SIFT Study Guide Army Aviation Information Practice Test

Question 1

A helicopter is

Answer 1

A type of rotorcraft

Question 2

Helicopter turbine engines produce ______ thrust per pound than piston engines:

Answer 2

More

Question 3

The main forces acting on a helicopter are

Answer 3

Lift, weight, thrust, drag

Question 4

Helicopters typically have between __ and __ main rotor blade(s):

Answer 4

2,6

Question 5

Depending on the type of helicopter, main rotor system components can include:

Answer 5

A stabilizer bar, upper and lower swashplates, counterweights, pitch horns, teeter or coning hinges, blad grips, pitch and scissor links, and control rods

Question 6

The function of the flybar is

Answer 6

To decrease crosswind thrust on the blades and enhance flight stability by keeping the bar stable as the rotor spins

Question 7

Many helicopters have a horizontal stabilizer located

Answer 7

On the tail boom

Question 8

The purpose of the tail rotor is

Answer 8

To produce an anti-torque force acting perpendicular to the helicopter’s longitudinal axis

Question 9

Wheels on ____ types of helicopters are _____

Answer 9

some, retractable

Question 10

A pilot controls a helicopter using

Answer 10

Pedals, a collective, throttle, and cyclic

Question 11

From a physics perspective, the ____ force is deemed to act through a helicopter’s _____

Answer 11

total weight, center of gravity

Question 12

When a pilot banks a helicopter, causing it to turn, _________

Answer 12

The machine’s weight increases

Question 13

In the case of helicopters, lift is produced by _______ moving through the air at a speed sufficient to create ________

Answer 13

airfoils, a pressure differential

Question 14

Thrust acts ____ to the aircraft’s ____

Answer 14

parallel, longitudinal axis

Question 15

Profile drag consists of _____ created by ______ and ______

Answer 15

skin friction, surface imperfections, form drag

Question 16

Vortices produced by spinning rotor blades create

Answer 16

Induced drag

Question 17

When plotted on a graph, L/DMAX is the point where the helicopter’s

Answer 17

Total lift-to-drag ratio is the greatest

Question 18

A helicopter’s potential energy is affected by

Answer 18

The aircraft’s height above the ground

Question 19

Which of the following factors affect the lift produced by spinning rotor blades?

Answer 19

Airfoil coefficient of lift, air density, and blade area

Question 20

What happens when a helicopter’s main rotor blades spin rapidly?

Answer 20

The upper and lower sides of each blade experience a difference in pressure

Question 21

Newton’s Third Law of Motion applies to helicopters because

Answer 21

The spinning main rotor makes the aircraft try to spin in the opposite direciton

Question 22

When the pilot pushes the cyclic forward

Answer 22

The main rotor disk tilts forward

Question 23

Multi-engine helicopters have

Answer 23

a throttle lever for each engine

Question 24

When the pilot wants the helicopter’s nose to move left or right, he

Answer 24

Pushes on the corresponding pedal

Question 25

For helicopters with a main rotor disk that spins counter-clockwise, the ___ airflow speed happens when each blade reaches the ___ position

Answer 25

maximum, three o'clock (right)

Question 26

On the advancing rotor blade, lift ___ and the blade _____

Answer 26

increases, moves upward

Question 27

The angle between the ____ of a rotor blade and its direction of motion relative to the _____ is the angle of attack (AOA), which is _____ angle

Answer 27

Chord line, air, an aerodynamic

Question 28

The angle of incidence is between the ____ line of each blade and the rotor system's ____

Answer 28

chord, plane of rotation

Question 29

When a helicopter engine ____, a clutch mechanism called a __________________

Answer 29

fails, free wheeling unit automatically disconnects the engine from the main rotor, allowing it to spin freely

Question 30

During an autorotation in forward flight, the rotor disk takes in ____ air and the driven, driving, and stall regions of each blade move _______ along its length (span), but only on the ______ side of the disk

Answer 30

upward flowing, outboard, retreating

Question 31

Where there is too much lift, the main rotor blades will

Answer 31

Flap

Question 32

Centrifugal force _____ spinning helicopter main rotor blades _______.

Answer 32

pulls, outward

Question 33

If left uncorrected, greater lift produced by the advancing side of the rotor disk compared to the lift created by the disk's retreating side could make the helicopter ______.

Answer 33

uncontrollable

Question 34

The driven region is _____ the blade tips and normally ____ percent of the radius.

Answer 34

nearest, 30

Question 35

The _____ region is normally between a blade's _____ and _____ regions.

Answer 35

driving, stall, driven

Question 36

Because of gyroscopic precession, if a wind gust applies a downward force on the left side of a helicopter's main rotor disk as it spins clockwise (as viewed from above), the movement response occurs at the __ o'clock position.

Answer 36

12

Question 37

Helicopters experience effective translational lift while transitioning to forward flight at approximately __ to __ knots

Answer 37

16, 24

Question 38

Maximum ground effect occurs during a hover up to a heigh equal to __ percent of the main rotor's diameter

Answer 38

100

Question 39

A pilot can worsen a helicopter's pendular action by

Answer 39

Over-controlling the aircraft

Question 40

The phenomenon of a helicopter sinking into its own downwash is called

Answer 40

Settling with power