Worksheetsmod 4
Total questions: 88
Worksheet time: 3hrs 56mins
Name
Class
Date
1.
The rotor of a helicopter provides three basic fiunctions:
a)
a) generation of vertical lifting force(thrust) in oppose to aircraft weight b) generation of horizontal propulsive force for forward flight c) Means of generating forces and moments to control the altitude and position of the helicopter.
b)
retarding force created by development of lift and the movement of an object through the air
c)
is defined as flowing parallel, opposite the axis of rotation of the rotor and distinctly perpendicular to the leading edge of the rotor blade.
d)
As disc loading increases, greater the ________ you need to control the speed of the rotor.
2.
Airfoil
a)
The direction of the relative wind is relative to the attitude, or position, of the airfoil and is always parallel, equal, and opposite in direction to the ___________.
b)
provides aerodynamic force when it interacts with a moving stream of air.
c)
distance from the rotor hub to the blade tip.
d)
The production of _____ is based upon the airfoil creating circulation in the airstream (Magnus Effect) and creating differential pressure on the airfoil (Bernoulli's Principle).
3.
Symmetrical
a)
the curvature of the airfoil's upper and lower surfaces.
b)
opposes lift and is caused by the downward pull of gravity.
c)
this type of airfoil is very stable, which helps keep the blade twisting and flight control loads to a minimum.
d)
The result of this effect is a tendency for the helicopter to roll slightly to the right as it accelerates through approximately 20 knots or if the headwind is approximately 20 knots.
4.
Symmetrical
a)
retarding force created by development of lift and the movement of an object through the air
b)
When a helicopter is at rest, the blades will ________ because of a lack of centrifugal stiffening.
c)
provides aerodynamic force when it interacts with a moving stream of air.
d)
meaning both the upper and the lower surfaces had the same camber (curvature)
5.
droop
a)
In fluid dynamics, the momentum theory or disk actuator theory is a theory describing a mathematical model of an ideal actuator disk, such as a propeller or helicopter rotor, by _________ , _______ and _________.
b)
provides aerodynamic force when it interacts with a moving stream of air.
c)
When a helicopter is at rest, the blades will droop because of a lack of _______________.
d)
When a helicopter is at rest, the blades will ________ because of a lack of centrifugal stiffening.
6.
centrifugal stiffening
a)
When a helicopter is at rest, the blades will droop because of a lack of _______________.
b)
the ratio of the load supported by the main rotor system to the actual weight of the helicopter and its contents.
c)
It is caused by the fact that in directional flight the aircraft relative wind is added to the rotational relative wind on the advancing blade and subtracted on the retreating blade.
d)
As the induced flow increases, the angle of attack _________.
7.
Droop Stops
a)
When a helicopter is at rest, the blades will ________ because of a lack of centrifugal stiffening.
b)
occurs as the rotor blades begin to lift the weight of the helicopter.
c)
these are used to prevent the blades from hitting the fuselage when starting up or shutting down.
d)
A single main rotor helicopter, during the hovering flight, appears to drift in the same direction as the thrust of antitorque rotor. This drifting tendency is called ______________________.
8.
Droop Stops
a)
The direction of this wind is relative to the attitude, or position, of the airfoil and is always parallel, equal, and opposite in direction to the flight path.
b)
used to limit blade travel both up and down.
c)
refers to a principle of gyroscopes that states when a force is applied to a spinning object, the maximum reaction occurs approximately 90 degrees later in the direction of rotation.
d)
TRUE
9.
upwards stops
a)
utilized to restrict excessive blade sailing when starting the helicopter up in a wind.
b)
In a no-wind condition over a solid, smooth surface the ground effect is at its ____________.
c)
when the rotor blades speed up or slow down as the center of gravity moves closer or further away from the axis of rotation.
d)
an upward sweeping angle of the rotor blades as a result of lift and centrifugal force.
10.
Reflexing
a)
these are used to prevent the blades from hitting the fuselage when starting up or shutting down.
b)
the resulting movement or deflection of a rotating object when a force on this object is applied.
c)
done on asymmetrical airfoils wherein the trailing edge is bended to create the same features as symmetrical airfoils.
d)
when the rotor blades speed up or slow down as the center of gravity moves closer or further away from the axis of rotation.
