UH-19 (Series C) Engine Fan Assembly Balance Check

TM 55-4920-201-14

c. Install arbor downward through fan

assembly hub, seating cone in top cone seat of fan

assembly.

d. Install adapter (8, figure 1-14), slotted

hub upward, over lower end of arbor so that its

cone surface engages bottom cone seat of fan

assembly. Install spacers (7, figure 4-31), followed

by hand wheel (26, figure 1-13), on bottom of arbor

and tighten to clamp cones firmly in fan cone seats.

e. Install quick-disconnect coupling (10,

figure 1-13) to arbor suspension rod and hoist

entire assembly approximately inch off work

stand. Check to insure suspended assembly is free

of interference with work stand or adjacent objects,

and note the balance condition indicated by black

indicator disc at top end of the arbor.

f. For balance tolerance and application of

balance corrections, refer to applicable helicopter

manual. (Refer to appendix A).

4-55. UH-19 Engine Fan Assembly Track and

Concentricity Check. (See figure 4-32).

a. Set base (2) on surface plate (1) or other

firm and level support surface. Bolt or clamp base

securely to support surface.

b. Install lower end of balancing arbor (3) in

Engine fan assembly

base (2) pilot hole. Make certain that arbor is

Cone (2228, 7A050 kit)

firmly bottomed and free to rotate in base.

Arbor (2259, 7A050 kit)

Arbor scale

c. Install plate (4), hub downward, on arbor

Cone setscrew

so that bottom of the plate hub clears top of base

Plate (2342, 7HEL055 kit)

(2) by approximately inch. Secure plate in this

Spacer (2202, 2203, &

position by tightening plate setscrew (8) with 1/8

2204, 7A050 kit)

inch hex wrench (8. figure 1-13).

Figure 4-31. Balancer Installation - UH-19

d. Install engine fan assembly 17, figure 4-

Helicopter Engine Fan Assembly.

32), shroud unward. on plate (4). Check to insure

that fan assembly hub pilot diameter seats firmly

4-54. UH-19 (Series C) Engine Fan Assembly

and squarely inside plate pilot lip.

Balance Check. (See figure 4-31).

e. Install cone (5), hub upward, over top of

arbor. Press cone (5) firmly against top of fan

a. Set engine fan assembly (1), hub extension

assembly hub, and secure cone in this position by

downward, central on stand table assembly (1,

tightening cone setscrew (6) with l/8 inch hex

figure 1-13).

wrench (8, figure 1-13).

b. With fan assembly in this position, try

f. Install 1/2 inch mushroom point on dial

alternately fitting cones, part no. 2207 and 2208

indicator (9, figure 4-32), and adjust height gage

(7A050 kit), in top cone seat of fan assembly.

assembly (10) to read track of concentricity

Select cone that fits cone seat and install this cone,

variations as required. Rotate fan and arbor

hub upward, on balancing arbor (3, figure 4-31) so

assembly to determine range of variations.

that its top surface aligns with 11 inch position

on arbor scale (4). Lock cone firmly in this position

g. For track and concentricity tolerances and

with cone setscrews, using 1/8 inch hex wrench (8,

application of corrections, refer to applicable

figure 1-13).

helicopter manual. (Refer to appendix A).

4-52