62-31 Journal and Shim Calculations (continued)
B. Coning Hinge Calculation
1. Measure and record main rotor hub width across the coning hinge
bearing faces: inches
2. Subtract blade’s spindle width measured across faces at coning hinge
bolt bore: – inches
Calculated empty space: =
inches
CAUTION
Initial coning hinge hardware stack-up must be adjusted to
0.007/0.011 inch greater than calculated empty space. A
smaller initial stack-up could damage thrust washers and hub
bearings during installation.
3. To accommodate dimensional change due to clamping force, add: + 0.007/0.011 inch
Sum: = inch
4. Subtract combined measured length of both C106-7 journals to be
installed: – inches
Result: = inch
of C117 shims
5. Preceding Result is initial calculated C117 shim stack required between trailing-edge
journal and thrust washer. Deviate from initial trailing edge shim stack-up as necessary
to meet coning hinge axial play per Figure 62-8 and maintain friction requirements as
follows: It must be possible to manually cone each blade without teetering the hub
when blades are held up off the droop stops and lifted at tip. Increasing shim stack-up
or journal length decreases hinge friction.
C106 Journal Lengths
Part No. Length Location
C106-5 1.775 Teeter hinge (two per hinge)
C106-7 1.284 Coning hinge (two per hinge)
C117 Shim Sizes
Part No. Thickness Location (Between thrust washer and journal)
C117-8 0.012 Teeter hinge; Coning hinge trailing-edge side
C117-9 0.015 Teeter hinge; Coning hinge trailing-edge side
C117-10 0.020 Teeter hinge; Coning hinge trailing-edge side
C117-11 0.025 Teeter hinge; Coning hinge trailing-edge side
TABLE 62-1 HINGE FRICTION JOURNALS AND SHIMS
(Journal length and shim thickness values given in inches)
Page 62.12 Chapter 62 Main Rotor R66 Maintenance Manual 25 OCT 2010
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