67-41 Swashplate Tilting Friction Adjustment
Swashplate tilting friction is established by C197-1 through C197-6 shims controlling
clamping force of Teflon®-lined sleeves on the ball assembly.
1. Mark for reassembly and disconnect boot, pitch links and drive linkage (scissors) from
upper swashplate and both forward push-pull tubes from lower swashplate.
2. Align upper swashplate arms with lateral axis of helicopter and center cyclic stick.
Using MT359-1 spring scale (or equivalent) connected to upper swashplate arm
bolt hole, pull down and note scale reading while swashplate is moving; do not use
breakaway reading. Force required to tilt swashplate must be free-without-looseness
minimum to 5 pounds maximum.
3. To adjust friction, remove outer screws from upper swashplate and raise and secure
retainers to allow access to inner screws on lower, non-rotating swashplate. Remove
inner screws securing sleeve to lower swashplate.
4. Raise sleeve and measure thickness of C197 shim stack. Adjust shim stack thickness
as required to achieve proper tilting friction. Decreasing shim stack thickness increases
tilting friction while increasing spacer stack thickness decreases tilting friction. Install,
and special torque per § 20-33, all inner screws on lower swashplate and at least two
screws thru retainers in upper swashplate prior to measuring tilting friction.
5. Connect both forward push-pull tubes to lower swashplate and standard torque per §
20-32. Install palnut, special torque per § 20-33, and torque stripe per Figure 5-1.
6. Connect both pitch links and drive linkage to upper swashplate (interrupter on same
side as drive linkage) and standard torque per § 20-32. Install palnuts, special torque
per § 20-33, and torque stripe per Figure 5-1.
67-42 Upper and Lower Scissor Assemblies
A. Bearing Removal
C648-2 journal bearings may be removed with a press. Press from inner side of
bearings while supporting outboard side of yoke or fork. Use a socket or other suitable
pressing tool to apply the force.
B. Bearing Installation
1. Clean mating surfaces of A205 fork or C203 yoke where C648 bearing is installed.
Deburr any sharp edges that may damage bearings during installation.
2. Coat yoke or fork bearing bores with zinc chromate or epoxy primer. While primer
is still wet, press in C648-2 bearing while supporting backside of fork or yoke.
MAY 2015 Chapter 67 Flight Controls Page 67.11
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