Aerovent IM-171 User Manual

Adjustable pitch propeller taper-lock hub, Im-171, Reversible propeller

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Assembly Procedures

1. Lay hub on a horizontal surface with openings of

shank sockets (Fig. 3) facing up. This is normally

the discharge side of the assembly.

2. Lay blade shank in socket with discharge side of

the blade up. The discharge side of the blade is

the side with the angle setting mark. Line up the

index mark on the blade with the proper angle

mark on the end of the shank socket (Figs. 2 and

4) on the underside of assembly.

3. Place cap over blade shank with beveled end

toward center. Install U-bolts and elastic nut stops.

Before tightening lock nuts, pull the blade outward

to set the key against the keyway and check angle

setting (Fig. 3).

4. Tighten elastic stop nuts evenly and torque to the

following foot-pounds:

PROPELLER

HUB

U-BOLT

TORQUE

DIA.

DIA.

SIZE

(FT/LBS)

54" – 72"

14"

1/2"

20

81" – 96"

18"

3/4"

45

5. Check angle setting to be sure it has not changed

during assembly. If so, loosen lock nuts and reset

angle. Tighten nuts again to proper torque. Do not

over-tighten. Be sure to tighten U-bolts evenly.

Setting Angle With Protractor (optional)

Under most conditions, the preceding assembly pro-

cedure using the index marks is of sufficient accu-

racy. When greater accuracy is desired, use a level

bubble protractor. Before the final tightening of the

nuts, set the protractor on the angle setting mark.

(The hub and blade assembly must be level for accu-

rate setting.) Adjust the angle by tapping the shank

end with a mallet. Tighten lock nuts to proper torque.

Again check the angle setting. Rotate propeller to

check angle on each blade in the same location.

Propellers may be assembled so the cap side of

the hub is the inlet side (reverse bore). If blades do

not have the index mark on the discharge side, it is

then necessary to adjust the blade angle with a pro-

tractor.

The hub and blades are balanced separately. The

weight distribution throughout the length of the blade

varies slightly. Therefore, the balance is to a constant

moment and blades may be assembled at random

even though the weights are slightly different.

Adjustable Pitch Propeller Taper-Lock Hub

Reversible Propeller

©1997 Aerovent

Cap and U-Bolt Side

Lock Nut Side

Angle setting index on shank socket. Marked

from 10° through 50°. Each mark is 2°.

Elastic Stop Nuts

Index Marks

Blade

U-Bolts

Cap

Blade

Shank

Hub

Fig. 1

Fig. 2

Fig. 3

General Installation, Operation and Maintenance Instructions For Aerovent Products

IM-171

June 1997

®

Fig. 4

Angle

Setting

Mark

Index

Mark

Inlet Side

Discharge Side

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