n. Using dry 80-grit sandpaper on a power sander or sanding block, smooth patch and blend with surrounding
surface. Should air pockets appear while sanding, puncture and fill with catalyzed resin. A hypodermic needle
may be used to fill cavities. Let cure and resand.
o. Mix catalyzed resin and work into patch with fingers. Smooth carefully and work into any crevices
p. Cover with cellophane and squeegee smooth. Allow to cure completely before removing cellophane. Let
cure and resand.
q. Brush or spray a coat of catalyzed resin to seal patch. Sand patch, finish by priming, sanding and applying
color coat
—NOTE—
Brush and hands may be cleaned in solvents such as acetone or methylethylketone.
If solvents are not available, a strong solution of detergent and water may be used.
4-54. CHECKING CONTROL SURFACE FREE PLAY.
The following checks are recommended before balancing to ascertain the amount of "free play" in the
stabilator, stabilator trim tab and aileron:
a. Stabilator: Check the stabilator for any "free play" at its attachment points by grasping each half near the
tip and gently trying to move it up and down, fore and aft, and in and out. NO play is allowed.
b. Stabilator Trim Tab: Set the stabilator trim tab in neutral position. This neutral position is determined
with the airplane properly rigged per instructions given in Section V of this Service Manual and the trim indicator
at its neutral position. Obtain a straightedge long enough to extend from the ground up to a few inches above the
trim tab trailing edge. Place the straightedge next to the trim tab inboard (center) trailing edge; secure the
stabilator in neutral and grasping the tab gently move it up and down; mark the limits of tab free play on the
straightedge. The overall travel (free play) must not exceed 0.15 of an inch. The use of a dial indicator and fixed
stand is recommended.
c. Aileron: Set the aileron in its neutral position and secure the control wheel. Obtain a straightedge long
enough to extend from the ground up to a few inches above the aileron trailing edge. Place the straightedge next
to the aileron trailing edge at the actuator location and gently move the aileron up and down; mark the limits of
travel (free play) on the straightedge. The overall travel (free play) must not exceed 0.24 of an inch.
Should free play exceed the limits stated, make the necessary repairs required to eliminate excessive
free play.
4-55. CONTROL SURFACE BALANCING.
TABLE IV-I BALANCE SPECIFICATIONS
Maximum Limits - Flight Conditions
STATIC BALANCE LIMlTS (In-Lbs)
HEAVY SIDE
HEAVY SIDE
SURFACE
Leading Edge
Trailing Edge
Aileron
0
to
-25
Stabilator
+5
to
-40
Rudder
0
to
-13
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
STRUCTURES
1F7
Issued: FEBRUARY. 28, 1989