M11.1 Flashcards
What do spoilers do
Used to supplement aileron control by reducing lift on the wing with the upgoing aileron.
Counteracts the effects cog lift induced drag that causes adverse yaw
What is a stabilitor
Similar to the elevator but the whole stabiliser moves
What are variable incidence stabilisers
Trimmable horizontal stabilisers
Used for pitch trimming
Accounts for movements in passenger and freight distribution.
What are canards and what do they do and where are they on the aircraft.
Canards are ahead of the main wings.
Used for : pitch control ; stability ; and stall prevention.
Canards stall first resulting in a nose down motion.
Useful for high angle of attack manoeuvres
Control redundancy.
If not designed properly it can lead to issues.
What is the relationship between roll and yaw.
A drag imbalance causes adverse yaw when in a roll.
Frise ailerons are used to combat this. So are the rudder-aileron interconnect system.
Yaw control
Which control surface controls yaw?
What do (BLANK) limiters do?
Rudder.
Rudder limiters restricts amount of rudder deflection at speed, controlled by the FLC computers.
Elevons and ruddervators
Elevons:
With delta aircraft there is no horizontal stabilisers.
Ruddervators:
Combines elevators and rudders
V-tailed aircraft
Slots and slats
Slots and slats allow for the boundry layer to be re-energised which helps prevent stall.
Slats are retractable version of slots.
Flaps
Secondary flight control.
Significant drag.
Raises the lift coefficient.
Moves centre of pressure rearwards creating a nose down tendancy
Plain flap
Looks like a control surface.
Flaps on both wings are linked.
50-55% more lift.
Split flap
Avoids boundry layer seperation.
More drag
60-65% more lift
Slotted flap
Allows for boundry layer re-energisation
Not as much drag.
Increases camber of the wing but not the wing area.
65-70% more lift.
Fowler flap
Split flap that forms part of the underside of the trailing edge.
Moves rearwards and downwards.
95% more lift.
Slotted fowler flap
Leading edge flaps
Used in conjunction with the trailing edge flaps.
Retract into leading edge.
Leading edge droop flap.
Increases camber and lift.
Rotate forwards whereas slats just move away.
Kruger flap
Nose up pitching.
Slot is produced.
More pronounced, blunt leading edge.
Flaperons
An aileron that can also function as a flap.
Droop with flaps bu still moves differentially.
What 3 key functions do spoilers have
Flight spoilers (speed brakes).
Ground spoilers (lift dumpers)
Roll spoilers.
What are the primary flight controls.
Ailerons, elevators and rudders (roll spoilers on large aircraft)
Swept wing aircraft are especially vulnerable to __________ during rolll and yaw.
How is it prevented.
Oscillations known as Dutch roll.
Minimised by a yaw dampening system.
How are differential ailerons rigged in a special way to counter adverse yaw?
The up going aileron is deflected a greater distance then the down going aileron which creates more drag
Where are élevons used
Delta wing ac
When are ruddervators used
V-tailed ac
What effect does span wise flow have
Thickens the boundry layer toward the wing tip, making it prone to separation if the angle of attack is increased.
What do saw tooth leading edges achieve?
Creates small vortexes which acts to redirect the spanwise flow.
Prevents stagnation of flow over wing tips and control surfaces but does add drag.
What is the purpose of trim tabs
Used to compensate for the imbalance of the a/c.
Adjusted on the ground.
What are balance tabs and what do they do.
Crates a force on the control surfaces but does that assists in its movement. Does this by producing a low static pressure over the control surface.
Reduces the efficiency of the control surface.
What are anti balance tabs and what do they do.
May be used where controls are too sensitive.
Assists in moving control surfaces back to neutral.
Increases effectiveness of control surface.
Requires more force to move the control surface.
What are servo tabs and what do they do
Used on larger ac.
Operated by the pilot.
Servo tab moves in opposite direction to the flying control. (Like a balance tabs).
The force produced moves the flying control.
There is no direct control of the flying controls.
What do spring tabs do and how do they operate.
Is like a servo tab but only works when the force on a flying control surface reaches a certain value.
