TAIL ROTOR BALANCING KIT 7HEL051 - TM-55-4920-201-140065

TM 55-4920-201-14

Do not use solvent near open flame or in

3-21. TAIL ROTOR BALANCING KIT

area where very high temperatures prevail.

7HEL051. (See figure 1-16.)

CAUTION

3-22. Unpacking. Releasing the trunk-type latches

and raising the hinged top will expose the com-

In handling the small arbor, particular

ponents of this kit. Upon raising the hinged cover,

care shall be exercised to avoid all

visually examine the large adapter assembly to.

impact or excessive downward pressure

made sure the eight phenolic blocks and the

on the suspension rod.

remainder of the kit components are undamaged.

a. Carefully clean all residual oil and

3-23. Handling. Exercise care in the handling and

preservative compound from the arbor assembly

use of the adapter assembly because of the

using solvent, Specification P-D-680, or equivalent.

susceptibility of damage and breakage of the

b. As shipped, the top end of the small arbor is

phenolic positioning blocks. Avoid careless or

sealed by an internal, spring-loaded seal located on

indifferent handling of any part.

the suspension rod under the indicator bushing. In

3-24. TAIL ROTOR AND FAN BALANCING

addition to preventing loss of dash-pot oil, this seal

KIT 7HEL052. (See figure 1-17.)

also supports the suspension rod in a fixed position

3-25. Unpacking. As with the TA050 and 7A052

in the arbor during shipment. To unseal the spring

kit shipping cases, the 7HEL052 shipping box is

loaded seal and free the suspension rod for normal

normallybanded prior to shipment. If used, cut the

operation, push the indicator bushing downward,

metal bands and remove nails securing the single

against light spring tension, so that its bottom

piece plywood top. Lift out the kit storage case and

surface clears the black indicator disc by ap-

store the shipping box for possible future use.

proximately 0.003 inch. (For use of paper spacing

3-26. Handling. Releasing the trunk-type latches

shims, see figure 3-5). Lock indicator bushing in

and raising the hinged top exposes the contents of

this position with indicator bushing set screw, using

this kit consisting of a large crisscrossed type of

hex wrench provided in the 7HEL053 kit. Remove

adapter assembly, cones and sleeves. The adapter

paper shims and check to insure indicator bushing

assembly incorporates a phenolic block at the end

moves freely.

of each leg. Make sure the blocks are undamaged

NOTE

and handle the adapter assembly with care to avoid

Review paragraph 3-8 for care and

possible future damage. The adapter hub, the cones

precautions to be observed when handling

and sleeves shall be protected from accidental

balancing arbor assemblies.

nicks, scratches. burrs or other detrimental

3-31. MAIN ROTOR BALANCING

KIT

discrepancies.

7HEL054. (See figure 1-19.)

3-27. SMALL PARTS BALANCING KIT

3-32. Unpacking. Accessibility is gained to all

7HEL053. (See figure 1-18.)

components of this kit after the releasing of latches

3-28. Unpacking. Releasing the two trunk-type

and raising of the hinged cover. All kit details are

latches and raising the hinged cover provides access

adequately preserved and securely recessed into

to all components of this kit. Since the kit details

appropriate compartments of the storage case.

provide for a multitude of applications, to minimize

3-33. Handling. Many of the kit components are

loss and possible damage, it is suggested only those

factory balanced and all are precision finished.

parts actually required for the specific balance

Exercise extreme care in handling and usage of the

application involved be removed from the storage

parts. Nicks, scratches, burrs, raised edges and

case. The packing layout glued to the inside of the

contamination shall be avoided. Store parts in the

top cover will help identify and locate parts. All

kit case when not in use.

parts shall be returned to their proper locations in

the storage case after use and preservation.

3-34. FAN TRACK AND CONCENTRICITY

3-29. SMALL BALANCING ARBOR, PAR?'

CHECKING KIT 7HEL055. (See figure 1-20.)

NO. 2516.

Releasing the trunk-type latches and raising

3-30. Remove small balancing arbor (22, figure 1-

the hinged top cover provides accessibility to the

18) from its cradle in the kit storage case by lifting

three components of this kit as identified by the

the exposed end of the arbor and carefully pulling it

packing layout on the inside of the cover. Both the

out of the tilting support tube. Preparation of this

plate and adapter are precision machined and

arbor for use differs from that of the larger Part no.

balanced at the factory and care shall be taken to

2259 arbor as explained below.

protect these parts from damage. The indicator

WARNING

assembly shall be handled as any other precision

Cleaning may be toxic. Use in well-

gage and shall not be immersed in any solvent or

ventilated area. Avoid prolonged inhala-

other fluids.

tion of fumes or direct contact with skin.

Change 1 3-11