NATOPS CH2.2 Rotor System Flashcards
What is the purpose of the Elastomeric Bearings?
They enable the blades to flap, lead, lag, and also move about its axis for pitch changes.
What do the Main Rotor Dampers do?
Where do they get their pressure from and how much should they be pressurized?
They restrain the lead and lag motions of the main rotor blades during rotation and absorb rotor head starting loads.
Each damper is supplied with nitrogen-pressurized hydraulic fluid from a reservoir mounted inside the main rotor shaft. During preflight the reservoir needs to be at least 1200psi, and indicating in the green or yellow range.
How are control inputs transmitted to the blades from the swashplates up?
Stationary swashplate -> Rotating Swashplate -> Pitch Change Control Rods -> Pitch Change Horn -> Blades
The swashplates rotates and slides on a teflon-coated uniball.
What do the droop stops / flap restraints do, and when are they engaged/disengaged?
They prevent extremely high or low blade flapping at low Nr
At 35% Nr or greater centrifugal forces pull the flap restraints out allowing conning of the blades, as the speed increases to ~70% Nr the droop stops will come out
Droop stops will reseat at approximately 50% Nr
What makes up the Rotor Blades?
- Pressurized hollow spar, honeycomb core, and outer skin
- Electrothermal deicing mats
- Abrasion strips
- Removable swept-back blade tip faring (20°)
How much are the tip caps swept and what are their purpose?
They are swept back 20° and provide sound attenuation and increase rotor blade efficiency
How do you know if a blade is damaged?
The nitrogen inside of the blades wil leack out and the Balde Inspection Method (BIM) will be black
how much is the tail rotor canted?
How much lifting force does it provide?
The Tail Rotor is mounted on the right side of the tail pylon canted at 20° providing 2.5% of total lifting force while in a hover
What does the Tai Rotor Indexer do?
Positions the Tail rotor during fold operations and prevents the trail rotor from windmilling in winds up to 60 knots when the tail is folded.
What does the tail rotor quadrant do?
It transmits tail rotor cable movements to the tail rotor servo. Two spring cylinders allow the quadrant to function normally if ONE of the cables breaks
What are the Tail rotor blades made of?
How do control inputs get moved to the blade spars?
Two interchangeable tail rotor blade spars have abrasion strips and electrothermal blankets for deicing.
A pitch change shaft extends through the center of the tail gearbox connecting to a pitch change crossbeam, which flexes all the spars simultaneously through pitch change links.
What does the Gust Lock do?
It’s primary function is to lock the rotor disk break in the indexed position and prevent the rotor break disk from turing inadventently should the Rotor break hydraulic pressure bleed off while the rotors are spread.
It will also position the blades during the folding sequence
How does the Active Vibration Control System work?
What does NATOPS say about its use on deck?
5 Force Generators receive input from 10 feedback accelerometers and generates a destructive counter force to reduce the 4 per vibration created by the rotor head
Extended time on deck with the AVCS operating should be avoided, every 5min it resets its vibration nulling solution, and depending on the surface it could input an erroneous solution.