11.
Blade Twist
a)
happens when it is hovering above the ground.
b)
refers to a changing chord line from the blade root to the tip.
c)
a significant consequence of thrust production.
d)
If you raise the bank angle to 60 ° while holding a steady altitude, the load factor _________________.
12.
Leading Edge
a)
the weight ratio to the total main rotor disk area, which is measured by dividing the total helicopter weight by the rotor disk area, which is the area swept by a rotor blades.
b)
the first part of the airfoil to meet the oncoming air.
c)
these are used to prevent the blades from hitting the fuselage when starting up or shutting down.
d)
provides aerodynamic force when it interacts with a moving stream of air.
13.
Trailing Edge
a)
aft portion where the airflow over the upper surface joins the airflow under the lower surface.
b)
done on asymmetrical airfoils wherein the trailing edge is bended to create the same features as symmetrical airfoils.
c)
happens when it is hovering above the ground.
d)
upward force created by the effect of airflow as it passes around an airfoil.
14.
Chord Line
a)
utilized to restrict excessive blade sailing when starting the helicopter up in a wind.
b)
An imaginary straight line from the leading edge to the trailing edge of an airfoil.
c)
_________ is used to mitigate the Coriolis effect.
d)
occurs as the rotor blades begin to lift the weight of the helicopter.
15.
Camber
a)
the curvature of the airfoil's upper and lower surfaces.
b)
a significant consequence of thrust production.
c)
upward force created by the effect of airflow as it passes around an airfoil.
d)
Two-bladed rotor systems are usually subject to Coriolis Effect to a much lower degree than articulated rotor systems because the blades are typically "__________" with respect to the rotor hub, and the shift in the center of mass distance from the rotation axis is minimal.
16.
Span
a)
A single main rotor helicopter, during the hovering flight, appears to drift in the same direction as the thrust of antitorque rotor. This drifting tendency is called ______________________.
b)
Since the fuselage of the helicopter, with a single main rotor, is suspended from a single point and has considerable mass, it is free to oscillate either longitudinally or laterally in the same way as a pendulum.
c)
distance from the rotor hub to the blade tip.
d)
In translational lift, if no corrections are made, the nose _______, and rolls to the _______.
17.
Angle of Attack
a)
angle between the blade chord line and the direction of the relative wind.
b)
this effect occurs less than one diameter of rotor above the surface.
c)
As the induced flow increases, the angle of attack _________.
d)
distance from the rotor hub to the blade tip.
18.
Relative Wind
a)
The lift and thrust generated by the rotor system act straight up for a helicopter to _____ and must be equal to the weight and drag that act straight down.
b)
wind moving past the airfoil.
c)
force that propels the helicopter through the air.
d)
When a helicopter is at rest, the blades will droop because of a lack of _______________.
19.
a)
This ratio provides a way of calculating a rotor system's ability to produce thrust.
b)
Translational lift is also present in a stationary hover.
c)
d)
If you raise the bank angle to 60 ° while holding a steady altitude, the load factor _________________.
20.
The direction of this wind is relative to the attitude, or position, of the airfoil and is always parallel, equal, and opposite in direction to the flight path.
a)
The direction of this wind is relative to the attitude, or position, of the airfoil and is always parallel, equal, and opposite in direction to the flight path.
b)
retarding force created by development of lift and the movement of an object through the air
c)
is defined as flowing parallel, opposite the axis of rotation of the rotor and distinctly perpendicular to the leading edge of the rotor blade.
d)
a condition when an aircraft is in straight-and-level, unaccelerated flight, and all forces are in balance.
21.
flight path
a)
The direction of the relative wind is relative to the attitude, or position, of the airfoil and is always parallel, equal, and opposite in direction to the ___________.
b)
The resultant of _________ determines the direction of movement of the helicopter.
c)
occurs as the rotor blades begin to lift the weight of the helicopter.
d)
utilized to restrict excessive blade sailing when starting the helicopter up in a wind.
22.
Blade Pitch Angle
a)
force that propels the helicopter through the air.
b)
when the rotor blades speed up or slow down as the center of gravity moves closer or further away from the axis of rotation.
c)
When a helicopter is at rest, the blades will ________ because of a lack of centrifugal stiffening.
d)
the angle between its chord line and the reference plane which contains the hub of the rotor.
