Rotor systems Flashcards
4 subsystems of the main rotor
main rotor blades
hub
flight controls
bifilar vibration absorber
what kind of rotor head to do we have
fully articulated
purpose of the elastomeric bearings
allow blades to flap, lead, lag and have pitch changes
purpose of dampers
restrain lead and lag absorb start loads
what is the main rotor head supported by
main rotor shaft extension which is secured by the lower pressure plate and main shaft nut
how do control inputs get to the rotor head from the stationary swashplate
to rotating swashplate then pitch control rods to the pitch change horns
when to anti flap restraints come out
around 35% Nr
when do droop stops come out
around 70% Nr
when do droop stops go in
around 50% Nr
describe the rotor blade
pressurized hollow spar, honeycomb core, outer skin, abrasion strips, electrothermal deice mats, removable swept back tip fairing
purpose of the swept back tip fairings
sound attenuation and efficiency
angle of swept back blade fairings
20 degrees
purpose of the electrothermal mat
allow for deicing of controls
purpose of abrasion strips
extend useful life of blades
what is the main rotor blade pressurized with
Nitrogen
how do we know if structural integrity of blade spar is in question
Black on BIM
what side of the aircraft are the tail rotors on
right
angle of tail rotor upward
20 deg
how much of the total lifting force in a hover does the tail provide
2.5%
what does the tail rotor quadrant do
transmits rotor cable movements to the tail servo
what happens if one tail cable breaks
the other cable is operated against spring tension and should provide normal responses
what happens if both tail cables break
springs put the servo in a setting reflecting an approximate mid position collective setting spot
how are the tail blades held on
sandwiched between two plates
describe the tail blades
two composite spars that are completely interchangeable
they have abrasion strips and electrothermal blankets for deicing
components of rotor brake sys
reservoir, master cylinder, gauge, relief valve assembly, accumulator, pressure switch, brake assembly, disc
purpose of back pressure spring in rotor brake system
holds pressure on rotor break in case of limited leak
where is the brake disc
on tail drive shaft output of MGB
purpose of the gust lock switch
main purpose is to support auto blade fold by locking it in a position and is also a mild redundancy to the rotor brake while the blades are spread
how long should you hold the gust lock switch minimum
5 seconds
AVCS components
AVCC
10 feedback accelerometers
Vibe control actuation system which has and electronics unit and 5 force generators
how long is the AVCS vibe nulling cycle
5 minutes
can you initiate AVCS IBIT with rotors static
yes
can you initiate AVCS IBIT with rotors spinning
shall not
