25 OCT 2010 R66 Maintenance Manual Chapter 62 Main Rotor Page 62.11
62-30 Main Rotor Assembly
62-31 Journal and Shim Calculations
Refer to Figures 62-2 and 62-3.
A. Teeter Hinge Calculation
1. Measure main rotor hub width across the teeter hinge bearing faces: inches
2. Subtract measured width of C251 driveshaft at teeter hinge bolt hole: – inches
Calculated empty space: = inches
3. Use one C106-5 journal and a selection of C117 shims to create a combined length of
approximately 1.835 inches. Use as many different size shims as possible. Place thrust
washer, shims, and journal under teeter bolt head; shims must be placed between thrust
washer and journal.
Subtract combined measured thickness of selected journal and shims: – inches
Difference: = inches
4. Subtract measured length of C106-5 journal to be used on nut-side: – inches
Difference: = inches
CAUTION
Initial teeter hinge hardware stack-up must be adjusted to
0.005/0.008 inch greater than calculated empty space. A
smaller initial stack-up could damage thrust washers and hub
bearings during installation.
5. To accommodate dimensional change due to clamping force, add: +
0.005/0.008 inch
Result: = inch
of C117 shims
6. Preceding Result is initial calculated C117 shim stack between nut-side journal and
thrust washer. Use as many different size shims as possible to facilitate head shifting
during balancing. Deviate from initial shim stack as required to meet teeter hinge
friction requirements (8-12 pounds is ideal).
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