23.
Collective Pitch
a)
In translational lift, if no corrections are made, the nose _______, and rolls to the _______.
b)
used to control the yaw of the helicopter.
c)
a condition when an aircraft is in straight-and-level, unaccelerated flight, and all forces are in balance.
d)
gives the rotor blade an equivalent amount of pitch no matter where it is in the plane of rotation (rotor disc) and is used to adjust the thrust of the rotor.
24.
Cyclic Pitch
a)
provides aerodynamic force when it interacts with a moving stream of air.
b)
In a steady-state flight, the helicopter has a load factor of ____, which means the main rotor system supports the helicopter 's actual total weight.
c)
Translational lift is also present in a stationary hover.
d)
shifts the pitch of each blade as a function of where it is in the plane of rotation.
25.
perpendicular
a)
The resultant of _________ determines the direction of movement of the helicopter.
b)
The only time that the axis of rotation and rotor mast coincide is when the tip-path plane is ________ to the rotor mast.
c)
Stall due to too high AOA.
d)
a) generation of vertical lifting force(thrust) in oppose to aircraft weight b) generation of horizontal propulsive force for forward flight c) Means of generating forces and moments to control the altitude and position of the helicopter.
26.
Axis-of-Rotation
a)
As disc loading increases, greater the ________ you need to control the speed of the rotor.
b)
is defined as flowing parallel, opposite the axis of rotation of the rotor and distinctly perpendicular to the leading edge of the rotor blade.
c)
In a no-wind condition over a solid, smooth surface the ground effect is at its ____________.
d)
The imaginary line about which the rotor rotates. It is represented by a line drawn through the center of, and perpendicular to, the tip-path plane.
27.
Tip-Path Plane
a)
The imaginary circular plane outlined by the rotor blade tips as they make a cycle of rotation.
b)
phenomenon affecting the rotor of a helicopter as it overcomes dissymmetry of lift through flapping
c)
can be recognized because of increased vibrations of the helicopter at airspeeds just below effective translational lift on takeoff and after passing through effective translational lift during landing.
d)
when the rotor blades speed up or slow down as the center of gravity moves closer or further away from the axis of rotation.
28.
LIFT
a)
- the downward force of the air.
b)
It is caused by the fact that in directional flight the aircraft relative wind is added to the rotational relative wind on the advancing blade and subtracted on the retreating blade.
c)
upward force created by the effect of airflow as it passes around an airfoil.
d)
the first part of the airfoil to meet the oncoming air.
29.
lift
a)
The direction of this wind is relative to the attitude, or position, of the airfoil and is always parallel, equal, and opposite in direction to the flight path.
b)
- the downward force of the air.
c)
As the rotor blades rotate, they generate what is called __________.
d)
The production of _____ is based upon the airfoil creating circulation in the airstream (Magnus Effect) and creating differential pressure on the airfoil (Bernoulli's Principle).
30.
LIFT
a)
As the induced flow increases, the angle of attack _________.
b)
a) generation of vertical lifting force(thrust) in oppose to aircraft weight b) generation of horizontal propulsive force for forward flight c) Means of generating forces and moments to control the altitude and position of the helicopter.
c)
accomplished by increasing the pitch angle of the main rotor blades.
d)
wind moving past the airfoil.
31.
Weight
a)
force that propels the helicopter through the air.
b)
meaning both the upper and the lower surfaces had the same camber (curvature)
c)
- the downward force of the air.
d)
opposes lift and is caused by the downward pull of gravity.
32.
increases
a)
When you bank a helicopter while maintaining a constant altitude, the "G" load or load factor __________.
b)
is the flight stage, where the main rotor system is turned by relative wind rather than engine power.
c)
this effect occurs less than one diameter of rotor above the surface.
d)
accomplished by increasing the pitch angle of the main rotor blades.
33.
THRUST
a)
where the efficiency of the hovering rotor system is improved with each knot of incoming wind gained by horizontal movement or surface wind.
b)
aft portion where the airflow over the upper surface joins the airflow under the lower surface.
c)
force that propels the helicopter through the air.
d)
the movement of the helicopter to the right due to the combination of main rotor torque and tail-rotor anti-torque.
