Textron Cessna Grand Caravan Ex 208B, Pilot'S Operating Handbook And Faa Approved Airplane Flight Manual

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CESSNA SECTION 7
MODEL 208B 867 SHP AIRPLANE AND SYSTEMS DESCRIPTION
GARMIN G1000
U.S.
PROPELLER
The airplane is equipped standard with a Hartzell aluminum material,
three-bladed propeller. The propeller is constant-speed, full-feathering,
reversible, single-acting, governor-regulated propeller. A setting
introduced into the governor with the PROP RPM lever establishes the
propeller speed. The propeller utilizes oil pressure
which opposes the
force of springs and counter-weights to obtain correct pitch for the
engine load. Oil pressure from the propeller governor drives the blades
toward low pitch (increases RPM) while the springs and counterweights
drive the blades toward high pitch (decreasing RPM). The source of oil
pressure for propeller operation is furnished by the engine oil system,
boosted in pressure by the governor gear pump, and supplied to the
propeller hub through the propeller flange.
To feather the propeller blades, the PROP RPM lever on the control
pedestal is placed in the FEATHER position; counterweights and spring
tension will continue to twist the propeller blades through high pitch and
into the streamlined or feathered position. Unfeathering the propeller is
accomplished by positioning the PROP RPM lever forward of the
feather gate. The unfeathering system uses engine oil pressure to force
the propeller out of feather.
Reversed propeller pitch is available for decreasing ground roll during
landing. To accomplish reverse pitch, the power lever is retarded
beyond IDLE and well into the BETA range. Maximum reverse power is
accomplished by retarding the power lever to the MAX REVERSE
position which increases power output from the gas generator and
positions the propeller blades at full reverse pitch. An externally
grooved feedback ring is provided with the propeller.
Motion of the feedback ring is proportional to propeller blade angle, and
is picked up by a carbon block running in the feedback ring. The
relationship between the axial position of the feedback ring and the
propeller blade angle is used to maintain control of blade angle from
idle to full reverse.
CAUTION
The propeller reversing linkage can be damaged if the
power lever is moved aft of the idle position when the
propeller is feathered.
208BPHCUS-00 7-75