曝光台 注意防骗
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• Positioning the control bar toward the front tube
• Detecting a stall condition by visually noting the
attitude of the aircraft for the power setting
6-22
• Hearing the wind decrease on the structure and
pilot
• Feeling the wind decrease against the pilot
• Sensing changes in direction or speed of motion,
or kinesthesia—probably the most important and
best indicator to the trained and experienced pilot.
If this sensitivity is properly developed, it warns of
a decrease in speed or the beginning of a settling or
mushing of the aircraft.
During the practice of intentional stalls, the real objective
is not to learn how to stall an aircraft, but to learn how to
recognize an approaching stall and take prompt corrective
action. Though the recovery actions must be taken in a
coordinated manner, they are broken down into the following
three actions for explanation purposes.
First, at the indication of a stall, the pitch attitude and angle
of attack must be decreased positively and immediately.
Since the basic cause of a stall is always an excessive angle
of attack, the cause must fi rst be eliminated by releasing the
control bar forward pressure that was necessary to attain that
angle of attack or by moving the control bar backwards. This
lowers the nose and returns the wing to an effective angle
of attack.
The amount of movement used depends on the design of
the wing, the severity of the stall, and the proximity of the
ground. In some WSC aircraft, the bar can be left out and
as the nose stalls, the wing lowers to an angle of attack and
keeps fl ying since the tips do not stall. However, even though
WSC aircraft generally have gentle stall characteristics,
higher performance wings may not be as forgiving. Therefore
during a stall, the control bar should be moved back to reduce
the angle of attack and properly recover from the stall. The
object for all WSC aircraft is to reduce the angle of attack
but only enough to allow the wing to regain lift as quickly as
possible and obtain the appropriate airspeed for the situation
with the minimum loss in altitude.
Power application in a stall is different than an airplane. Since
power application in a WSC aircraft produces a nose-up
moment after a stall has occurred and the pitch has decreased
from the control bar movement, power should be applied.
The fl ight instructor should emphasize, however, that power
is not essential for a safe stall recovery if suffi cient altitude
is available. Reducing the angle of attack is the only way of
recovering from a stall regardless of the amount of power
used. Stall recoveries should be practiced with and without
the use of power. Usually, the greater the power applied
during the stall recovery, the less the loss of altitude.
Third, straight-and-level fl ight should be regained with
coordinated use of all controls. Practice of power-on stalls
should be avoided due to potential danger of whipstalls, tucks,
and tumbles, as detailed later in ths chapter.
Power-off (at idle) turning stalls are practiced to show
what could happen if the controls are improperly used
during a turn from the base leg to the fi nal approach. The
power-off straight-ahead stall simulates the attitude and
fl ight characteristics of a particular aircraft during the fi nal
approach and landing.
Usually, the first few practices should include only
approaches to stalls with recovery initiated as soon as the
fi rst buffeting or partial loss of control is noted. Once the
pilot becomes comfortable with this power-off procedure,
the aircraft should use some power and be slowed in such
a manner that it stalls in as near a level pitch attitude as is
possible. The student pilot must not be allowed to form the
impression that in all circumstances a high pitch attitude is
necessary to exceed the critical angle of attack, or that in all
circumstances a level or near level pitch attitude is indicative
of a low angle of attack. Recovery should be practiced fi rst
without the addition of power by merely relieving enough
control bar forward pressure that the stall is broken and the
aircraft assumes a normal glide attitude. Stall recoveries
should then be practiced with the addition of power during
the recovery to determine how effective power is in executing
a safe recovery and minimizing altitude loss.
Stall accidents usually result from an inadvertent stall at a
low altitude in which a recovery was not accomplished prior
to contact with the surface. As a preventive measure, stalls
should be practiced at a minimum altitude of 1,500 feet
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Weight-Shift Control Aircraft Flying Handbook(81)
