Aviation Information Flashcards
(148 cards)
1
Q
What are the two edges of an airfoil called?
A
- Leading edge
- Trailing edge
2
Q
What are airfoils used for?
A
To push air to create lift
3
Q
How does an airfoil provide lift?
A
Based on Benoulli’s Principle. The air flows faster over the top of the wing that it does underneath thus creating more pressure under the wing and providing lift.
4
Q
What are two categories of fixed-wing propulsion systems?
A
- Propellers
- Jets
5
Q
What are the different kinds of weight in aviation?
A
- Basic weight
- Operating weight
- Gross weight
- Landing gross weight
- Zero fuel weight
6
Q
What is profile drag?
A
Frictional resistance of helicopter blades passing through the air.
7
Q
What is induced drag?
A
Airflow circulation around the blades creating vortices.
8
Q
What is flight attitude?
A
A/C changes it’s position in flight
9
Q
What is the axis that runs lengthwise from the nose to the tail?
A
Longitudinal axis
10
Q
What is the axis that runs wingtip to wingtip?
A
Lateral axis
11
Q
What is the axis that runs through the A/C’s center of gravity?
A
Vertical axis
12
Q
What is the movement on the A/C’s longitudinal axis called?
A
Roll
13
Q
What is the movement on the A/C’s lateral axis called?
A
Pitch
14
Q
What is the movement on the A/C’s vertical axis called?
A
Yaw
15
Q
What are type types of flight controls?
A
- Primary
- Secondary
16
Q
What are the 4 main types of helicopter flight controls?
A
- Cyclic
- Collective
- Anti-torque pedals
- Throttle
17
Q
What does the altimeter measure?
A
Height above a particular air pressure level and provides altitude above ground.
18
Q
What unit of measure does the altimeter use?
A
Feet
19
Q
What is the standard barometric pressure?
A
29.92 inches of mercury
20
Q
What is the standard sea level free air temperature?
A
59 deg F
21
Q
What are the 5 types of altitude?
A
- Indicated Altitude
- True Altitude
- Absolute Altitude
- Pressure Altitude
- Density Altitude
22
Q
What is indicated altitude?
A
Uncorrected altitude
23
Q
What is true altitude?
A
Distance above Mean Sea Level (MSL)
24
Q
What is absolute altitude?
A
Distance above terrain or ground level
25
What is pressure altitude?
Adjusted to standard barometric pressure (29.92)
26
What is density altitude?
Corrected for variations from standard temperature. Important altitude for A/C's performance.
27
What is hypoxia?
Caused by insufficient oxygen in the bloodstream from unpressurized flight at high altitude
28
What is the FAA regulation for requiring oxygen in flights?
Above 12,500 feet
29
What is the military regulation for requiring oxygen in flights?
Above 10,000 feet
30
What does the Vertical Speed Indicator (VSI) do?
Indicates when the A/C is climbing, descending or level flight.
31
What does the Airspeed Indicator do?
Measures the difference between impact pressure and static pressure.
32
What are the 4 types of airspeeds? (ICE-T)
1. Indicated Airspeed
2. Calibrated Airspeed
3. Equivalent Airspeed
4. True Airspeed
33
What is indicated airspeed?
Measures air pressure from the pitot tube
34
What is calibrated airspeed?
Accounting for A/C mechanical and position errors
35
What is equivalent airspeed?
Compensating for compression effects; used at speeds over 200mph
36
What is true airspeed?
Accounting for temperature and atmospheric pressure changes
37
What are the two types of turn indicators?
- Turn and slip
| - Turn coordinator
38
What unit of measure does the turn indicator use?
Degrees per second
39
What is the inclinometer? How is it used?
Liquid-filled curved tube with a ball inside. Used to show A/C yaw and side-to-side movement.
40
What is the artificial horizon indicator?
Also known as attitude indicator. Displays picture of the attitude of the A/C.
41
What are the 2 types of compasses used in an A/C?
- Magnetic compass (old)
| - Vertical card compress (new)
42
What 4 forces act on an A/C in flight?
- Lift
- Gravity
- Thrust
- Drag
43
What effects density altitude?
- Temperature
- Atmospheric pressure
- Humidity
- Altitude
44
What maneuver in which a rotary wing A/C is maintained in nearly motionless flight over a ground reference point at a constant altitude and heading is known as?
Hovering
45
The flight envelope of an A/C is?
The region of altitude and airspeed in which it can be operated
46
An airfoil's efficiency, either a wing or a rotor blade, is ________ at high altitudes by the __________ air density?
Decreased, lesser
47
The primary purpose of the tail rotor system is to?
Balance or counteract the torque effect of the main rotor
48
Takeoff from a slope in a helicopter with skid-typer landing gear is normally done by?
