4. Check No. 3 Part Power Trim.
Introduction. Prior to trimming, engine must be
brought up to its part power trim output and allowed to
run approximately five minutes to bring the engine to
normal operating temperatures.
Part Power Trim Stop. Fuel control units are
calibrated during bench test to insure maximum flow is
obtained. The trim stop must be adjusted to individual
engines on installation to insure maximum power on a
71°F (21°C) day. If engine inlet temperature is other
than this, it would not be possible to set the maximum
speed stop without first reaching either an interturbine
temperature or a torque limit. To overcome this, a part
power trim stop is provided. The stop is a movable
spacer placed between gas generator maximum speed
(Ng) stop and power lever anvil, and represents a 1700
rpm (Ng) speed drop. This stop is permanently attached
to the fuel control unit and is moved from the stowed
position for engine trimming.
Loosen screw (1) securing part power trim
stop (2) to gas generator maximum speed stop anvil.
Position part power trim stop so that it is
between power lever anvil and maximum gas generator
speed stop (3).
Tighten screw (1).
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