曝光台 注意防骗
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To determine the degree of controllability, the pilot
must be conscious of the reaction of the airplane to
the control pressures and immediately adjust the
pressures as needed to control the airplane. The pilot
must wait for the reaction of the airplane to the
applied control pressures and attempt to sense the
control resistance to pressure rather than attempt to
control the airplane by movement of the controls.
Balanced control surfaces increase the importance
of this point, because they materially reduce the
intensity of the resistance offered to pressures
exerted by the pilot.
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5-3
At this stage of training, beginning takeoff practice, a
student pilot will normally not have a full appreciation
of the variations of control pressures with the speed of
the airplane. The student, therefore, may tend to move
the controls through wide ranges seeking the pressures
that are familiar and expected, and as a consequence
over-control the airplane. The situation may be aggravated
by the sluggish reaction of the airplane to these
movements. The flight instructor should take measures
to check these tendencies and stress the importance of
the development of feel. The student pilot should be
required to feel lightly for resistance and accomplish
the desired results by applying pressure against it. This
practice will enable the student pilot, as experience is
gained, to achieve a sense of the point when sufficient
speed has been acquired for the takeoff, instead of
merely guessing, fixating on the airspeed indicator, or
trying to force performance from the airplane.
LIFT-OFF
Since a good takeoff depends on the proper takeoff
attitude, it is important to know how this attitude
appears and how it is attained. The ideal takeoff attitude
requires only minimum pitch adjustments
shortly after the airplane lifts off to attain the speed
for the best rate of climb (VY). [Figure 5-2] The pitch
attitude necessary for the airplane to accelerate to VY
speed should be demonstrated by the instructor and
memorized by the student. Initially, the student pilot
may have a tendency to hold excessive back-elevator
pressure just after lift-off, resulting in an abrupt pitchup.
The flight instructor should be prepared for this.
Each type of airplane has a best pitch attitude for
normal lift-off; however, varying conditions may
make a difference in the required takeoff technique.
A rough field, a smooth field, a hard surface runway,
or a short or soft, muddy field, all call for a slightly
different technique, as will smooth air in contrast to
a strong, gusty wind. The different techniques for
those other-than-normal conditions are discussed
later in this chapter.
When all the flight controls become effective during
the takeoff roll in a nosewheel-type airplane, backelevator
pressure should be gradually applied to
raise the nosewheel slightly off the runway, thus
establishing the takeoff or lift-off attitude. This is
often referred to as “rotating.” At this point, the
position of the nose in relation to the horizon should
be noted, then back-elevator pressure applied as
necessary to hold this attitude. The wings must be
kept level by applying aileron pressure as necessary.
The airplane is allowed to fly off the ground while in
the normal takeoff attitude. Forcing it into the air by
applying excessive back-elevator pressure would only
result in an excessively high pitch attitude and may
delay the takeoff. As discussed earlier, excessive and
rapid changes in pitch attitude result in proportionate
changes in the effects of torque, thus making the airplane
more difficult to control.
Although the airplane can be forced into the air, this is
considered an unsafe practice and should be avoided
under normal circumstances. If the airplane is forced
to leave the ground by using too much back-elevator
pressure before adequate flying speed is attained, the
wing’s angle of attack may be excessive, causing the
airplane to settle back to the runway or even to stall.
On the other hand, if sufficient back-elevator pressure
is not held to maintain the correct takeoff attitude after
becoming airborne, or the nose is allowed to lower
excessively, the airplane may also settle back to the
runway. This would occur because the angle of attack
is decreased and lift diminished to the degree where it
will not support the airplane. It is important, then, to
hold the correct attitude constant after rotation or liftoff.
As the airplane leaves the ground, the pilot must
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AIRPLANE FLYING HANDBOOK 飞机飞行手册上(54)