Bringing the A/C to a level altitude
49
A helicopter's cyclic control is a mechanical linkage used to change the pitch of the main rotor blades?
At a selected point in it's circular pathway
50
When the rotor blades of a helicopter are spinning fast enough in a clockwise direction to generate lift, what phenomenon causes the body of the helicopter to have a tendency to turn in a counterclockwise direction?
Autorotation
51
The differential in lift between that of the advancing rotor blade and that of the retreating rotor blade is called?
Dissymmetry of lift
52
Foot pedals in the helicopter give the pilot the ability to?
Control the torque effect
53
What does the cyclic control do?
Direction of tilt of the main rotor
54
Moving the cyclic forward and simnifically raising the collective will cause the helicopter to?
Increase it's forward speed and begin to climb
55
Conventional American helicopters have a main rotor that?
Turns in a counterclockwise direction
56
Translational lift is?
The additional lift gained when the helicopter leaves it's downwash
57
Gyroscopic precession happens when?
A force applied to a spinning disc has it's effect 90 degrees later in the direction and plane of rotation
58
One useful tool for illustration of aerodynamic forces at work is a vector which is a?
Quantity with a magnitude and a direction
59
As a rotor system beings to turn, the blades start to rise from their drooping position due to?
Centrifugal force
60
Significant "coning" of the rotor disk can cause?
A decrease in lift due to a decrease in effective disk area
61
In tandem rotor and coaxial helicopters?
The two rotor systems turn in opposite directions, canceling the torque effect
62
Most American-built single-rotor helicopter turn the main rotor?
In a counterclockwise direction
63
An increase in blade pitch through application of collective?
Generates the additional lift needed to hover
64
"Ground effect" is ____________ rotor system efficiency due to interference of the airflow ____________?
Increased, when near the ground
65
The collective pitch control is used to?
Make simultaneous changes to the pitch angle of the main rotor blades
66
A twist grip throttle is usually mounted?
On the end of the collective lever
67
With the anti-torque pedals in the neutral position, the tail rotor has a medium positive pitch angle, thereby?
Approximately equaling the torque of the main rotor
68
Main rotor systems are classified as rigid, semirigid, or fully articulated according to?
How the main rotor blades are attached and move relative to the main rotor hub.
69
The lift generated by an airfoil directly depends on what factors?
- Airflow speed
- Air density
- Total area of the segment or airfoil
- Angle of attack between the air and airfoil
70
The angle between the chord line of a wing or airfoil and the direction of relative wind or airflow is called the?
Angle of attack
71
When the pilot of a fixed-wing A/C pushes forward on the control stick, the elevators will
move downward
72
Another form of the anti-torque system is the "fan-in-tail" system or fenestron?
Uses a series of rotating blades shrouded within a vertical tail
73
What helicopters use specific engines because they are relatively simple and inexpensive to operate?
Training helicopters use reciprocating (piston) engines
74
What does VFR stand for?
Visual Flight Rules (VFR)
75
If a helicopter's center of gravity (CG) is too far forward of the rotor must?
- Have a nose-low attitude during hover.
- Be unable to decelerate sufficiently to bring A/C to a stop.
- Have excessive rearward cyclic displacement may be needed to maintain a hover when there is no wind.
76
What is a disadvantage of a single main rotor helicopter?
The secondary rotor diverts power to counter torque, rather than being used for lift
77
Thrust is created by what?
The engine(s) of a helicopter
78
Which are some commonly used helicopter taxi maneuvers?
- Air Taxi
- Ground Taxi
- Hover Taxi
79
Angle of incidence is a mechanical angle between?
The chord line of the blade and the circular plane in which it rotates
80
Blade flapping is used during takeoff to?
Counter dissymmetry of lift
81
Airfoils are used to?
Regulate airflow
82
Settling with power is also known as?
Vortex ring state
83
By moving a cyclic, a pilot is able to?
Alter the pitch of main rotor blades
84
What is the role of the engine?
Drives power upward through the mast to the rotor blades which are controlled by the pilot
85
What direction does the main rotor rotate in US, UK & Germany helicopters?
Counter-clockwise
86
What is the main advantage of a helicopter over an airplane?
Takeoff vertically
87
What are some tasks helicopters perform?
Dropping cargo or troops into challenging conditions
88
What is a disadvantage of single main rotor helicopters?
Some power is used for countering torque, rather than being used solely for lift
89
What type of helicopter is the fastest and most powerful?
Tandem rotor helicopters
90
What direction do coaxial rotor helicopter blades spin?
They rotate in opposite directions to each other
91
What is an advantage of a coaxial rotor helicopter?
Reducing payload and allowing greater cargo and passenger capacity
92
How is thrust generated?
By the helicopter engine(s)
93
What is drag?
A force that acts against thrust
94
What causes drag?
Shape and size of the aircraft disrupting the flow of air as it travels
95
What is Form drag?
