Rockwell Commander 112 - Propeller Governor; Propeller Governor Removal; Propeller Installation

ROCKWELL
COMMANDER
112/B/TC/TCA
MAINTENANCE MANUAL
SECTION IV
POWER PLANT
AND PROPELLER
gocony Oil Co.
5. Stroma HT -1 (Z-801)
Union
Oil Co.
PROPELLER INSTALLATION
a. Clean engine flange.
b.
Clean propeller hub mounting flange and inspect
mating surfaces for nicks and scratches.
c. Install aft spinner bulkhead to propeller using
existing propeller bolts, nuts, washers and spacers.
Torque nuts to 20-24 foot-pounds.
d. Mate propeller mounting flange to engine flange
and install studs.
e. Install propeller on engine and torque nuts to
60 to 70 foot-pounds and safety wire.
f. Temporarily install forward spinner bulkhead
on propeller dome. The four attaching holes in for-
ward bulkhead are slotted for adjustment. Align two
slots as closely as possible with centerline of pro-
peller blades. Choose two holes that allow maximum
adjustment in both directions.
g. Install attaching bolts to forward spinner bulk-
head, snugly, yet allow for movement of bulkhead
for alignment. It may be necessary to use up to three
washers on some bolts as hole depths vary.
h. Before installing spinner on bulkheads, protect
propeller blades by covering with heavy paper and
wrapping with masking tape. Do not place tape di-
rectly on propeller blade finish.
i. Install spinner on bulkheads. Align holes at
rear of spinne r with holes in aft bulkhead and install
several screws. Rotate forward bulkhead as neces-
sary to align holes with forward holes in spinner. If
necessary, use wooden dowel or similar tool for
ease of alignment.
j. Carefully remove spinner.
k. Torque bolts installed in step g. , to 50 to 70
inch-pounds and safety wire.
1. Install spinner and torque screws to 20 to 25
inch-pounds.
LOW PITCH (HIGH RPM) STOP ADJUSTMENT
a. Remove spinner from propeller. See proce-
dures under propeller removal.
b. Remove forward bulkhead assembly. See
Figure 4-13.
c. Loosen elastic stop nut in the center and on
the front of propeller cylinder.
d. Rotate blades to degrees low pitch as
shown in Figure 4-14.
e. Adjust low pitch setting stop bolt in center of
propeller cylinder to maintain degrees shown in
Figure 4-14 at the 30-inch station on propeller
blade. See Figure 4-15.
f. Tighten elastic stop nut.
g. Install spinner bulkhead and spinner in accord-
ance with propeller installation instructions.
BLADE ANGLE DIFFERENCE CHECK
a. Remove spinner from propeller. See proce-
dures under propeller removal.
Change 3
b. Measure 30 inches out from center of propeller
hub and mark each blade.
c. Set propeller protractor to zero reference
plane by placing it on top center of propeller cylinder
(see Figure 4-15).
d. Place blades in a low pitch position.
e. Check the angle of each blade at the 30-inch
station. Blade must be horizontal and protractor
reading taken on aft side of blade.
f. If the blade angle difference is more than 0.2
degrees between the blades, one of the pitch change
blocks must be rotated to bring the blades into the
0.2 degrees tolerance.
1101.
This means the hub must be disassem-
bled, and therefore, the propeller must
be returned to the manufacturer or
nearest approved overhaul shop.
PROPELLER GOVERNOR
The propeller governor is a single-acting, centrifugal
type, which boosts oil pressure from the engine and
directs it to the propeller where the oil is used to
increase high pitch blade angle (low rpm). High pitch
blade angle is 30 degrees at the 30-inch station on
propeller. A single- acting governor uses oil pres-
sure to effect a pitch change in one direction only; a
pitch change in the opposite direction results from
a combination of centrifugal twisting moment of
rotating blades and compressed springs. Oil pressure
is boosted in the governor by a gear type oil pump. A
pilot valve, flyweights, and a speeder-spring act to-
gether to open and close governor oil passages as
required to maintain a constant engine speed. When
trouble shooting the propeller-governor combination,
it is recommended that a governor known to be in
good condition be installed to check whether the pro-
peller or the governor is at fault. Removal and re-
placement, rigging, high- speed stop adjustment, de-
sludging, and replacement of the governor mounting I
gasket are not major repairs and may be accomplished
in the field. Repairs to propeller governors are
classed as propeller major repairs in Federal Avia-
tion Regulations which also define who may accom-
plish such repairs.
NOI.
Outward physical appearance of specific
governors is the same, but internal parts
determine wheter oil pressure is use to
increase or decrease blade pitch. Always
be certain to use the correct governor.
PROPELLER GOVERNOR REMOVAL
a. Remove upper engine cowling.
b.
Disconnect governor control linkage at governor.
4-29
Copyright Commander Owners Group 2013 All Rights Reserved
**unofficial copy**