Control Surface Balancing - Cessna 177 SERIES Service Manual

GENERAL NOTES
1.
Balance control surfaces in a draft-free area.
2.
Place hinge bolts through control surface hinges and position on knife edge balancing mandrels.
3.
Make sure all control surfaces are in their approved flight configuration: painted (if applicable).
trim tabs installed, balance weight installed, all foreign matter removed from inside of control
surface, stabilator trim tab push-pull rod installed and all tips installed.
4.
Place balancing mandrels on a table or other suitable flat surface.
5.
Adjust trailing edge support to fit control surface being balanced while center of balancing
beam is directly over hinge line.
Remove balancing beam and balance the beam itself by
adding washers or nuts as required at end opposite the trailing edge support.
6.
When positioning balancing beam on control surface. avoid rivets to provide a smooth surface
for the beam and keep the beam 90
°
to the hinge line of the control surface.
7.
Paint is a considerable weight factor. In order to keep balance weight to a minimum, it is
recommended that existing paint be removed before adding paint to a control surface. Increase
in balance weight will also be limited by the amount of space available and clearance with
adjacent parts.
Good workmanship and standard repair practices should not result in unrea-
sonable balance weight.
8.
The approximate amount of weight needed may be determined by taping loose weight at the
balance weight area.
9.
Lighten balance weight by drilling off part of weight.
10.
Make balance weight heavier by fusing bar stock solder to weight after removal from control
surface.
The ailerons should have balance weight increased by ordering additional weight and
gang channel, listed in applicable Parts Catalogs and installing next to existing inboard weight
the minimum length necessary for correct balance, except that a length which contains at least
two attaching screws must be used. If necessary, lighten new weight and/or existing weights
for correct balance.
BALANCING BEAM
Mark graduations in inches
Four-foot length of extruded channel
Grind weight to slide along beam and mark
center of weight. Weight must be exactly
one pound for all surfaces except stabilator
which must be four pounds.
\< ' /Fabricate
vertically adjustable
which must *eIfour poundsk / ^trailing edge support that will
slide along beam. (Refer to Sheet
4 for stabilator support.)
-^
'
~
Attach knife edges
g / -
to beam at mid point -
and mark center.
Figure 18-3. Control Surface Balancing (Sheet 1 of 4)
Change 7 18-9