Cessna 208B - Engine Instruments; Quadrant Friction Lock; Torque Indicator

SECTION 7 CESSNA
AIRPLANE AND SYSTEMS DESCRIPTION MODEL 208B (675 SHP)
ENGINE (Continued)
QUADRANT FRICTION LOCK
A quadrant friction lock, located on the right side of the pedestal, is
provided to minimize creeping of the engine controls once they have
been set. The lock is a knurled knob which increases friction on the
engine controls when rotated clockwise.
ENGINE INSTRUMENTS
Engine operation is monitored by the following instruments: torque
indicator, propeller RPM indicator,
ITT indicator, Ng% RPM indicator,
fuel flow indicator, oil pressure gage, and oil temperature gage.
TORQUE INDICATOR
The torque indicator is located on the upper portion of the instrument
panel and indicates the torque being produced by the engine. On some
Cargo Versions, the torque indicator is electrically powered and
operates in conjunction with a transmitter located on the top of the
reduction gearbox front case. The transmitter senses the difference
between the engine torque pressure and the pressure in the engine
case and transmits this data to the torque indicator. The torque
indicator converts this information into an indication of torque in foot-
pounds. The torque indicator system is powered by 28-volt DC power
through a circuit breaker, labeled TRQ IND, on the left sidewall switch
and circuit breaker panel.
On other Cargo Versions and the Passenger Version, the torque
indicator is pressure actuated. Two independent lines enter the back of
the torque indicator. One line measures the engine torque pressure and
one line measures the reduction gearbox internal pressure. The torque
indicator monitors the engine torque pressure and converts this
pressure into an indication of torque in foot-pounds. Instrument
markings indicate that the normal operating range (green arc) is from
0
to 1865 foot-pounds, the alternate power range (striped green arc) is
from 1865 to 1970 foot-pounds, and maximum torque (red line) is 1970
foot-pounds. Maximum takeoff torque is denoted by
"T.O." and a red
wedge at 1865 foot-pounds.
(Continued Next Page)
Revision 23
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