Increases as the speed of the helicopter increases
96
What is Skin friction?
Microscopic roughness of the helicopter blades
97
How does induced drag increase and decrease?
- Increases by the A/C flying at lower speeds.
| - Decreases when the A/C is flying at higher speeds.
98
What is parasite drag?
Created by the A/C components that are external to the fuselage.
99
What is total drag?
Sum total of profile, induced and parasite drag.
100
What does the lowest total drag offer?
- Maximum endurance
- Best rate of climb
- Minimum rate of descent in autorotation
101
What is weight?
Force from combined mass of the A/C acted upon by gravity.
102
What are some causes of weight of an A/C to increase?
- Banking (curved flight path)
| - Flying into unexpected gusts
103
How does a pilot counteract an increase in weight while in flight?
Increase thrust
104
What is lift?
Upward force created by spinning A/C blades allowing air to pass over them.
105
What is angle of attack (AOA)?
Angle of the A/C blade's direction of movement relative to the air.
106
What happens when the AOA is favorable?
More lift is produced
107
What happens when the AOA is not optimum?
More drag is introduced
108
What is the angle of incidence?
Also known as blade pitch, intersection of the chord line with the plane of rotation.
109
What is the Venturi Flow?
Amount of energy within a closed system that does not change form.
110
What happens when a pilot moves the cyclic?
Alter the pitch of the main rotor blades which causes thrust in a certain direction.
111
What A/C control is used to increase or decrease altitude or airspeed?
Collective
112
What do anti-torque pedals do when pressed?
Adjust pitch of the tail rotor which alters the amount of thrust produced. Also changes the direction of the nose of the A/C.
113
What happens when the pilot adjusts the throttle control?
Increase or decrease the amount of power generated by the engine resulting in sufficient lift for flight.
114
What are the four basic flight maneuvers?
- Straight and level flight
- Truns
- Climbs
- Hovering
115
When does hover taxiing occur?
25 feet or less above ground
116
When does air taxiing occur?
100 feet or less and requires the pilot to avoid flying over people, vehicles and other aircrafts
117
What Army A/C is four-bladed with a single main rotor?
Sikorsky UH-60 Blackhawk
118
When was the Sikorsky UH-60 Blackhawk introduced?
1979
119
What Army A/C has twin engines and tandem rotors?
Boeing CH-47 Chinook
120
When was the Boeing CH-47 Chinook introduced?
1962
121
What is the top speed of the Boeing CH-47 Chinook?
196 mph
122
What Army A/C is supported by a twin turboshaft?
Boeing AH-64 Apache
123
When was the Boeing AH-64 Apache introduced?
1986
124
What Army A/C has a single engine and single main rotor?
Belt OH-58 Kiowa
125
When was the Belt OH-58 Kiowa introduced?
1969
126
What points does a helicopter generate a maximum and minimum airflow velocity?
```
Maximum = 3 o'clock position
Minimum = 9 o'clock position
```
127
What is an airfoil?
Surface that contributes to airlift generation by regulating airflow over it's upper and lower surface
128
What is autorotation?
Situation in flight of an airborne helicopter. When air lift is generated by the air flowing across it's blades.
129
What does autorotation allow a pilot to do?
Land the A/C without crashing it
130
What emergency procedure are pilots trained to use to avoid crashes?
Freewheeling feature for autorotation.
131
What is TAF?
Total Aerodynamic Force
132
How is blade flapping caused?
By greater airlift during hovering
133
What is the definition of blade span?
Distance between tip of the blade and the drive shaft
134
What is the definition of blade twist?
Design feature of a blade to distribute airlift evenly throughout the airfoil.
135
What is dissymmetry of lift?
Occurs when the helicopter takes off because the difference in forces by advancing and retreating blades.
136
What is In Ground Effect?
Airstream around the spinning rotor blades that provide extra lift when close to the ground.
137
What is Settling with Power?
State of helicopter flight when it descends vertically downward at a rate of 5 fps and low forward speed.
138
Thrust is transferred into motion via?
The mast and rotor(s)
139
Parasite drag slows a helicopter by?
Opposing thrust
140
How does banking impact weight?
Increases weight
141
Lift gives a helicopter altitude by?
Overcoming weight
142
The main tactical knowledge of a helicopter over an airplane is?
The ability to takeoff and land in places not possible for airplanes
143
Tandem rotor helicopters do not require a tail rotor due to?
Countering torque
144
The throttle is primarily used to?
Alter power generated by the engine
145
Climbs and descents are achieved by?
Manipulating the nose direction
146
Coaxial rotor helicopters feature?
Two sets of blades mounted on the same mast, counter rotating
147
Angle of attack is influenced by?
A combination of pilot control and external factors
148
Hovering occurs when?
Lift is equal to weight
