11.9 FLIGHT CONTROLS Flashcards
What are the primary flight control surfaces
- ailerons
- elevators
- rudder
Explain balance tab
- tab moves opposite to flight control
- just for aerodynamic reasons
Explain servo tab
- opposite deflection
- moves flight control
Explain anti-balance tab
- tab moves same direction
- extra force needed for flight control position
Explain spring tab
- moves opposite direction
- helps control surface move when a certain force has been met
Explain lateral trim
- controlled by switch on centre console
- electrically controlled
Explain directional (yaw) trim?
- controlled by rotary knob on centre console
- electrically controlled
Why are the flaps lowered
- increase camber of wings
- provide greater lift and control at slow speeds
Why are composites becoming more common now
Due to weight saving
Explain Krueger flaps
- extendable lift enhancing device
- increases wing camber
- produces nose up pitching moment
When flaps are extended what is the nose pitch
- nose pitched down
Explain how roll spoilers work
Spoilers on one wing moves up and spoilers on the other wing stay down
Why is there a max deflection angle when deploying spoilers in flight
Prevent structural damage
Function of speed brakes
- increase drag (reduce aircraft speed)
Explain ground spoilers
- If ARMED they should automatically deploy
- dumps the lift
When properly maintained, how accurate is a tensiometer
98%
Explain tension regulators
- used due to expansion and contraction (temp change)
- e.g. if cable tightens, spring in regulator is compressed
Explain push-pull rods
Transmit forces in either direction
Disadvantage of push-pull rods than cables
Weight
Explain bell cranks
Change the direction of movement
Explain torque tubes
-angular or twisting motion is needed
- transmit torsional force
What are torque tubes often used to actuate
Ailerons, flaps and slats
Explain screw jacks
- used where moving surfaces that experience extreme aerodynamic loads
- convert rotary motion to linear
Explain damping mode
- servo unit is depressurised
- used as gust damper when aircraft on ground
Pneumatic systems on aircraft are primarily used as
- Back- up
- primary system
- secondary system
Back-up system
Explain fly-by-wire
Movement of flight controls are converted to electronic signals
Explain yaw damper
-swept back aircraft generate ‘Dutch roll’ motion
- yaw damper counters the rolling tendency
Explain rudder limiter
- Limiting control surface deflection during high speed operation
- reduce strain
Explain gust lock systems
- A lock for mechanical flight controls
