CESSNA SECTION
7
MODEL 2086 (675 SHP) AIRPLANE AND SYSTEMS DESCRIPTION
ENGINE
ACCESSORIES
(Continued)
ENGINE GEAR REDUCTION SYSTEM
The reduction gear and ProDeller shaft, located in the front of the
engne, are nou<ed in two' magnes~um alloy castings which are bolted
together at the exhaust outlet. The gearbox contains a two-staae
planetary gear train, three accessory
&ives, and propeller shaft. The
first-stage reduction gear is contained in the rear case, while the
second-stage reduction gear, accessory drives, and propeller shaft are
contained in the front case. Torque from the power turbine is
transmitted to the first-stage reduction gear, from there to the
sewnd-
stage reduction gear, and then to the propeller shaft. The reduction
ratio is from a maximum power turbine speed of 33,000 RPM down to a
propeller speed of 1900 RPM or a reduction ratio of
0.0576:l.
The accessories, located on the front case of the reduction gearbox,
are driven by a bevel gear mounted at the rear of the propeller shaft
thrust bearing assembly. Drive shafts from the bevel drive gear transmit
rotational power to the three pads which are located at the
12,
3 and
9
o'clock positions. Propeller thrust loads are absorbed
by
a flanged ball
bearingassembly located on the front face of the reduction gearbox
center bore. The bevel drive gear
adjust~ng spacer, thrust bearing, and
seal runner are stacked and secured to the propeller shaft by a
dey-
washer and spanner nut.
A
thrust
bearing
cover assembly is secured
by bolts at
thefront flange of the reductiongearbox front case.
CHlP DETECTORS (Optional)
Two chip detectors are installed on the engine, one on tne underside of
the reduction aearbox case and one on the underside of the
accessow
gearbox case. The chip detectors are electrically connected to ah
annunciator, labeled CHlP DETECTOR, on the instrument
an el.
The
annunciator
wrll lllumlnate when metal ch~ps are present in one or both
of the
C~ID
detectors lllumlnatlon of the CHlP DETECTOR annunc aror
necessitates the need for inspection of the engine for abnormal wear.
(Continued Next Page)
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Revision
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U.S. 7-67
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