34.
lift and thrust
a)
In a no-wind condition over a solid, smooth surface the ground effect is at its ____________.
b)
the first part of the airfoil to meet the oncoming air.
c)
The helicopter fuselage turns ______ as the engine turns the main rotor system in a counterclockwise direction.
d)
The resultant of _________ determines the direction of movement of the helicopter.
35.
antitorque pedals
a)
a condition when an aircraft is in straight-and-level, unaccelerated flight, and all forces are in balance.
b)
refers to a changing chord line from the blade root to the tip.
c)
used to control the yaw of the helicopter.
d)
- has an effect on the AOA.
36.
Torque
a)
a significant consequence of thrust production.
b)
rotor 's total lifting and thrust forces are perpendicular to the rotor 's tip-path plane or plane of rotation of the rotor.
c)
where the efficiency of the hovering rotor system is improved with each knot of incoming wind gained by horizontal movement or surface wind.
d)
The helicopter fuselage turns ______ as the engine turns the main rotor system in a counterclockwise direction.
37.
clockwise
a)
used to limit blade travel both up and down.
b)
provides aerodynamic force when it interacts with a moving stream of air.
c)
an upward sweeping angle of the rotor blades as a result of lift and centrifugal force.
d)
The helicopter fuselage turns ______ as the engine turns the main rotor system in a counterclockwise direction.
38.
DRAG
a)
It is caused by the fact that in directional flight the aircraft relative wind is added to the rotational relative wind on the advancing blade and subtracted on the retreating blade.
b)
In translational lift, if no corrections are made, the nose _______, and rolls to the _______.
c)
When a helicopter is at rest, the blades will droop because of a lack of _______________.
d)
retarding force created by development of lift and the movement of an object through the air
39.
DRAG
a)
provides aerodynamic force when it interacts with a moving stream of air.
b)
force that propels the helicopter through the air.
c)
rotor 's total lifting and thrust forces are perpendicular to the rotor 's tip-path plane or plane of rotation of the rotor.
d)
often caused by the induced drag experienced when the blades generate lift.
40.
Steady-State Flight
a)
a condition when an aircraft is in straight-and-level, unaccelerated flight, and all forces are in balance.
b)
when the rotor blades speed up or slow down as the center of gravity moves closer or further away from the axis of rotation.
c)
the curvature of the airfoil's upper and lower surfaces.
d)
Since the fuselage of the helicopter, with a single main rotor, is suspended from a single point and has considerable mass, it is free to oscillate either longitudinally or laterally in the same way as a pendulum.
41.
one
a)
aft portion where the airflow over the upper surface joins the airflow under the lower surface.
b)
is the flight stage, where the main rotor system is turned by relative wind rather than engine power.
c)
happens when it is hovering above the ground.
d)
In a steady-state flight, the helicopter has a load factor of ____, which means the main rotor system supports the helicopter 's actual total weight.
42.
increases to two
a)
TRUE
b)
If you raise the bank angle to 60 ° while holding a steady altitude, the load factor _________________.
c)
In translational lift, the increased flow is most apparent when the airspeed approaches _________ or so.
d)
- the downward force of the air.
43.
Load factor
a)
the ratio of the load supported by the main rotor system to the actual weight of the helicopter and its contents.
b)
done on asymmetrical airfoils wherein the trailing edge is bended to create the same features as symmetrical airfoils.
c)
When you bank a helicopter while maintaining a constant altitude, the "G" load or load factor __________.
d)
An imaginary straight line from the leading edge to the trailing edge of an airfoil.
44.
Disc loading
a)
In translational lift, the increased flow is most apparent when the airspeed approaches _________ or so.
b)
the weight ratio to the total main rotor disk area, which is measured by dividing the total helicopter weight by the rotor disk area, which is the area swept by a rotor blades.
c)
the difference in lift that exists between the advancing half of the rotor disk and the retreating half.
d)
gives the rotor blade an equivalent amount of pitch no matter where it is in the plane of rotation (rotor disc) and is used to adjust the thrust of the rotor.
45.
power
a)
an upward sweeping angle of the rotor blades as a result of lift and centrifugal force.
b)
occurs as the rotor blades begin to lift the weight of the helicopter.
c)
As disc loading increases, greater the ________ you need to control the speed of the rotor.
d)
The helicopter fuselage turns ______ as the engine turns the main rotor system in a counterclockwise direction.
