62-10 Main Rotor Blades (continued)
B. Installation (continued)
CAUTION
To prevent damage, level and support installed blade until
opposite blade is installed.
6. With installed blade level and supported near tip, install opposite blade per steps 1 thru 5.
7. Tighten nut on hinge bolt until journals and thrust washer are firmly seated. Then
back nut off until both thrust washers can be freely rotated.
8. Install MT122-6 main rotor bolt stretch tool on hinge bolt per Figure 62-4. Zero dial
indicator by rotating dial face. Lock dial and remove tool.
9. Using wrenches with at least 600 ft-lb torque capacity, tighten nut until drilled hole in
nut and bolt align. Reinstall MT122-6 tool and measure bolt stretch; the stretch must
be between 0.020 - 0.022 inch (0.021 - 0.022 inch for new, undrilled bolt). Remove
tool. Install a new cotter pin with wet epoxy primer.
NOTE
If drilled holes in nut and bolt do not align, both nut and bolt
must be replaced. Stretch new bolts per § 20-33; drill new nuts
and bolts per § 62-33.
WARNING
The main rotor blade and hub attach bolts must be stretched
from 0.020 - 0.022 inch (0.021 - 0.022 inch for new, undrilled
bolt) to obtain proper clamping force. Under-stretching or over-
stretching can cause catastrophic failure of the bolts.
10. Connect pitch link to pitch horn. Standard torque per § 20-32, install palnut, and
torque stripe per Figure 5-1.
11. Repeat steps 1 thru 10 for remaining blade. If installed main rotor blade pitch bearing
housing has recently been serviced (including new or overhauled blades), perform
steps 12 thru 16.
12. Position cyclic and collective at approximately mid-travel positions to minimize wrinkles
in boots.
13. Insert two (2) MT549-1 spacers between hub and boot with gaps at top and bottom.
Spacers should fit in recess of boot. Hold spacers in place against boot and insert
MT549-2 plate from top between hub and spacers. Push plate down until it contacts
spindle.
14. Remove lower plug from pitch horn and allow oil to flow. Place a finger over hole as
soon as oil flow decreases to a drip to prevent air from being sucked inside blade.
15. Remove finger from hole and quickly install drain plug. Special torque per § 20-33 and
torque stripe per Figure 5-1.
16. Remove plate and spacers. Repeat on second blade.
MAY 2015 Chapter 62 Main Rotor Page 62.5
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