Piper PA-24 Comanche Service Manual page 345

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PIPER COMANCHE SERVICE MANUAL
e. ."ount propeller on engine. Screw each stud (7) intO its matinl
f1&n~
bushill,
I
few threads at
I
time until all are tight. Torque bola to specifications given
in Table VllA·1. SafetY the mounting bola with
."S20995C"1 wire. routing the wire through the lock pills (8).
f.
Check blade track per p&rllf&ph 7 A-22.
g. Check low pitch blade &nile. (Refer to parqraph 7A·Zl.)
h. Install engine cowling if removed.
I. Install spinner (1) and secure with screws.
7A-2L Adjustment
Of Low Pitch
BI.x ADtlc Stop.
I.
The propeUcr comes from the factory with the low pitch stOp adjusted for proper blade angle. If.
however. this adjustment has bccn dimarbed. the foUowin, procedure is pen for obtaininJ blade angle:
1. The blade ansle (Refer to Table VlIA-1)
is
dcurmined by placing a propeller protractor on the
face side of the propeller. at the 30 inch sation.
u
measured from the hub center line. The blade must be
horizontal. .
2. The low pitch nop adjustment is made by a screw in the nose of the propeller eylinder.
Roatmg the screw clockwise increases the low pitch and reduces the
scarie
RPM by about 100 RPM for
each half cum; or vice versa.
b. After the low Ditch stop hu been adjusted for proper blade qie. the govemor should then be
adjusted to obtain
max~um
rated e . e RPM durin, take-off and climb u dcscnbcd
ui
para,raph 7A·27.
7.-\-22. Blade Track. Blade luck is the ability of olle blade tip
to
foUow the other. while rotaring. in
almost the sante plane. Exceuive difference in blade track· more than .0625 inch· fRay be an indication of
bent blades or Improper propeller installation. Check blade traCk as foUows:
a. With the enr'ne shut down and blades Yertical. secure to the aircraft a smooth board
JUSt
under the
tip of the lowe: blade .."'oYe the tip fore and aft through itS full "blade1hake" mvel. makmg small marks
WIth
1
pencil at each position. Then centct the tip betwccn these marks and scribe a line on the board for
the fuil width of the tip.
b. Carefully rotate propeller by hand to bring the opposite blade down. Center the tip and scribe a
pencil line as before lnd check that lines arc not separated more than
.062'
inch.
c. Propellers haVIng excess blade track should be removed and inspected for bent blades or for parts
of sheared "0" nng. or foretln panicles. which haye lodged betWccn hub and crankshaft mounting faces.
Bent blades will require rcpw and overhaul of assembly.
POWER PLANT
ISSUED: 8/18/72
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