46.
Solidity ratio
a)
ratio of the total rotor blade area to the total rotor disk area, which is the total area of all the main rotor blades.
b)
the difference in lift that exists between the advancing half of the rotor disk and the retreating half.
c)
the ratio of the load supported by the main rotor system to the actual weight of the helicopter and its contents.
d)
The lift and thrust generated by the rotor system act straight up for a helicopter to _____ and must be equal to the weight and drag that act straight down.
47.
Solidity ratio
a)
done on asymmetrical airfoils wherein the trailing edge is bended to create the same features as symmetrical airfoils.
b)
the curvature of the airfoil's upper and lower surfaces.
c)
TRUE or FALSE
d)
This ratio provides a way of calculating a rotor system's ability to produce thrust.
48.
Powered Flight
a)
done on asymmetrical airfoils wherein the trailing edge is bended to create the same features as symmetrical airfoils.
b)
The direction of this wind is relative to the attitude, or position, of the airfoil and is always parallel, equal, and opposite in direction to the flight path.
c)
these are used to prevent the blades from hitting the fuselage when starting up or shutting down.
d)
rotor 's total lifting and thrust forces are perpendicular to the rotor 's tip-path plane or plane of rotation of the rotor.
49.
hovering flight
a)
A helicopter holds a constant location over a selected point during a _____________, normally only a few feet above ground.
b)
happens when it is hovering above the ground.
c)
A single main rotor helicopter, during the hovering flight, appears to drift in the same direction as the thrust of antitorque rotor. This drifting tendency is called ______________________.
d)
When tip-path plane to tilt to the rear.
50.
hover
a)
The lift and thrust generated by the rotor system act straight up for a helicopter to _____ and must be equal to the weight and drag that act straight down.
b)
used to control the yaw of the helicopter.
c)
upward force created by the effect of airflow as it passes around an airfoil.
d)
Two-bladed rotor systems are usually subject to Coriolis Effect to a much lower degree than articulated rotor systems because the blades are typically "__________" with respect to the rotor hub, and the shift in the center of mass distance from the rotation axis is minimal.
51.
Translating tendency
a)
the movement of the helicopter to the right due to the combination of main rotor torque and tail-rotor anti-torque.
b)
happens when it is hovering above the ground.
c)
In a steady-state flight, the helicopter has a load factor of ____, which means the main rotor system supports the helicopter 's actual total weight.
d)
Since the fuselage of the helicopter, with a single main rotor, is suspended from a single point and has considerable mass, it is free to oscillate either longitudinally or laterally in the same way as a pendulum.
52.
translating tendency
a)
It is caused by the fact that in directional flight the aircraft relative wind is added to the rotational relative wind on the advancing blade and subtracted on the retreating blade.
b)
A single main rotor helicopter, during the hovering flight, appears to drift in the same direction as the thrust of antitorque rotor. This drifting tendency is called ______________________.
c)
opposes lift and is caused by the downward pull of gravity.
d)
TRUE or FALSE
53.
Pendular Action
a)
This ratio provides a way of calculating a rotor system's ability to produce thrust.
b)
these are used to prevent the blades from hitting the fuselage when starting up or shutting down.
c)
a significant consequence of thrust production.
d)
Since the fuselage of the helicopter, with a single main rotor, is suspended from a single point and has considerable mass, it is free to oscillate either longitudinally or laterally in the same way as a pendulum.
54.
Coning
a)
accomplished by increasing the pitch angle of the main rotor blades.
b)
the first part of the airfoil to meet the oncoming air.
c)
occurs as the rotor blades begin to lift the weight of the helicopter.
d)
an upward sweeping angle of the rotor blades as a result of lift and centrifugal force.
55.
Rotor blade coning
a)
provides aerodynamic force when it interacts with a moving stream of air.
b)
The imaginary line about which the rotor rotates. It is represented by a line drawn through the center of, and perpendicular to, the tip-path plane.
c)
The production of _____ is based upon the airfoil creating circulation in the airstream (Magnus Effect) and creating differential pressure on the airfoil (Bernoulli's Principle).
d)
occurs as the rotor blades begin to lift the weight of the helicopter.
