Robinson Helicopter Company RTR 660, Maintenance Manual

Page: 377 / 542

63-11 (Engine Driveline) Forward Flex Plate Shimming (continued)
5. Evaluate flange straightness by calculating the difference between the 3 o’clock positions
in steps 4a and 4b. Also calculate the difference between the 9 o’clock positions in
steps 4a and 4b. If either calculated difference exceeds 0.015 inch, either one or both
flanges are bent and require replacement.
6. Using the smaller average gap from step 4a or 4b, subtract the flex plate average
thickness determined in step 3:
Smaller average gap between flange arms (step 4a or 4b) inch
Subtract flex plate average thickness (step 3) − inch
Total = inch
7. Select shims per Table 63-1 and install forward A947-2 flex plate assembly. Standard
torque nuts and palnuts per Section 20-32 and torque stripe per Figure 5-1. Remove
F642-1 (engine) shaft weldment temporary support.
WARNING
Shim both arms of flanges equally. All fasteners must meet
torque requirements given in Section 20-33.
Calculated
Dimension
Shim required between
forward A947-2 flex plate and
F910-1 (main gearbox) yoke
Shim required between
forward A947-2 flex plate and
F642-1 (engine) shaft weldment
forward flange
−0.041 inch or greater
negative number
NAS1149F0432P washer between aft A947-2 flex plate assembly
and F642-1 (engine) shaft weldment aft flange and/or F018-1
clutch assembly yoke may be relocated under nut as required to
achieve −0.040 / 0.000 inch calculated dimension. Relocate
washers as required, and repeat steps 4 thru 7.
−0.040 / 0.000 inch None None
+0.001 / +0.029 inch NAS1149F0432P washer None
+0.030 / +0.059 inch NAS1149F0432P washer NAS1149F0432P washer
+0.060 / +0.090 inch NAS1149F0463P washer NAS1149F0432P washer
+0.091 / +0.121 inch NAS1149F0463P washer NAS1149F0463P washer
+0.122 inch or greater
positive number
NAS1149F0432P washer between aft A947-2 flex plate assembly
and F642-1 (engine) shaft weldment aft flange and/or F018-1 clutch
assembly yoke may be exchanged with NAS1149F0463P washer
as required to achieve −0.040 / 0.000 inch calculated dimension.
Exchange washers as required, and repeat steps 4 thru 7.
TABLE 63-1 ENGINE DRIVELINE
SEP 2012 R66 Maintenance Manual Chapter 63 Main Rotor Drive System
Page 63.3