuser inlet not suitable for high supersonic speeds?
A. It causes a significant reduction in total pressure recovery
B. It increases fuel consumption
C. It leads to excessive engine temperature
A. It causes a significant reduction in total pressure recovery
210
How does air behave in a converging duct at supersonic speeds?
A. The velocity increases, and static pressure decreases
B. The velocity decreases, and static pressure increases
C. The air chokes, decelerates, and compresses, with a rise in pressure
C. The air chokes, decelerates, and compresses, with a rise in pressure
211
What happens in a divergent duct at supersonic speeds?
A. The airflow decelerates, and the pressure increases
B. The airflow accelerates, and the pressure decreases
C. The airflow stays constant, and pressure remains unchanged
B. The airflow accelerates, and the pressure decreases
212
What is the role of a converging/diverging duct in supersonic airflow?
A. It helps to stabilize the airflow and minimize pressure loss
B. It helps to accelerate the airflow and control shock waves
C. It maintains constant airflow velocity regardless of pressure changes
B. It helps to accelerate the airflow and control shock waves
213
What is the function of the oblique shock inlet design in supersonic air intake?
A. It uses a single normal shock to slow the supersonic airflow
B. It forms an external oblique shock wave to slow the airflow before the normal shock occurs
C. It reduces airflow velocity without any pressure loss
B. It forms an external oblique shock wave to slow the airflow before the normal shock occurs
214
How does the multiple oblique shock inlet differ from the single oblique shock inlet?
A. It uses fewer shock waves and decelerates the airflow more abruptly
B. It uses a series of weak oblique shock waves to gradually slow the airflow
C. It does not use any shock waves and relies on pressure gradients only
B. It uses a series of weak oblique shock waves to gradually slow the airflow
215
Why is using multiple oblique shock waves beneficial in supersonic intake design?
A. It results in higher drag
B. It reduces energy waste and provides the highest-pressure recovery
C. It increases the strength of the normal shock wave
B. It reduces energy waste and provides the highest-pressure recovery
216
What is the role of variable supersonic inlets?
A. To adjust the inlet's geometry for different flight conditions and speeds
B. To maintain a fixed shock wave pattern regardless of speed
C. To maximize airflow velocity at all Mach numbers
A. To adjust the inlet's geometry for different flight conditions and speeds
217
How does a variable supersonic inlet operate at speeds just above Mach 1?
A. The inlet remains fully open with no shock waves
B. The actuators create a single normal shock wave, similar to the normal shock diffuser inlet
C. The actuators adjust the inlet to create a constant supersonic airflow
B. The actuators create a single normal shock wave, similar to the normal shock diffuser inlet
218
How do actuators in a variable supersonic inlet affect the airflow at high Mach numbers?
A. They reduce airflow velocity to subsonic speeds
B. They use three oblique shock waves followed by a normal shock to slow the airflow
C. They increase the airflow speed to supersonic levels
B. They use three oblique shock waves followed by a normal shock to slow the airflow
219
At which Mach number is the engine inlet fully open with a high angle of attack (AOA)?
A. Below Mach 1
B. Above Mach 1
C. At Mach 2
A. Below Mach 1
220
How does the design of a supersonic inlet change with the Mach number?
A. It stays the same regardless of speed
B. It adapts to suit different flow directions and Mach numbers
C. It only changes at speeds above Mach 2
B. It adapts to suit different flow directions and Mach numbers
221
What is the main goal of the supersonic inlet design in terms of energy efficiency?
A. To maximize the velocity of incoming air
B. To slow the air with minimal waste of energy and pressure loss
C. To increase the temperature of the air for better combustion
B. To slow the air with minimal waste of energy and pressure loss
222
How does sweepback increase the critical Mach number of an aircraft?
A. By increasing the thickness of the wing profile
B. By reducing the thickness aerodynamically, delaying the formation of shock waves
C. By shortening the chord length
B. By reducing the thickness aerodynamically, delaying the formation of shock waves
223
What is the effect of using a thinner wing profile at a given Mach number?
A. It results in a larger shock wave
B. It delays the critical Mach number and forms a smaller incipient shock wave
C. It causes a faster formation of shock waves
B. It delays the critical Mach number and forms a smaller incipient shock wave
224
What is the primary function of wings in jet aircraft?
A. To carry the aircraft's fuel and reduce drag
B. To carry weight and house fuel tanks
C. To increase the aircraft's speed at high altitudes
B. To carry weight and house fuel tanks
225
How does the sweep angle affect the thickness of the wing profile?
A. It increases the wing profile thickness
B. It reduces the effective thickness aerodynamically by increasing the chord length
C. It has no effect on the thickness
B. It reduces the effective thickness aerodynamically by increasing the chord length
226
What is the typical sweep angle of wings on modern jet aircraft?
A. 10°
B. 15°
C. 30°
C. 30°
227
What happens to the aerodynamic properties of a wing as the sweep angle increases to 30°?
A. The thickness reduces, and the critical Mach number increases
B. The thickness increases, and the critical Mach number decreases
C. The wing loses stability and reduces lift
A. The thickness reduces, and the critical Mach number increases
228
What are the components of the airflow speed vectors (V) over a swept wing?
A. Chordwise flow and spanwise flow
B. Longitudinal and lateral flow
C. Forward and upward flow
A. Chordwise flow and spanwise flow
229
Where does the normal incipient shock wave form on a swept wing?
A. Along the chordwise direction, at right angles to Vn
B. Along the spanwise direction, at right angles to Vt
C. Along the span at right angles to the chordwise flow, in line with Vn
C. Along the span at right angles to the chordwise flow, in line with Vn
230
How do swept wings reduce the overall drag of an aircraft?
A. By increasing the frontal area and reducing wingtip effects
B. By reducing the frontal area, profile drag, and improving lateral stability
C. By adding more weight to the wing
B. By reducing the frontal area, profile drag, and improving lateral stability
231
What is the risk associated with swept wings regarding wingtip stall?
A. It causes the centre of pressure to move backward, increasing drag
B. It can cause stagnation in the boundary layer, resulting in wingtip stall and instability
C. It leads to a reduced critical Mach number
B. It can cause stagnation in the boundary layer, resulting in wingtip stall and instability
232
How does wingtip stall affect the centre of pressure on an aircraft?
A. It moves the centre of pressure backward, away from the centre of gravity
B. It causes the centre of pressure to move forward, closer to the centre of gravity
C. It has no impact on the centre of pressure
B. It causes the centre of pressure to move forward, closer to the centre of gravity
233
What devices are used to prevent wingtip stall caused by sweepback?
A. Wing fences, vortex generators, and sawtooth leading edges
B. Flaps, slats, and ailerons
C. Spoilers and rudders
A. Wing fences, vortex generators, and sawtooth leading edges
234
How does sweepback help in delaying the formation of shock waves at transonic speeds?
A. By increasing the wing thickness
B. By reducing the effective aerodynamic velocity, delaying the critical Mach number
C. By increasing the flow speed over the wing
B. By reducing the effective aerodynamic velocity, delaying the critical Mach number
235
What is one of the disadvantages of swept wings?
A. Reduced stability at high speeds
B. Increased spanwise flow, leading to stagnation and wingtip stall
C. Higher drag at low speeds
B. Increased spanwise flow, leading to stagnation and wingtip stall
236
Why is it difficult to recover from wingtip stall?
A. Because the centre of pressure moves too far back
B. Because the centre of pressure moves forward, close to the centre of gravity, making recovery challenging
C. Because the stall is too weak to affect flight performance
B. Because the centre of pressure moves forward, close to the centre of gravity, making recovery challenging
