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时间:2010-05-10 17:47来源:蓝天飞行翻译 作者:admin
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nate shock cooling, and to reduce the possibility of inflight
fire, the manufacturer provides engine cooldown
procedures to reduce engine system
temperatures prior to shutdown. Reducing throttle setting
allows the engine to begin a gradual cool down.
The GFM/POH may also instruct the pilot to adjust
propeller pitch at this time. Lowering the nose to
increase airspeed provides faster flow of cooling air to
the engine cooling system. Several minutes of reduced
throttle and increased cooling airflow are enough to
allow the engine to be shut down. If the engine is
retractable, additional time after engine shutdown may
be necessary to reduce engine temperature to acceptable
limits prior to retracting and stowing the engine in
the fuselage. Consult the GFM/POH for details.
[Figure 7-24]
Retractable-engine self-launch gliders are aerodynamically
efficient when the engine is stowed, but produce
high-drag when the engine is extended and not providing
thrust. Stowing the engine is critical to efficient
soaring flight. Prior to stowing, the propeller must be
aligned with the longitudinal axis of the glider, so the
propeller blades do not interfere with the engine bay
doors. Since the engine/propeller installation in these
gliders is aft of the pilot’s head, these gliders usually
have a mirror, enabling the pilot to perform a visual
propeller alignment check prior to stowing the
engine/propeller pod. Detailed instructions for stowing
the engine and propeller are found in the GFM/POH
for the particular glider. If a malfunction occurs during
engine shutdown and stowage, the pilot cannot count
on being able to get the engine restarted. The pilot
should have a landing area within power-off gliding
distance in anticipation of this eventuality.
Some self-launch gliders use a nose-mounted engine/propeller
installation that resembles the typical installation
found on single-engine airplanes. In these self-launch
gliders, the shutdown procedure usually consists of
operating the engine for a short time at reduced power
to cool the engine down to acceptable shutdown temperature.
After shutdown, the cowl flaps, if installed,
should be closed to reduce drag and increase gliding
efficiency. The manufacturer may recommend a time
interval between engine shutdown and cowl flap closure,
to prevent excess temperatures from developing
in the confined, tightly cowled engine compartment.
These temperatures may not be harmful to the engine
itself, but may degrade the structures around the
engine, such as composite engine mounts or installed
electrical components. Excess engine heat may result
in fuel vapor lock.
If the propeller blade pitch can be controlled by the
pilot while in flight, the propeller is usually set to
coarse pitch, or if possible, feathered, to reduce propeller
drag during non-powered flight. Some selflaunch
gliders require the pilot to set the propeller to
coarse pitch prior to engine shutdown. Other selflaunch
gliders require the pilot to shut down the engine
first, then adjust propeller blade pitch to coarse pitch or
to feathered position. As always, follow the shutdown
procedures described in the GFM/POH.
COMMON ERRORS
• Failure to follow manufacturer’s recommended
procedure for engine shutdown, feathering,
and stowing procedure (if applicable).
• Failure to maintain positive aircraft control
while performing engine shutdown procedures.
LANDINGS
If the self-launch glider is to land under power, the pilot
should perform the engine restart procedures at a safe
altitude to allow time to reconfigure. The pilot should
follow the manufacturer’s recommended pre-starting
checklist. Once the engine is started, the pilot should
allow time for it to warm up. After the engine is started
the pilot should ensure that all systems necessary for
landing are operational, such as the electrical system
and landing gear.
The pilot should fly the traffic pattern so as to land
into the wind and plan the approach path to avoid all
obstacles. The landing area should be of sufficient
Figure 7-24.Types of self-launch gliders. length to allow for touchdown and roll-out within the
7-22
performance limitations of the particular self-launch
glider. The pilot should also take into consideration
any crosswind conditions and the landing surface.
After touchdown, the pilot should maintain direction
control, and slow the self-launch glider so as to clear
the landing area. The after landing checklist should be
completed when appropriate.
 
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