56.
Coriolis Effect (Law of Conservation of Angular Momentum)
a)
In fluid dynamics, the momentum theory or disk actuator theory is a theory describing a mathematical model of an ideal actuator disk, such as a propeller or helicopter rotor, by _________ , _______ and _________.
b)
when the rotor blades speed up or slow down as the center of gravity moves closer or further away from the axis of rotation.
c)
a condition when an aircraft is in straight-and-level, unaccelerated flight, and all forces are in balance.
d)
provides aerodynamic force when it interacts with a moving stream of air.
57.
underslung
a)
- the downward force of the air.
b)
TRUE
c)
Two-bladed rotor systems are usually subject to Coriolis Effect to a much lower degree than articulated rotor systems because the blades are typically "__________" with respect to the rotor hub, and the shift in the center of mass distance from the rotation axis is minimal.
d)
As the induced flow increases, the angle of attack _________.
58.
Teetering
a)
_________ is used to mitigate the Coriolis effect.
b)
the resulting movement or deflection of a rotating object when a force on this object is applied.
c)
the ratio of the load supported by the main rotor system to the actual weight of the helicopter and its contents.
d)
The direction of this wind is relative to the attitude, or position, of the airfoil and is always parallel, equal, and opposite in direction to the flight path.
59.
Ground Effect
a)
the first part of the airfoil to meet the oncoming air.
b)
happens when it is hovering above the ground.
c)
TRUE
d)
the movement of the helicopter to the right due to the combination of main rotor torque and tail-rotor anti-torque.
60.
Ground Effect
a)
Since the fuselage of the helicopter, with a single main rotor, is suspended from a single point and has considerable mass, it is free to oscillate either longitudinally or laterally in the same way as a pendulum.
b)
As the rotor blades rotate, they generate what is called __________.
c)
this effect occurs less than one diameter of rotor above the surface.
d)
provides aerodynamic force when it interacts with a moving stream of air.
61.
maximum
a)
a significant consequence of thrust production.
b)
In a no-wind condition over a solid, smooth surface the ground effect is at its ____________.
c)
A helicopter holds a constant location over a selected point during a _____________, normally only a few feet above ground.
d)
theory describing a mathematical model of an ideal actuator disk, such as a propeller or helicopter rotor.
62.
Gyroscopic Precession
a)
refers to a principle of gyroscopes that states when a force is applied to a spinning object, the maximum reaction occurs approximately 90 degrees later in the direction of rotation.
b)
done on asymmetrical airfoils wherein the trailing edge is bended to create the same features as symmetrical airfoils.
c)
opposes lift and is caused by the downward pull of gravity.
d)
The imaginary line about which the rotor rotates. It is represented by a line drawn through the center of, and perpendicular to, the tip-path plane.
63.
Gyroscopic Precession
a)
The direction of the relative wind is relative to the attitude, or position, of the airfoil and is always parallel, equal, and opposite in direction to the ___________.
b)
aft portion where the airflow over the upper surface joins the airflow under the lower surface.
c)
the resulting movement or deflection of a rotating object when a force on this object is applied.
d)
When a helicopter is at rest, the blades will droop because of a lack of _______________.
64.
Translational Lift
a)
b)
wind moving past the airfoil.
c)
the curvature of the airfoil's upper and lower surfaces.
d)
where the efficiency of the hovering rotor system is improved with each knot of incoming wind gained by horizontal movement or surface wind.
65.
16 to 24 knots
a)
TRUE or FALSE
b)
aft portion where the airflow over the upper surface joins the airflow under the lower surface.
c)
In translational lift, the increased flow is most apparent when the airspeed approaches _________ or so.
d)
where the efficiency of the hovering rotor system is improved with each knot of incoming wind gained by horizontal movement or surface wind.
66.
pitches up; right
a)
The direction of this wind is relative to the attitude, or position, of the airfoil and is always parallel, equal, and opposite in direction to the flight path.
b)
where the efficiency of the hovering rotor system is improved with each knot of incoming wind gained by horizontal movement or surface wind.
c)
In fluid dynamics, the momentum theory or disk actuator theory is a theory describing a mathematical model of an ideal actuator disk, such as a propeller or helicopter rotor, by _________ , _______ and _________.
d)
In translational lift, if no corrections are made, the nose _______, and rolls to the _______.
