62-32 Adjusting Hinge Friction (continued)
B. Coning Hinge Adjustment
Coning hinge friction is adjustable through use of various thickness C117 shims.
Shims are installed between the thrust washer and the trailing-edge journal.
1. Check blade hinge friction by lifting blades until spindle tusks clear droop stops.
Hold one blade level and cone opposite blade. Rotor hub should not teeter as
blade is coned. Repeat check on opposite blade.
2. Refer to Figure 62-8. Using a feeler gage, measure gap between thrust washer
and rotor hub bearing. Gap must be measured on both leading edge & trailing
edge sides of coning hinge and the total must not exceed 0.005 inch (0.003
inch if new hub bearings are installed).
3. Refer to Figure 62-3. Remove cotter pin, nut, and thrust washer from coning
hinge bolt.
4. Refer to Table 62-1. Remove shim(s) to be changed. Measure shim thickness
and select next size thicker or thinner as required. A thicker shim will decrease
blade’s coning hinge friction. A thinner shim will increase blade’s coning hinge
friction and decrease any gap between blade’s thrust washers and hub bearings.
NOTE
When a shim is replaced with a shim of a different size, it will
be necessary to install a new nut and bolt. Drilled holes in
original bolts will not align at required bolt stretch.
5. Replace coning hinge bolt with a new bolt.
6. Install shims, and new bolt and nut, per § 62-10 Part B, steps 4 thru 6.
7. Repeat steps 1 and 2. Drill new bolt and nut per § 62-33; coat new cotter pin
with epoxy primer and install wet. Repeat on opposite blade as required.
62-33 Drilling Nuts and Bolts
New bolts and nuts must be installed and bolts stretched to § 20-32 limits prior to drilling.
Nuts have three blind holes pre-drilled into every other nut flat to be used as drilling guides.
Using a six inch long 0.156-inch diameter Cobalt twist-drill, drill a hole through nut and
bolt using an accessible pre-drilled hole in nut. If a shorter length drill is used, protect
hub from damage due to chuck contact by wrapping chuck and/or covering hub edge with
several layers of tape. Prevent chips from contaminating other mechanisms.
NOTE
If none of the predrilled holes in nut are accessible for use as a
guide after stretching bolt, loosen nut and reposition bolt and
nut. Restretch bolt per § 20-32.
JUL 2020 Chapter 62 Main Rotor Page 62.17
To Next Page
