Piper Navajo PA-31 Service Manual page 158

PIPER NAVAJO SERVICE MANUAL
156 B
TAPE TRIM TAB LEVEL
WITH RUDDER
JIG KNIFE EDGE
LEVEL
RUDDER BALANCE JIG
10 LBS. (-O -.04 OZ.) TEST WEIGHT
RUDDER ASSEMBLIES MASTER TEST WEIGHT
40046-00
MASTER TEST WEIGHT ARM
40046-26
40046-39
Figure 4-21. Rudder Balancing
a.
Remove the rudder from the airplane. (Refer to Paragraph 4-37.)
b. Place the rudder horizontally on the balance jig. (Refer to Paragraphs 4-85 and .4-86.)
c.
Fabricate a master test weight per specifications given in Table IV-I and hang it in the existing
tool hole in the rudder counterbalance channel. Ascertain that the tool hole is located to provide the proper
master test weight arm as shown in Figure 4-21. defined in Paragraph 4-87 and specified in Table IV-I.
d.
If the rudder balances with just the specified master test weight, the surface is at the minimum
static limit per Table IV-I and is satisfactory.
e.
If the rudder is leading edge heavy with the master test weight installed, trim weights (if installed)
and/or material from the surface balance weight must be removed until a balanced condition is obtained.
This would also result in the lower static limit.
f.
If the rudder is trailing edge heavy with the master test weight installed, it must be determined
that the rudder does not exceed the maximum static limits per Table IV-I. Add individual 0.1 pound test
weights to the master test weight until the rudder balances. If the number of 0.1 pound test weights added
does not exceed the maximum allowable per Table IV-I, the rudder is within the static limits. If the number
of 0.1 pound test weights added to the master test weight to balance the rudder exceeds the maximum
allowable per Table IV-I, the rudder balance exceeds the static limit and trim weights must be added to the
rudder according to the following procedure:
Revised: 9/24/81 STRUCTURES
IG14