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Pilot ControlsA pilot has 3 main controls
to move the aircraft about its 3 axes.
Ailerons, Elevators and a Rudder
Using these controls the pilot can:
Pitch – make the nose rise or fall Roll – make one wing rise and the other fall
Yaw – make the nose move left or right
Elevators
Rudder
Ailerons
The Pitching Plane
Elevators make the aircraft nose rise or fall.
They are hinged to the trailing edge of the tailplane,
and linked to the pilots control column – ‘The Stick’
The Pitching PlaneMoving the stick forwards
lowers the elevators,
and gives an angle of attack which creates lift,
and the aircraft is tail-up, nose–down,
about its lateral axis.
Lift
Control ColumnPushed Forward
Lateral Axis
αAngle of Attack
The Pitching PlaneMoving the stick backwards
raises the elevators,creating the opposite effect,
and the aircraft is tail-down, nose–up,about its lateral axis.
Control ColumnPulled Backward
Lift
Lateral AxisαAngle of Attack
The Rolling Plane
Ailerons make the aircraft roll about its longitudinal axis.
They are hinged to the trailing edge of each wing.
and linked to the pilots control column – ‘The Stick’
Moving the stick to the left raises the LEFT aileronand depresses the RIGHT aileron.
The left aileron has a reduced angle of attackand reduced lift
The right aileron has an increased angle of attackand increased lift
The aircraft rolls to the left about its longitudinal axis.
The Rolling Plane
Control ColumnPushed LEFT
Lift
Lift
The Rolling PlaneMoving the stick to the right raises the RIGHT aileron
and depresses the LEFT aileron,creating the opposite effect,
and the aircraft rolls to the rightabout its longitudinal axis.
Control ColumnPushed RIGHT Lift
Lift
The Yawing Plane
The Rudder makes the aircraft nose move left or right.
It is hinged to the trailing edge of the fin,
and linked to the rudder pedals in the cockpit.
Moving the LEFT pedal forwards
moves the rudder to the left,
this produces a sideways force to the right.
The tail is pushed to the right
and the nose moves to the left.
The Yawing Plane
Force
Rudder PedalsLEFT Forwards
Original
Flight Path
New
Flight Path
The Yawing PlaneMoving the RIGHT pedal forwards
moves the rudder to the right,creating the opposite effect,
The tail is pushed to the left
and the nose moves to the right.
ForceRudder PedalsRIGHT Forwards
Original
Flight Path
New
Flight Path
Trimming Tabs, Flaps & Slats
The weight and position of an aircraftsCentre of Gravity can change when:
Fuel is used, Bombs dropped, Ammunition fired, etc.
The Centre of Pressure will also change due to:
Change in Power, Speed and Attitude
All these changes will affect the balance of forceson the aircraft
There are a number mechanisms that assist pilotsin these cases.
Trimming TabsHelp comes in the form of ‘trimming tabs’,
which are hinged to the trailing edgesof the elevators, ailerons and rudder.
Aileron Trim Tab
Elevator Trim Tabs
Rudder Trim Tab
Aileron Trim Tab Pull Force
Stick Force Remains
+ + + + +
+
Larger Moment Arm
Stick Force Removed
Flaps
An aircraft’s wing is designed
so that the aircraft can make its approach
at a controlled slow speed,
along a moderately steep approach path.
A well-proven solution is to add flaps
for use on the approach and landing.
FlapsFlaps are hinged surfaces
usually fitted to the trailing edge of wings
before the ailerons to increase lift.
FlapsFlaps
Blown Flap
Plain Flap(or Camber)
Split Flap
Fowler Flap
Slotted Flap
50% Increase CLMAX Critical Angle 12o
60% Increase CLMAX Critical Angle 14o
65% Increase CLMAX Critical Angle 16o
80% Increase CLMAX Critical Angle 16o
90% Increase CLMAX Critical Angle 15o
FlapsDrag Effects on Flaps
Flaps 30oFlaps 90oFlaps 60o
Flap
30o
60o
90o
Drag
Small Inc
Large Inc
V Large Inc
Lift
Large Inc
Small Inc
No Sig Inc
SlatsSlats improve handling at low speeds.
They are small aerofoils positioned along the
leading edge of each wing.
SlatsSlats
Automatic Slat
70% Increase CLMAX Critical Angle 25o
Fixed Slat
50% Increase CLMAX Critical Angle 20o
Open Slat
40% Increase CLMAX Critical Angle 20o
Kruger Slat
50% Increase LLMAX Critical Angle 25o
Droop Snoot Slat
50% Increase CLMAX Critical Angle 20o
SlatsIf the wing reaches a high angle of attack,
the slat opens.
Air can now flow between the slat and the wing.
The shape of the slot accelerates air through it improving the pattern of airflow over it.
Direction of airflow
Slat
Direction of airflow
Lift AugmentationEffects on CL
α
BASIC AEROFOIL SECTIONCL
TRAILING EDGE FLAP
LEADING EDGE FLAP
SLAT OR SLOT
CL(the ratio between
lift and dynamic pressure).
Check of UnderstandingIn position 1 the aircraft is climbing vertically.
To make the aircraft move to position 2 and then 3,Which way must the pilot move the control column?
Forward
To the right
Backward
To the left
Check of UnderstandingWhat control would a pilot use
to make an aircraft roll?
Elevator
Aileron
Rudder
Fin
Check of UnderstandingOn the diagram, what does the arrow point at?
The aileron
The elevator trimming tab
The fin
The rudder trimming tab
Check of UnderstandingWhat will happen if flaps are lowered
during the approach to land?
The stalling speed will be increased
Drag will be decreased
A higher touch-down speed is needed
Lift will be increased