ROTOR SYSTEMS

Question 1

Main Rotor System type and subsystems

Answer 1

fully articulated main rotor system

main rotor blades, hub, flight controls, and the bifilar vibration absorber

Question 2

The elastomeric bearings per blade enable:

Answer 2

1. blades to flap, lead, and lag
2. permit the blade to move about its axis for pitch changes

Question 3

Main rotor dampers purpose:

Answer 3

restrain lead and lag motions of the main rotor blades during rotation and absorb rotor head starting loads

supplied with nitrogen-pressurized hydraulic fluid
from a reservoir mounted inside the main rotor shaft

The 1-gallon reservoir, located in the main rotor mast, is shared between all dampers and has indicators to monitor the fluid level and nitrogen pressure

Question 4

Swashplate purpose:

Answer 4

It transmits flight control movement to the main rotor through four pitch control rods

Question 5

The droop stops and flap restraints prevent:

Answer 5

extremely high or low blade flapping at low Nr

Question 6

Antiflap restraints go out at:

Answer 6

When the main rotor is
at 35 percent Nr or greater, centrifugal force pulls the antiflapping restraints outward and holds them in position to permit flapping and coning of the blades

Question 7

As rotor speed increases, the droop stops:

Answer 7

rotate from their static
position to a dynamic position, allowing full blade flapping action. Centrifugal force pulls the droop stops out at approximately 70 percent Nr and permits increased vertical movement of the blade.

Question 8

On shutdown, droop stops:

Answer 8

will seat at approximately 50 percent Nr

Question 9

Blade build and composition

Answer 9

pressurized hollow spar,
honeycomb core, outer skin, abrasion strips, electrothermal deicing mats, and a removable swept-back blade tip
fairing

Question 10

Blade sweep angle and purpose

Answer 10

20° swept tips provide both sound attenuation and increased rotor blade efficiency

Question 11

Blade de ice provided by what blade component?

Answer 11

electrothermal
blanket is bonded into the leading edge

Question 12

Abrasion strips provide what?

Answer 12

extend the useful life of the blades

Question 13

The spar of the main rotor blade is pressurized with?

Answer 13

nitrogen

If the blade is damaged and the structural integrity of the spar is impaired, nitrogen will escape and cause the Blade Inspection
Method (BIM®) pressure indicator to show a black, or unsafe, indication

Question 14

Tail Rotor System:

Answer 14

bearingless, crossbeam tail rotor blade system

Question 15

Tail rotor blade flap and pitch-change motions result from:

Answer 15

deflection of the flexible spar

Question 16

TR cant and lifting force

Answer 16

canted 20° upward, and provide 2.5 percent of the total lifting force in a hover

Question 17

Dual TR control cable spring for tension airspeed window

Answer 17

25 and 145 Knots Indicated Airspeed

Question 18

The tail rotor indexing system does these two things:

Answer 18

1. positions the tail rotor blades during pylon fold operations
2. prevents the tail rotor from windmilling in winds up to 60 knots

Question 19

Do TR blades have abrasion strips and deicing?

Answer 19

Yes and Yes

electrothermal
blankets for deicing

Question 20

Whenever locking or unlocking the gust lock, the GUST LOCK switch shall be held in the LKD or UNLK position
for a minimum of…

Answer 20

5 seconds

Question 21

AVCS system consists of…

Answer 21

AVC Computer (AVCC)
10 feedback accelerometers
Vibration Control Actuation System (VCAS)

Question 22

The VCAS is comprised of…

Answer 22

1 VCAS Electronics Unit (EU)
4 Force Generators (FGs)

Question 23

AVCS injects a ___ per vibratory force

Answer 23

4

Question 24

AVCS utilizes a ___ ___ feedback control algorithm

Answer 24

closed loop

Question 25

AVCS utilizes ____ as feedback sensors and ____ as a reference signal to swiftly and accurately track changes in rotor speed

Answer 25

accelerometers
tachometer (Nr sensor)

Question 26

AVCS ground vibration-nulling solution on a ____ cycle

Answer 26

300-second (5 minute)