ROTOR SYSTEMS Flashcards

1
Q

Main Rotor System type and subsystems

A

fully articulated main rotor system

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

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2
Q

The elastomeric bearings per blade enable:

A
  1. blades to flap, lead, and lag
  2. permit the blade to move about its axis for pitch changes
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3
Q

Main rotor dampers purpose:

A

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

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4
Q

Swashplate purpose:

A

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

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5
Q

The droop stops and flap restraints prevent:

A

extremely high or low blade flapping at low Nr

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6
Q

Antiflap restraints go out at:

A

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

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7
Q

As rotor speed increases, the droop stops:

A

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.

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8
Q

On shutdown, droop stops:

A

will seat at approximately 50 percent Nr

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9
Q

Blade build and composition

A

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

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10
Q

Blade sweep angle and purpose

A

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

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11
Q

Blade de ice provided by what blade component?

A

electrothermal
blanket is bonded into the leading edge

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12
Q

Abrasion strips provide what?

A

extend the useful life of the blades

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13
Q

The spar of the main rotor blade is pressurized with?

A

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

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14
Q

Tail Rotor System:

A

bearingless, crossbeam tail rotor blade system

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15
Q

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

A

deflection of the flexible spar

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16
Q

TR cant and lifting force

A

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

17
Q

Dual TR control cable spring for tension airspeed window

A

25 and 145 Knots Indicated Airspeed

18
Q

The tail rotor indexing system does these two things:

A
  1. positions the tail rotor blades during pylon fold operations
  2. prevents the tail rotor from windmilling in winds up to 60 knots
19
Q

Do TR blades have abrasion strips and deicing?

A

Yes and Yes

electrothermal
blankets for deicing

20
Q

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

A

5 seconds

21
Q

AVCS system consists of…

A

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

22
Q

The VCAS is comprised of…

A

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

23
Q

AVCS injects a ___ per vibratory force

A

4

24
Q

AVCS utilizes a ___ ___ feedback control algorithm

A

closed loop

25
Q

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

A

accelerometers
tachometer (Nr sensor)

26
Q

AVCS ground vibration-nulling solution on a ____ cycle

A

300-second (5 minute)