Piper PA-28-161, Maintenance Manual

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PIPER AIRCRAFT, INC.
PA-28-161, WARRIOR III
MAINTENANCE MANUAL
PAGE 4
Nov 30/06
4F2
55-00-00
B. Balancing Equipment (Refer to Figure 2.)
Balancing must be done using a suitable tool capable of measuring unbalance in inch-pounds from
the centerline of the control surface hinge pin. A suggested configuration is shown in Figure 2.
Other tools may be used if accuracy is maintained and recalibration capability is provided.
To use this tool:
(1) Insure that the control surface is in its final flight configuration, static wicks, trim tabs, trim tab
push pull rod and control surface tip (as applicable) should be installed. The surface should be
painted and trim/servo tabs should be in the neutral position.
NOTE: Because paint is a considerable balance factor, remove existing paint prior to
repainting a control surface.
(2) Place hinge bolts through control surfaces and place control surface on a holding fixture.
(3) Calibrate the tool:
(a) Avoiding rivets, place the balancing tool on the control surface with the tool’s hinge
centerline directly over the hinge line of the control surface.
(b) Adjust the movable trailing edge support to fit the width of the control surface. Tighten the
set screw on the trailing edge support.
(c) Adjust the trailing edge support vertically until the beam is parallel with the control surface
chord line.
(d) Remove the tool from the control surface and balance the tool itself by adding or removing
nuts or washers from the beam balancing bolt. When balancing the tool, the movable
weight must be at the bar’s hinge centerline.
(4) After balancing the tool, reattach it to the control surface. Keep the beam positioned 90° from
the control surface hinge line.
(5) Determine balance of control surface by sliding movable weight along the balance beam.
(6) Read the scale when the bubble in the level has been centered. Multiply by three (3) to
determine inch-pounds (i.e. - since the movable weight weighs three pounds, every inch it is
moved from the center of the beam equals three (3) inch-pounds of force).