Rotor System

Question 1

What type of rotor system do we have?

Answer 1

Fully articulated

Question 2

How are the main rotor blades attached?

Answer 2

Attach to hinged spindles and retained by elastomeric bearings

Question 3

What is the purpose of elastomeric bearings?

Answer 3

Allow blade to lead, lag, and flap and permit blade to move about its axis for pitch change

Question 4

What are the subsystems of the main rotor?

Answer 4

Blades
Hub
Flight Control
Bifilar Vibration Absorber

Question 5

What do the blade dampers provide?

Answer 5

Restrain lead/lag and absorb rotor head starting loads

Question 6

Where is the blade damper reservoir and how is it pressurized?

Answer 6

Reservoir is located in the main rotor shaft

Each damper is supplied with nitrogen pressurized HYD fluid

Question 7

What does the low pressure plate provide?

Answer 7

Provides attachment to the swashplate

Question 8

How are flight control inputs transmitted to the main rotor blades?

Answer 8

Inputs from flight controls routed to the swashplate then to the PCRs to the pitch change horns

Question 9

What do droop stops and flap restraints provide?

Answer 9

Prevent extreme high/low blade flap at low Nr

Question 10

When do flap restraints pull out?

Answer 10

~ 35% Nr

Question 11

When do droop stops pull out?

Answer 11

~ 70% Nr

Question 12

When do droop stops seat?

Answer 12

~ 50% Nr

Question 13

What is the composition of the main rotor blades?

Answer 13

Pressurized hollow spar
Honeycomb core
Outer skin
Abrasion strips - extend blade life
De-Ice mats
20 degree swept back Blade Tips

Question 14

What do the blade tips provide?

Answer 14

Sound attenuation and increased rotor efficiency

Question 15

How are the blades pressurized?

Answer 15

Nitrogen and include Blade Inspection Method(BIM) to show damage (black) indication

Question 16

How are the blades connected to the spindle?

Answer 16

Bolted flange

Question 17

What does the Tail Rotor provide?

Answer 17

Anti-TRQ and directional control

Question 18

How does the T/R provide control?

Answer 18

The flap and pitch changes come from the deflection of the flexible spar

Question 19

What is the cant and total lift provided by the T/R?

Answer 19

20 degree upward cant and provide 2.5% total lift in a hover

Question 20

What is happening in the T/R Quadrant when both cables are lost?

Answer 20

Spring tension feature provides a positive pitch on T/R equal to that of a mid-position collective setting

Question 21

What does the T/R index system do?

Answer 21

Positions T/R blades during fold and prevents windmilling in winds up to 60 KIAS when folded

Question 22

What does the T/R Quadrant provide?

Answer 22

Transmits all cable movements into the T/R servo

Question 23

What happens if 1 T/R cable is broken?

Answer 23

Operates normally by controlling the other cable against spring tension and TAIL ROTOR QUADRANT caution illuminates from respective microswitch

Question 24

How does the T/R Head work?

Answer 24

Consist of 2 plates. Inboard plate forms hub with the output shaft.

Hub plates absorb axial trust loads and bending moment and transmit TRQ to the blades.

Blade spars clamped together and the pitch change crossbeam is attached to the output shaft to provide pitch changes

Question 25

How many T/R spars are there?

Answer 25

2 interchangeable spars that cross at the center to form 4 blades