12.02 Flight Control Systems Flashcards
(34 cards)
What is the axis perpendicular to the main body axis and also horizontal?
Pitch
What is the axis parallel to the main body axis from the cockpit to the tail boom of the helicopter?
Roll
What are the two functions of the anti-torque pedals?
Controlling/counteracting main rotor torque and directional control
How is movement of the collective control lever prevented from affecting the cyclic lever and vice versa?
A mechanical coupling between the collective pitch channel and the cyclic channel (Mixer unit) is used.
Why are rod ends adjustable?
To facilitate changing the length of the control rod for rigging purposes.
What is the vertical centreline of the aircraft from top to bottom?
Yaw
What does ‘NOTAR’ stand for?
No TAil Rotor
What is another term for a Fenestron tail rotor?
Ducted or Shrouded Fan
What advantages does a Fenestron tail rotor have over conventional tail rotors?
Quieter
No blade tip vortices
Increased tail rotor thrust
Safer to ground crew
Tail rotor strikes reduced
What boundary layer control does the NOTAR system use?
The Coanda Effect
How is directional control achieved with the NOTAR system?
Rotating direct jet thruster
During forward flight, how is the majority of anti-torque provided with the NOTAR system?
By the vertical stabilizers
What advantages does a NOTAR system have over conventional tail rotor designs?
The design eliminates need for drive shafts, bearings and gearboxes
What are the 4 major types of main rotor head systems?
Fully articulated
Semi-rigid
Rigid
Hinge- and bearing-less
What is the name of the horizontal hinge in a fully-articulated main rotor head and what is its purpose?
The Flapping hinge – compensates for dissymmetry of lift
What is the name of the vertical hinge in a fully-articulated main rotor head and what is its purpose?
The Drag or lead-lag – compensates for Coriolis effect.
How is excessive movement about the vertical hinge prevented?
By the use of Drag or Lead-Lag dampers
How does the semi-rigid main rotor head compensate for movements?
The rotor flaps as a unit about a Teetering hinge
How are fore and aft movements compensated in a semi-rigid main rotor head?
By the elasticity of the rotor blades
How are flapping and fore/aft movements compensated in a rigid main rotor head?
They are compensated for by the flexibility of the composite rotor blades
How are feathering and flapping movements achieved in hinge- and bearing-less rotor heads?
By the use of composite flex-beams, which attach the blades to the hub
What are the 3 major types of blade dampers?
Hydraulic cylinder
Multiple disc
Elastomeric
What else is inside a multiple disc damper besides the discs and plates?
Hydraulic fluid to cool and lubricate the inside of the damper
What material is found in an elastomeric damper?
Rubber and aluminium
