Army Aviation Information
A pilot controls a helicopter using - ANSWER: Pedals and a collective, throttle and
cyclic
From a physics prospective, the ____ force is deemed to act through a helicopter ___ -
ANSWER: total weight; center of gravity
Newton's third law of motion applies to helicopters because ____ - ANSWER: The
spinning main rotor makes the aircraft try to spin in the opposite direction
What happens when a helicopter's main rotor blades spin rapidly? - ANSWER: The
upper and lower sides of each blade experience a difference in pressure
When the pilot pushes the cyclic forward ____ - ANSWER: The main rotor disk tilts
forward
Which of the following factors affect the lift produced by spinning rotor blades? -
ANSWER: Airfoil coefficient of lift, air density, and blade area (ALL OF THE ABOVE)
A helicopter's potential energy is affected by ____ - ANSWER: The aircraft height above
the ground
When plotted on a graph, L/DMax is the point where the helicopter's ___ - ANSWER:
Total lift_to_drag ratio is the greatest
Vortices produced by spinning rotor blades create ___ - ANSWER: Induced Drag
What is induced drag? - ANSWER: The drag created as a result of lift-off; vorticies
produced by spinning rotor blades
What is profile drag? - ANSWER: The drag incurred from frictional resistance of the
blades passing through the airfoil section, but increasing moderately as air speed
increases
Profile drag consists of ___ created by ___ and ___ - ANSWER: Frictional resistance;
the airfoil section; increased speed
Thrust acts ___ to the aircraft's ___ - ANSWER: Parallel; longitudinal axis
In the case of helicopter lift, it is produced by ___ moving through the air at the speed
sufficient to create ___ - ANSWER: airfoils; a pressure differential
, When a pilot banks a helicopter, causing it to turn, what happens to the weight? -
ANSWER: It increases
Multi-engine helicopters have ___ - ANSWER: A throttle lever for each engine
When the pilot wants the helicopter's nose to move left or right, he or she ___ -
ANSWER: Pushes the corresponding pedal
For helicopter's with a main rotor disk that spins counter-clockwise the ___ airflow
speed happens when each blade reaches the ___ position - ANSWER: Maximum; three
o'clock(right)
On the advancing rotor blade, lift ___ and the blade ___ - ANSWER: increases; moves
upward
The angle between the ___ of a rotor blade and it's direction of motion relative to the
___ is the angle of attack (AOA) which is ___ Angle - ANSWER: Chord line; air; an
aerodynamic
The angle of incidence is between the ___ line of each blade and the rotor system's ___
- ANSWER: Chord; plane of rotation
When a helicopter engine ___, a clutch mechanism called a ___ - ANSWER: fails;
freewheeling unit automatically disconnects the engine from the main rotor, allowing it to
spin freely.
During an auto-rotation in forward flight, the rotor disk takes in ___ air and the driven,
driving, and stall regions of each blade move ___ along it's length (span) but only on the
___ side of the disk. - ANSWER: upward flowing, outboard, retreating
Where there is too much lift, the main rotor blades will ___ - ANSWER: Flap
Helicopter turbine engines produce ___ thrust per pound than piston engines -
ANSWER: more
A helicopter is___ - ANSWER: A type of rotorcraft
The phenomenon of a helicopter sinking into its own downwash is called ___ -
ANSWER: Settling with power
Wheels on ___ types of helicopters are ___ - ANSWER: some; retractable
Helicopters experience effective translation lift while transitioning to forward flight at
approximately ___ to ___ knots - ANSWER: 16; 24
A pilot controls a helicopter using - ANSWER: Pedals and a collective, throttle and
cyclic
From a physics prospective, the ____ force is deemed to act through a helicopter ___ -
ANSWER: total weight; center of gravity
Newton's third law of motion applies to helicopters because ____ - ANSWER: The
spinning main rotor makes the aircraft try to spin in the opposite direction
What happens when a helicopter's main rotor blades spin rapidly? - ANSWER: The
upper and lower sides of each blade experience a difference in pressure
When the pilot pushes the cyclic forward ____ - ANSWER: The main rotor disk tilts
forward
Which of the following factors affect the lift produced by spinning rotor blades? -
ANSWER: Airfoil coefficient of lift, air density, and blade area (ALL OF THE ABOVE)
A helicopter's potential energy is affected by ____ - ANSWER: The aircraft height above
the ground
When plotted on a graph, L/DMax is the point where the helicopter's ___ - ANSWER:
Total lift_to_drag ratio is the greatest
Vortices produced by spinning rotor blades create ___ - ANSWER: Induced Drag
What is induced drag? - ANSWER: The drag created as a result of lift-off; vorticies
produced by spinning rotor blades
What is profile drag? - ANSWER: The drag incurred from frictional resistance of the
blades passing through the airfoil section, but increasing moderately as air speed
increases
Profile drag consists of ___ created by ___ and ___ - ANSWER: Frictional resistance;
the airfoil section; increased speed
Thrust acts ___ to the aircraft's ___ - ANSWER: Parallel; longitudinal axis
In the case of helicopter lift, it is produced by ___ moving through the air at the speed
sufficient to create ___ - ANSWER: airfoils; a pressure differential
, When a pilot banks a helicopter, causing it to turn, what happens to the weight? -
ANSWER: It increases
Multi-engine helicopters have ___ - ANSWER: A throttle lever for each engine
When the pilot wants the helicopter's nose to move left or right, he or she ___ -
ANSWER: Pushes the corresponding pedal
For helicopter's with a main rotor disk that spins counter-clockwise the ___ airflow
speed happens when each blade reaches the ___ position - ANSWER: Maximum; three
o'clock(right)
On the advancing rotor blade, lift ___ and the blade ___ - ANSWER: increases; moves
upward
The angle between the ___ of a rotor blade and it's direction of motion relative to the
___ is the angle of attack (AOA) which is ___ Angle - ANSWER: Chord line; air; an
aerodynamic
The angle of incidence is between the ___ line of each blade and the rotor system's ___
- ANSWER: Chord; plane of rotation
When a helicopter engine ___, a clutch mechanism called a ___ - ANSWER: fails;
freewheeling unit automatically disconnects the engine from the main rotor, allowing it to
spin freely.
During an auto-rotation in forward flight, the rotor disk takes in ___ air and the driven,
driving, and stall regions of each blade move ___ along it's length (span) but only on the
___ side of the disk. - ANSWER: upward flowing, outboard, retreating
Where there is too much lift, the main rotor blades will ___ - ANSWER: Flap
Helicopter turbine engines produce ___ thrust per pound than piston engines -
ANSWER: more
A helicopter is___ - ANSWER: A type of rotorcraft
The phenomenon of a helicopter sinking into its own downwash is called ___ -
ANSWER: Settling with power
Wheels on ___ types of helicopters are ___ - ANSWER: some; retractable
Helicopters experience effective translation lift while transitioning to forward flight at
approximately ___ to ___ knots - ANSWER: 16; 24
