OH-58 Series Tail Rotor Hub and Blade Assemblies Balance Check

TM 55-4920-201-14

Key to figure 4-23:

Clamp section, 3035 lock

Ring nut, 3035 lock

Bushing (2777, 7HEL069

1. Stand table (7A050)

2. Fixture (2337, 7HEL054)

Yoke (2780, 7HEL069)

3. Adapter (2775,

10.

Arbor (2259, 7A050)

7HEL069)

11.

Set screws, 2780 yoke

12.

Set screw, 2777 bushing

4. Lock (3035, 7HEL069)

(2)

13.

Handwheel (2215,

5. Ring nut. 3035 Lock

7A050)

4-41. OH-58 Series Tail Rotor Hub and Blade

h. Install arbor, with bushing, downward

Assemblies Balance Check. (See figure 4-24.)

thru plate on rotor hub, adapter and fixture. Seat

tightly against plate and rotor hub. Tighten 2 lower

a. Assemble 7A050 work stand and hoist

support structure as shown in figure 3-3.

set screws 19) of fixture hub evenly to maintain

clamping pressure.

b. Place fixture (2), recessed side downward,

centrally on work stand table (1).

i. Position rotor assembly and adjust blade

pitch to locate pitch horn studs ( 10) adjacent to

c. Assemble spacer (13) to threaded end of

post assemblies (3) below their indexing pin sec-

two post assemblies (3). Install assembled units

tions (12). Rotate upper section (11) of posts to

into tapped holes A, view A, of fixture (2). Use

position knurled length of index pin (12) above

fingers only to tighten.

pitch horn studs. Readjust pitch of blades to seat

d. Place adapter (4), large end downward,

studs upward against extending index pin knurled

over hub extension of fixture (2).

section, see view B, of figure 4-24.

e. Position tail rotor assembly to place static

j. Attach 2266 quick disconnect coupling

stop (machined) surface of yoke section upward

with 2264 cable (7A050 kit) to 2516 arbor.

and index to locate trunnion bearing restrictions

Engage cable ball into lifting plate of stand hoist.

adjacent to flat sides of adapter. Engage trunnion

k. Hoist assembly approximately inch

bore with pilot diameter and install to seat upon

above stand table; stabilize movements, and ob-

adapter shoulder (4).

serve balance indicated by black disc in top surface

f. Place plate (5) centrally (accessory part

of arbor shaft. Check to insure balance indications

P / N 2586 may be substituted) on top surface of

are not affected by interferences from the stand, air

rotor hub.

drafts or movement of nearby personnel.

g. Install bushing (6) on arbor (7) with its

l. For balance tolerances, method of

flanged end downward. Position to align its top

correction and other assembly requirements, refer

surface (sensitivity setting reference) with the 8--

to applicable helicopter maintenance manual.

inch arbor scale location for rotors incorporating

flyweight ring type pitch horns or 9--inch location

for non-weighted horns. Secure by tightening the

two bushing set screws (8) evenly.

Change 6 4-39