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
ahead with minimum loss of altitude, and accomplished in
accordance with the recovery procedure discussed earlier.
6-24
Whip Stall and Tumble Awareness
As discussed in chapter 2, the WSC aircraft does not have a
tail with a vertical stabilizer similar to an airplane, and there
is the possibility of the wing tucking and tumbling. If a WSC
tumbles, this will most likely result in a structural failure
of the WSC and serious injury or death to the pilot and/or
passenger. It is most important for the pilot to understand
tumble awareness and use all means to avoid such an
occurrence. The pilot can avoid a tuck and tumble by:
• Flying within the manufacturer’s limitations.
• Flying in conditions that are not conducive to tucks
and tumbles.
• Obtaining the proper training in pitch stability for the
WSC.
Flying within the manufacturer’s pitch and airspeed
limitations is simply adhering to the POH/AFM limitations.
Depending on the manufacturer, this could mean no full
power stalls, not exceeding pitch limits of ± 40 pitch angle,
not fl ying below the safe fl ying speed in turbulence, etc.
Manufacturer’s limitations are provided for the specifi c
aircraft to avoid tucks and tumbles.
Prefl ight preparation is the fi rst step to avoid the possibility
of a tuck/tumble to avoid fl ying in strong weather conditions.
This could be strong winds that create wind shear or strong
convective thermals that create updrafts and downdrafts. This
weather analysis is part of the prefl ight preparation weather
analysis. The second pilot decision regarding appropriate
weather while fl ying is to look at the environment during
fl ight to understand and evaluate the situation. Weather
conditions should always be evaluated as the fl ight progresses
with ADM used to determine the best outcome for the
situation. This could be turning back or landing depending
on the situation.
As a student or pilot progresses, turbulence will be
encountered. Use the procedures for fl ying straight and level
as shown in Figure 6-8. Use this exercise as a foundation for
developing pitch control awareness to keep the wing managed
with proper control bar pitch and throttle control.
For high pitch angles, the POH may have specifi c procedures
that should be followed for the particular WSC aircraft,
but the following general guidelines are provided. After
reviewing the aerodynamic aspects of the tuck/tumble in
chapter 2, refer to the following tuck/tumble awareness and
avoidance procedures.
As defi ned in the aerodynamics section, a whip stall is a high
pitch angle when the tips stall because they exceed the critical
angle of attack. This can be the result of strong turbulence
or power-on stall, pilot induced, or any combination of
these factors. A pilot must avoid all of these factors to avoid
the possibility of a whip stall resulting in a tumble, but the
following procedures are provided for tumble avoidance
in case a whip stall or a nose rotating down below the
manufacturer’s limitations is encountered.
The aircraft rotates nose down. [Figure 6-23,
Whip Stall to Phase 1] Push the control bar out to the
front tube and level wings while increasing to full power
and keeping control bar full out to reduce overpitching.
[Figure 6-23, Phase 1 to Phase 2] If rotation is so severe that
it progresses to phase 4 and the WSC aircraft is tumbling, the
ballistic parachute (if so equipped) should be deployed.
There are other weather situations in which the nose is not
at a high pitch attitude, where the back of the wing can get
pushed up and enter phase 1 without an unusually high pitch
attitude or whip stall. If pitched nose low, increase to full
power while pushing the control bar full out to reduce nosedown
pitching rotation. Generally, the control bar full out
and full throttle create a nose-up moment.
It takes extremely strong weather conditions and/or pilot
error to tuck/tumble a WSC aircraft. Experienced pilots fl y
all day in moderate turbulence, but building experience fl ying
in turbulence should be approached slowly and cautiously to
determine the pilot and aircraft capabilities and limitations.
A Scenario
The following is one example of a scenario that could lead to
a tuck/tumble. It is based on a viable training program in one
location but lack of experience in another location.
A student obtains his or her pilot’s license with the minimum
number of hours for the pilot certifi cate. The new pilot trained,
soloed, and obtained his or her license only in conditions near
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：
Weight-Shift Control Aircraft Flying Handbook(83)
