FLIGHT CONTROL SYS Flashcards
Name the four types of mechanical compensation (control mixing) and the one type of electrical compensation.
Collective to yaw
Collective to lateral
Collective to longitudinal
Yaw to longitudinal
Collective / airspeed to yaw
Collective to yaw (control mixing)
main rotor torque causes the nose of the aircraft to yaw to the right with increased collective
to compensate, the tail rotor thrust is increased
Collective to lateral (control mixing)
the tractor tail rotor causes the helo to drift right with increased collective
to compensate, the rotor disc is tilted to the left
Collective to longitudinal (control mixing)
rotor downwash on the stabilator causes the nose to pitch up and the helo to drift aft with increased collective
to compensate, the rotor disc is tilted forward
Yaw to longitudinal (control mixing)
the tail rotors 2.5% lift factor causes the nose to pitch down and the helo to drift forward when left pedal is applied
to compensate, the rotor disc is tilted aft
Collective / airspeed to yaw (control mixing)
because the tail pylon is a vertical airfoil, the nose will tend to yaw to the left as airspeed increases which means that less anti-torque is required
the trim will compensate by washing out pedal requirements as airspeed increases
How are the cyclic, collective, and pedal flight control inputs routed to the rotor system?
routed aft and outboard of each pilot seat, vertically up each side of the aircraft, and are combined for each axis at the overhead torque shafts in the hydraulics bay.
the overhead torque shafts transfer inputs through the pilot assist servos and the mixing unit.
from the mixing unit, the FAL inputs are transferred to the swashplate assembly via the primary servos and the bridge assembly.
from the swashplate, the inputs move upward through the pitch control rods to the pitch change horns
What type of system is our main rotor?
fully articulated system
How is the swashplate assembly attached to the low pressure plate?
the rotating and stationary swashplate are attached to a low pressure plate via the rotating scissors
The main rotor blades are attached to the rotor head via a _____ ______ ______.
hinged spindle assembly
What enables the main rotor blades to flap, lead/lag, and move for pitch changes?
elastomeric bearings
What prevents extremely high/low blade flapping at low Nr?
droop stops and flap restraints
The main rotor blades have _______ swept tips to increase efficiency and ________ to extend their useful life.
20 degree, abrasion strips
What type of system is our tail rotor?
crossbeam blade system
How many degrees is our tail rotor canted?
20 degrees
Explain the spring tension and centering spring feature in the tail rotor.
there are two spring cylinders connected to the quadrant that provide tension to the tail rotor cables.
the spring tension feature allows for a fail safe if one cable breaks whereas the centering spring allows for present spring-loaded position of the tail rotor in the event both cables fail.
either failure will trigger the [TAIL ROTOR QUADRANT] caution
Explain the fly home capability of the tail rotor system.
if both tail rotor cables fail, the fixed tail rotor setting provides a fly home capability of balanced flight to a 19,500 lb. aircraft on a standard day at sea level at 25 or 145 kts.
Which direction will the nose want to go in a cable failure at 100 kts in a 19,500lb. aircraft on a standard day?
Left
How do the cable failure airspeeds change if the aircraft is heavier than 19,500lb.?
the airspeed range decreases, i.e. above 25kts and below 145kts
