Rudder Balancing Procedure - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
NOTES
1. Do not exceed 60 pound force for any measurement.
2.
The elevator shall be rotated with a steady movement and the
force reading taken when the elevator is passing through the
neutral position. Do not stop rotation when taking the
reading.
4-97. RUDDER BALANCING PROCEDURE.
(Refer to Figure 4-19.)
PPS-50022
a. Remove the rudder from the airplane. (Refer to Paragraphs 4-37, 4-91 and 4-92.)
b.
Place the rudder horizontally on the balance jig.
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, part number 40045. Ascertain that the tool hole is located to
provide the proper master test weight arm as shown in Figure 4-19, defined in Paragraph 4-93 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 limits 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)
or material must be removed from the surface balance weight 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.
g.
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.
h. 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 limits and trim
weights must be added to the rudder to produce a balanced condition. (Refer to Table IV-I for the trim
weight part number and the maximum amount allowed for the particular rudder assembly being balanced.)
NOTE
During this procedure, the master test weight must carry no more
than the maximum number of 0.1 pound test weights as called out
in Table IV-I.
i. For rudder assemblies, part number 40046-30, the following procedure should be used to install
trim weights:
NOTE
The tab acuating rod must be disconnected when balancing rudder
assembly P/N 40046-30.
1.
Remove the rudder tip by removing attaching screws.
2. A trim weight attachment point is provided and located in the web of the upper rib,
approximately .62 of an inch aft of the primary balance weight. (Refer to Figure 4-20.)
3. Trim weights are installed with AN3-A bolts with the length depending on the amount of
trim weights used.
4. Install the rudder tip and secure with attaching screws.
j. For rudder assemblies, part number 40046-34 or 40046-38, the trim weights are mounted below the
rudder to support channel. (Refer to Figure 4-20.)
k. With rudder completely reassembled, recheck the balance to insure that it is now within the
proper limits.
1. Reinstall the rudder per Paragraph 4-38.
Revised: 3/11/81
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STRUCTURES