Transcript Prin of Flt Pt 3

Principles of Flight
Leading Cadet Training
Stability and Control
Lecture
3
Planes & Axes
There are 3 AXES that an aircraft rotates on,
(all at 90o to one another)
The Longitudinal Axis
The Lateral (or Horizontal) Axis
and the Normal (or Vertical) Axis
All 3 Axes pass through The Centre of Gravity.
Centre of Gravity
Longitudinal
Normal
(Vertical)
Lateral
(Horizontal)
Planes & Axes
There are 3 PLANES that an aircraft moves in,
(rotating on an axis)
The Pitching Plane about its Lateral (Horizontal) Axis
(moving the nose up or down)
The Rolling Plane about its Longitudinal Axis
(moving the wings up or down)
The Yawing Plane about its Normal (Vertical) Axis
(moving the body left or right)
Pitch
Yaw
Centre of Gravity
Longitudinal
Roll
Normal
(Vertical)
Lateral
(Horizontal)
Planes & Axes
The 3 AXES and the 3 PLANES
give STABILITY to the aircraft.
Axis
Plane
Stability
Lateral
Pitching
Longitudinal
Longitudinal
Rolling
Lateral
Normal
Yawing
Directional
Pitch
Yaw
(Directional)
(Longitudinal)
Roll
(Lateral)
Centre of Gravity
Longitudinal
Normal
(Vertical)
Lateral
(Horizontal)
The Pitching Plane
The tailplane meets airflow at an Angle of Attack of 0°
Regardless if the nose pitches UP or DOWN
the tailplane will still have an Angle of Attack
to the oncoming air.
This produces lift which puts the aircraft
back into a level flight position.
This means that the tailplane produces
Oncoming
air in the pitching plane.
stability
α
Oncoming Air
Oncoming air
Tailplane
α
The Rolling Plane
If the wing drops in turbulent air
the aircraft begins to slip sideways,
and a sidewind strikes it.
Because of the angle of the wings
they meet the sidewind at an ‘angle of attack’
which is greater on the lower wing than the upper.
This produces lift
rolling the aircraft until the wings are level.
Slip
α
Sidewind
α
The Yawing Plane
If an aircraft Yaws to one side by an air disturbance,
it continues to ‘crab’ in its original direction,
with a sidewind blowing on its fin surfaces.
On areas to the rear of the centre of gravity,
this sidewind produces a sideways force which,
will tend to yaw the aircraft back to its original heading.
Large sufficient fin area therefore
produces stability in the Yawing Plane.
Sidewind
Force
Centre
of
Gravity
Stability
Aircraft movements such as
pitching, rolling and yawing
are always described in relation to the pilot.
Pitching
Rolling
Yawing
Control
Ailerons
Elevators
Rudder
Pilot Controls
A pilot has 3 main controls
to move the aircraft about its 3 axes.
Elevators, Ailerons 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
Ailerons
Rudder
The Elevators
Are hinged to the trailing edge of the tailplane.
Moving the control column forwards
lowers the elevators,
and gives an angle of attack which creates lift,
and the aircraft is tail-up, nose–down,
pitching about its lateral axis.
Lateral Axis
Lift
Angle of Attack
α
Moving the stick backwards raises the
elevators, creating the opposite effect.
The Ailerons
Are hinged to the trailing edge of each wing.
Moving the control column to the left
raises the LEFT aileron
and depresses the RIGHT aileron.
The left aileron has a reduced angle of attack
and reduced lift
The right aileron has an increased angle of attack
and increased lift
Moving the
stick to the right
Lift
creates the opposite effect,
Ailerons therefore control
Lift
the aircraft in the rolling plane.
The Rudder
Is hinged to the trailing edge of the fin.
Moving the LEFT rudder pedal forwards
moves the rudder to the left,
this produces a sideways force to the right.
The tail is now pushed to the right
and the nose moves to the left.
Moving the RIGHT pedal forwards
creates the opposite effect.
Original
The rudder therefore
controls the aircraft
in the Yawing plane
Flight Path
New
Flight Path
Force
Check of Understanding
Aircraft movements such as pitching, rolling and
yawing are always described in relation to what?
The Horizon
The Pilot
The Ground
The Centre of Gravity
Check of Understanding
What are the three Axes about which
an aircraft can move?
Longitudinal, Lateral and Pitching
Yawing, Rolling and Pitching
Longitudinal, Lateral and Normal
Pitching, Yawing and Normal
Check of Understanding
What sort of movement is shown in the diagram?
Diving
Yawing
Rolling
Pitching
Check of Understanding
In order to control an aircraft in the pitching plane,
the pilot of an aircraft fitted with
conventional controls uses?
The Tail Fin
The Rudder
The Ailerons
The Elevators
Check of Understanding
The movement of an aircraft about its lateral axis
is called?
Yawing
Pitching
Rolling
Stalling
Check of Understanding
Which of these gives an aircraft
high directional stability in the Yawing plane?
A large fin area
A low centre of gravity
A small fin area
A high centre of gravity
Check of Understanding
The movement of an aircraft
about its normal axis is called?
Pitching
Yawing
Rolling
Damping
Check of Understanding
In 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?
To the right
To the left
Backward
Forward
Check of Understanding
For a particular aircraft,
which of these will reduce the stalling speed?
A reduction in weight
A reduction in power
Putting the aircraft into a turn
Raising the flaps
An Anhedral Angle
Check of Understanding
All the axes of rotation of an aircraft pass through?
Its centre of pressure
A point halfway between
the tail and the nose
Its centre of gravity
A point halfway between
a line between the wing tips
Principles of Flight
Leading Cadet Training
End of Presentation