Control Surface Balancin; 1G5; Balancing Definitions; Aileron Balancing Procedure (Aileron P/N 40200-00. 40200-01 And 40200-37) - Piper Navajo PA-31 Service Manual

PIPER NAVAJO SERVICE MANUAL
4-85. CONTROL SURFACE BALANCING. The movable control surfaces have been statically balanced at
the time of installation at the factory and normally need not be rebalanced unless the surfaces have been
repainted, repaired or replaced. When rebalancing, surfaces must be removed from the aircraft and placed
on a balance jig. Each control surface must be complete including paint, tab where required, balance
weights, static wicks, torque tubes and horns, etc. Tabs must be held in neutral position with a small piece
of tape. Tab actuating rods must be in place and connected to the tab with the exception of elevator
balancing when wing nacelle lockers are installed, in which case the elevator tab actuating rod shall be
removed. The tab actuating rods must be positioned to correspond to the neutral tab position. The
balancing must be accomplished in a draft free area and in a manner to allow unrestricted movement of the
control surface.
4-86. BALANCING EQUIPMENT. The balancing must be done using a suitable tool configuration as
shown in Figures 4-15 and 4-16.
4-87. BALANCING DEFINITIONS. The following is a list of balancing definitions as used in this service
manual:
a.
Master Test Weight: A fabricated tool temporarily attached to the control surface to determine
when the surface is at its lower static balance limit.
b. Balance Weight: Weight attached permanently to a control surface to produce a static hinge
moment within the required range (such as 40 inch-pounds ± 10 inch-pounds trailing edge heavy).
c.
Trailing Edge Heavy: Positive static hinge moment; trailing edge of the surface moves downward
when released from a neutral position.
d. Leading Edge Heavy: Negative static hinge moment; leading edge of the surface moves downward
when released from a neutral position.
e. Master Test Weight Arm: Perpendicular distance between the control surface hinge line and the
point of application of the test weight.
f. 0. 1 Pound (+0 -.04 oz.) Test Weight: Small weight added to the master test weight or used alone
during the balancing procedure to determine if the surface is below the upper static balance limit.
g. Tm Weight: Small weight added permanently to the surface balance weight to bring it within
tolerances. (Sometimes required depending on variations in surface construction.)
4-88. AILERON BALANCING PROCEDURE. (Aileron P/N 40200-00. 40200-01 and 40200-37.)
a.
Remove the aileron from the aircraft and place it on a balance jig. (Refer to Paragraphs 4-15,
4-85, 4-86 and Figure 4-15, View A.)
b. Fabricate a master test weight (See Table IV-I) and hang it from the aileron balance weight
forward attachment bolt. The surface should balance so the trailing edge lines up with the level reference line
scribed on the jig.
c. If the surface balances with just the test weight, it is at the minimum balance limit and is
satisfactory.
d. If the aileron is leading edge heavy with the master test weight installed, material must be
removed from the surface balance weight until a balanced condition is obtained. This would also result in
the lower static balance limit.
e. If the aileron is trailing edge heavy with the master test weight installed, it must be determined
that the aileron does not exceed the upper static limits from Table IV-I. Add individual 0.1 lb. test weights
to the master test weight until the aileron balances. If the number 0.1 lb. test weights does not exceed the
maximum allowable from Table IV-I, the aileron is within the static limits and is satisfactory. If the number
of 0.1 lb. test weights added to the master test weight to balance the aileron exceeds the maximum
allowable from Table IV-I, the aileron balance exceeds static limits. The reason for the excessive unbalance
must be determined, the unbalance must be corrected, and the aileron re-checked.
Revised: 9/24/81
STRUCTURES
1G5