PIPER AIRCRAFT, INC.
PA-28-161, WARRIOR III
MAINTENANCE MANUAL
PAGE 5
Nov 30/064H15
57-50-00
2. Control Surface Balancing
A. Checking Free Play
(1) Set the aileron in its neutral position and secure.
(2) Obtain a straightedge long enough to extend from the ground up to a few inches above the
aileron trailing edge.
(3) Place the straightedge next to the aileron trailing edge and gently move the aileron up and
down, mark the limit of travel (free play) on the straightedge.
(4) The overall travel (free play) must not exceed 0.24 of an inch. Should free play exceed the limit
stated make necessary repairs as required to eliminate free play.
(5) Grasp the aileron and move it spanwise (inboard/outboard) to insure maximum end play of
0.035 of an inch is not exceeded.
B. Balancing Equipment
Balancing must be done using a suitable tool capable of measuring unbalance in inch-pounds from
the centerline of the control surface hinge pin. See the tool configuration in Figure 4. Other tool
configurations 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.
NO
TE: Because paint is a considerable balance factor, it is recommended that existing paint
be removed 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 per Figures 2 and 4. 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 level has been centered. Multiply by three to determine inch-
lbs. (I.E. - Since the movable weight weighs three pounds, every inch it is moved from the
center of the beam equals three inch-lbs of force.)
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