曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
Ch 03.qxd 7/13/04 11:08 AM Page 3-17
3-18
the airplane. Due to lack of experience, the beginning
student may be unable to recognize slight variations
of speed and angle of bank immediately by vision or
by the pressure required on the controls. Hearing will
probably be the indicator that will be the most easily
used at first. The instructor should, therefore, be certain
that the student understands that an increase in
the pitch of sound denotes increasing speed, while a
decrease in pitch denotes less speed. When such an
indication is received, the student should consciously
apply the other two means of perception so as to
establish the proper relationship. The student pilot
must use all three elements consciously until they
become habits, and must be alert when attention is
diverted from the attitude of the airplane and be
responsive to any warning given by a variation in the
feel of the airplane or controls, or by a change in the
pitch of the sound.
After a good comprehension of the normal glide is
attained, the student pilot should be instructed in the differences
in the results of normal and “abnormal” glides.
Abnormal glides being those conducted at speeds other
than the normal best glide speed. Pilots who do not
acquire an understanding and appreciation of these
differences will experience difficulties with accuracy
landings, which are comparatively simple if the
fundamentals of the glide are thoroughly understood.
Too fast a glide during the approach for landing
invariably results in floating over the ground for
varying distances, or even overshooting, while too
slow a glide causes undershooting, flat approaches,
and hard touchdowns. A pilot without the ability to
recognize a normal glide will not be able to judge
where the airplane will go, or can be made to go, in
an emergency. Whereas, in a normal glide, the flightpath
may be sighted to the spot on the ground on
which the airplane will land. This cannot be done in
any abnormal glide.
GLIDING TURNS—The action of the control
system is somewhat different in a glide than with
power, making gliding maneuvers stand in a class by
themselves and require the perfection of a technique
different from that required for ordinary power
maneuvers. The control difference is caused mainly by
two factors—the absence of the usual slipstream, and
the difference or relative effectiveness of the various
control surfaces at various speeds and particularly at
reduced speed. The latter factor has its effect
exaggerated by the first, and makes the task of
coordination even more difficult for the inexperienced
pilot. These principles should be thoroughly explained
in order that the student may be alert to the necessary
differences in coordination.
After a feel for the airplane and control touch have
been developed, the necessary compensation will be
automatic; but while any mechanical tendency exists,
the student will have difficulty executing gliding turns,
particularly when making a practical application of
them in attempting accuracy landings.
Three elements in gliding turns which tend to force the
nose down and increase glide speed are:
• Decrease in effective lift due to the direction of
the lifting force being at an angle to the pull of
gravity.
• The use of the rudder acting as it does in the entry
to a power turn.
• The normal stability and inherent characteristics
of the airplane to nose down with the power off.
These three factors make it necessary to use more back
pressure on the elevator than is required for a straight
glide or a power turn and, therefore, have a greater
effect on the relationship of control coordination.
When recovery is being made from a gliding turn, the
force on the elevator control which was applied during
the turn must be decreased or the nose will come up
too high and considerable speed will be lost. This error
will require considerable attention and conscious control
adjustment before the normal glide can again be
resumed.
In order to maintain the most efficient or normal glide
in a turn, more altitude must be sacrificed than in a
straight glide since this is the only way speed can be
maintained without power. Turning in a glide
decreases the performance of the airplane to an even
greater extent than a normal turn with power.
Still another factor is the difference in rudder action in
turns with and without power. In power turns it is
required that the desired recovery point be anticipated in
the use of controls and that considerably more pressure
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：
AIRPLANE FLYING HANDBOOK 飞机飞行手册上(36)
