Flight Control System Flashcards
What are the 3 sections of the flight control system?
1 Mechanical control system
2 flight control servo system
3 automatic flight control system
Describe mechanical flight control system.
From control to mixing unit.
The flight controls are routed aft and outboard of each pilot seat, vertically up each side of the aircraft in our combined at the overhead torque shafts in the Hyd bay.
From the torque shafts the inputs from the trim servos and flight controls go to the pilot assist servos in the mixing unit.
Then fore, aft and lateral are transferred to the swashplate assembly via the primary servos and the bridge assembly.
The yaw inputs go to the tail rotor quadrant through the tail rotor cables.
If both tail rotor cables are severed what will happen?
Two centering springs will counter the tail rotor servo pilot valve and position the tail rotor to neutral setting.
The tail rotor cables provide mechanical input to the ________ which will ________________.
Tail rotor servo
Change the pitch change shaft, which move the pitch change beam, which moves the pitch change links and changes the pitch angle of the tail rotor.
The 2nd stage of the tail rotor servo is powered by what?
The backup pump
To secure the pitch and roll trim actuators you must________
Push the TRIM button on the AFCS control panel
The Boost servos do what?
Reduce cockpit control forces
And SAS system feedback
Control mixing:
Collective to yaw
Caused by main rotor torque
The nose yaws right when collective is increased
So tail rotor thrust is increased
Control mixing:
Collective to lateral
The helicopter drifts right when collective is increased
It’s caused by lateral lead from the tail rotor
So the rotor disc is tilted left
Control mixing:
Collective to longitudinal
Is caused by rotor down wash on the stab
The nose pitches up and the helicopter drifts aft when the collective is increased
So the rotor disc is tilted forward
Control mixing:
Yaw to Longitudinal
Is caused to the tail rotor lift vector
The nose pitches down and the helicopter drifts forward when left pedal is applied
So the rotor disc is tilted aft
Control mixing:
Collective/airspeed to yaw
The tail rotor pylon loads the side of the aircraft as speed increases
It forces the nose to yaw left as airspeed increases
So trim input is removed as the side load increases with airspeed
What does the pilot-assist servo assembly contain?
Boost servos
SAS actuators
Hydraulic (pitch and roll) trim actuators
Hydraulic power is required to move ___.
The primary servos
Are the Pitch and Roll trim actuators electrical or hydraulic?
What is the rest of the pilot-assist servos?
Hydraulic
Electrical