67.
TRUE
a)
In translational lift, if no corrections are made, the nose _______, and rolls to the _______.
b)
the ratio of the load supported by the main rotor system to the actual weight of the helicopter and its contents.
c)
aft portion where the airflow over the upper surface joins the airflow under the lower surface.
d)
TRUE
68.
a)
done on asymmetrical airfoils wherein the trailing edge is bended to create the same features as symmetrical airfoils.
b)
a significant consequence of thrust production.
c)
when the rotor blades speed up or slow down as the center of gravity moves closer or further away from the axis of rotation.
d)
69.
if the wind speed is approximately 16 to 24 knots.
a)
rotor 's total lifting and thrust forces are perpendicular to the rotor 's tip-path plane or plane of rotation of the rotor.
b)
The production of _____ is based upon the airfoil creating circulation in the airstream (Magnus Effect) and creating differential pressure on the airfoil (Bernoulli's Principle).
c)
When tip-path plane to tilt to the rear.
d)
TRUE or FALSE
70.
a)
TRUE
b)
The helicopter fuselage turns ______ as the engine turns the main rotor system in a counterclockwise direction.
c)
d)
In a steady-state flight, the helicopter has a load factor of ____, which means the main rotor system supports the helicopter 's actual total weight.
71.
Translational lift is also present in a stationary hover.
a)
Translational lift is also present in a stationary hover.
b)
Two-bladed rotor systems are usually subject to Coriolis Effect to a much lower degree than articulated rotor systems because the blades are typically "__________" with respect to the rotor hub, and the shift in the center of mass distance from the rotation axis is minimal.
c)
In fluid dynamics, the momentum theory or disk actuator theory is a theory describing a mathematical model of an ideal actuator disk, such as a propeller or helicopter rotor, by _________ , _______ and _________.
d)
ratio of the total rotor blade area to the total rotor disk area, which is the total area of all the main rotor blades.
72.
rotational relative wind
a)
As the rotor blades rotate, they generate what is called __________.
b)
happens when it is hovering above the ground.
c)
If you raise the bank angle to 60 ° while holding a steady altitude, the load factor _________________.
d)
shifts the pitch of each blade as a function of where it is in the plane of rotation.
73.
Induced Flow
a)
opposes lift and is caused by the downward pull of gravity.
b)
is defined as flowing parallel, opposite the axis of rotation of the rotor and distinctly perpendicular to the leading edge of the rotor blade.
c)
theory describing a mathematical model of an ideal actuator disk, such as a propeller or helicopter rotor.
d)
Translational lift is also present in a stationary hover.
74.
Induced Flow
a)
where the efficiency of the hovering rotor system is improved with each knot of incoming wind gained by horizontal movement or surface wind.
b)
Two-bladed rotor systems are usually subject to Coriolis Effect to a much lower degree than articulated rotor systems because the blades are typically "__________" with respect to the rotor hub, and the shift in the center of mass distance from the rotation axis is minimal.
c)
phenomenon affecting the rotor of a helicopter as it overcomes dissymmetry of lift through flapping
d)
- has an effect on the AOA.
75.
- the downward force of the air.
a)
used to control the yaw of the helicopter.
b)
As disc loading increases, greater the ________ you need to control the speed of the rotor.
c)
A single main rotor helicopter, during the hovering flight, appears to drift in the same direction as the thrust of antitorque rotor. This drifting tendency is called ______________________.
d)
- the downward force of the air.
76.
Decreases
a)
The helicopter fuselage turns ______ as the engine turns the main rotor system in a counterclockwise direction.
b)
c)
Decreases
d)
When a helicopter is at rest, the blades will ________ because of a lack of centrifugal stiffening.
77.
a)
the weight ratio to the total main rotor disk area, which is measured by dividing the total helicopter weight by the rotor disk area, which is the area swept by a rotor blades.
b)
c)
the curvature of the airfoil's upper and lower surfaces.
d)
the difference in lift that exists between the advancing half of the rotor disk and the retreating half.
