曝光台 注意防骗
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· Acrobatic, 6 x gross weight
Naturally, there is a safety factor
involved, but the above should not
be exceeded.
Normal or utility categories do not
allow manoeuvres with high positive
and negative load factors. Bank
angles would normally be inside 60°.
Helicopters
A helicopter's fuselage will have the
tailboom and main rotors attached
to it. The most common landing
gear is skids:
But you may find wheels, too:
Flight Controls
When airflow over them is high, the
controls, when moved, have a
positive feel. They are less
responsive at slow speeds, which is a
point to remember when low and
slow (also, because of the nose high
attitude, the control surfaces may
not have any airflow over them at all,
which is why some aircraft have the
tail at the top of the fin). In fact, the
effectiveness of any control depends
on its distance from the Centre of
Gravity, the size of the control
surface, its speed through the air and
the degree of movement.
Control surfaces can be activated by
cables and pulleys, rods, tubes,
hydraulics or electrical signals.
Fly By Wire systems detect
movement of the controls, and
transducers send signals over
electrical cables to the system
concerned, which will be a selfcontained
unit in the relevant
location. There is some controversy
as to whether the programmers talk
to pilots, but the systems seem to
work well. Sometimes, sidesticks
replace conventional control
columns, as on the A-320 Airbus.
The controls will move the aircraft
in one of three axes – pitching (nose
up or down), rolling (wings up or
down) or yawing (nose left or right).
They do not move in isolation,
however – an adjustment in one
causes a secondary effect in another
and must be allowed for, as we shall
see in the discussions below. For
example, an uncontrolled yaw
eventually results in a roll, because
one wing will be moving faster and
will generate more lift on that side.
184 Canadian Professional Pilot Studies
Your instructor will need to
demonstrate certain manoeuvres,
and there is a well established system
of establishing who has control of
the aircraft at any given time. The
person handing over the controls
will say "You have control", while
the person receiving them replies
with "I have control".
Aeroplanes
The elevator, rudder and ailerons are
attached by hinges to the tailplane
(or horizontal stabiliser), fin and
wing trailing edges, respectively (a
Canard is a horizontal stabiliser
mounted on the front of the aircraft –
it has the advantage of a longer
moment arm, so the stabilising
surfaces can be smaller).
The elevator controls pitching by
increasing the angle of attack above
or below the tailplane, according to
whether it is raised up or forced
down by movement of the control
column in the cockpit (if the column
is pushed forward, the elevator is
forced down into the airflow
underneath the stabiliser, the angle
of attack is increased, the tail rises
because more lift is created and the
nose goes down, the opposite if
pulled back). Sometimes, there is no
elevator, but the whole stabiliser is
moved, in which case it is a stabilator.
The rudder does much the same
thing, only sideways, making the
nose yaw, or move left and right. It is
controlled by the foot pedals –
whichever one goes forward moves
the rudder to that side, where more
lift is created and the fin is forced
sideways in the appropriate
direction, to produce a flat turn with
a skid (you don't use the rudder to
turn, but to fine tune one initiated by
the ailerons, or stop it going the
wrong way – see Low and Slow).
The ailerons make the aircraft roll
around the nose. If you move the
control column to the left, the right
aileron goes down, increasing the
angle of attack on that side, and the
left one goes up, decreasing it,
causing a roll in the same direction.
To counteract Aileron Drag, which
comes from the downgoing aileron,
you might see frise or differential
ailerons used. With the former, the
downgoing aileron is streamlined.
The latter moves the down aileron
through a smaller angle.
In fact, the frise aileron's hinge is
offset, so a portion of the leading
edge of the downgoing aileron sticks
out into the airflow, to create a little
drag to reduce adverse yaw. It also
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