78.
and therefore, also decreases the amount of lift produced.
a)
As the induced flow increases, the angle of attack _________.
b)
can be recognized because of increased vibrations of the helicopter at airspeeds just below effective translational lift on takeoff and after passing through effective translational lift during landing.
c)
This ratio provides a way of calculating a rotor system's ability to produce thrust.
d)
The resultant of _________ determines the direction of movement of the helicopter.
79.
Transverse Flow Effect
a)
refers to a changing chord line from the blade root to the tip.
b)
upward force created by the effect of airflow as it passes around an airfoil.
c)
can be recognized because of increased vibrations of the helicopter at airspeeds just below effective translational lift on takeoff and after passing through effective translational lift during landing.
d)
meaning both the upper and the lower surfaces had the same camber (curvature)
80.
Transverse Flow Effect
a)
refers to a changing chord line from the blade root to the tip.
b)
The result of this effect is a tendency for the helicopter to roll slightly to the right as it accelerates through approximately 20 knots or if the headwind is approximately 20 knots.
c)
wind moving past the airfoil.
d)
the ratio of the load supported by the main rotor system to the actual weight of the helicopter and its contents.
81.
Dissymmetry of Lift
a)
occurs as the rotor blades begin to lift the weight of the helicopter.
b)
the difference in lift that exists between the advancing half of the rotor disk and the retreating half.
c)
A single main rotor helicopter, during the hovering flight, appears to drift in the same direction as the thrust of antitorque rotor. This drifting tendency is called ______________________.
d)
As the rotor blades rotate, they generate what is called __________.
82.
Dissymmetry of Lift
a)
opposes lift and is caused by the downward pull of gravity.
b)
retarding force created by development of lift and the movement of an object through the air
c)
occurs as the rotor blades begin to lift the weight of the helicopter.
d)
It is caused by the fact that in directional flight the aircraft relative wind is added to the rotational relative wind on the advancing blade and subtracted on the retreating blade.
83.
blowback
a)
these are used to prevent the blades from hitting the fuselage when starting up or shutting down.
b)
The lift and thrust generated by the rotor system act straight up for a helicopter to _____ and must be equal to the weight and drag that act straight down.
c)
often caused by the induced drag experienced when the blades generate lift.
d)
When tip-path plane to tilt to the rear.
84.
Flap back or blowback
a)
utilized to restrict excessive blade sailing when starting the helicopter up in a wind.
b)
Translational lift is also present in a stationary hover.
c)
phenomenon affecting the rotor of a helicopter as it overcomes dissymmetry of lift through flapping
d)
often caused by the induced drag experienced when the blades generate lift.
85.
Autorotation
a)
When tip-path plane to tilt to the rear.
b)
rotor 's total lifting and thrust forces are perpendicular to the rotor 's tip-path plane or plane of rotation of the rotor.
c)
In a no-wind condition over a solid, smooth surface the ground effect is at its ____________.
d)
is the flight stage, where the main rotor system is turned by relative wind rather than engine power.
86.
Retreating Blade Stall
a)
In a steady-state flight, the helicopter has a load factor of ____, which means the main rotor system supports the helicopter 's actual total weight.
b)
refers to a principle of gyroscopes that states when a force is applied to a spinning object, the maximum reaction occurs approximately 90 degrees later in the direction of rotation.
c)
wind moving past the airfoil.
d)
Stall due to too high AOA.
87.
momentum theory or disk actuator theory
a)
phenomenon affecting the rotor of a helicopter as it overcomes dissymmetry of lift through flapping
b)
the weight ratio to the total main rotor disk area, which is measured by dividing the total helicopter weight by the rotor disk area, which is the area swept by a rotor blades.
c)
theory describing a mathematical model of an ideal actuator disk, such as a propeller or helicopter rotor.
d)
In translational lift, if no corrections are made, the nose _______, and rolls to the _______.
88.
W.J.M. Rankine, Alfred George Greenhill, Robert Edmund Froude
a)
refers to a changing chord line from the blade root to the tip.
b)
refers to a principle of gyroscopes that states when a force is applied to a spinning object, the maximum reaction occurs approximately 90 degrees later in the direction of rotation.
c)
In fluid dynamics, the momentum theory or disk actuator theory is a theory describing a mathematical model of an ideal actuator disk, such as a propeller or helicopter rotor, by _________ , _______ and _________.
d)
Decreases
100 %
