Aerovent IM-170 User Manual

IM-170

June 1997

General Installation, Operation and Maintenance Instructions For Aerovent Products

Adjustable Pitch Propeller Taper-Lock Hub

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).

PROPELLER HUB U-BOLT TORQUE (FT/LBS)
DIA. DIA. SIZE ALUMINUM FIBERGLASS
54" – 72" 14" 1/2" 20 30

81" – 144 18" 3/4" 45 50

4. Tighten elastic stop nuts evenly and torque to the
following foot-pounds:

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 proce­dure using the index marks is of sufficient accuracy.
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 accurate 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 protractor.
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. Blades
are marked for size and rotation (Fig. 4). “54 R” means
a 54" diameter fan with right-hand rotation.

Fig. 1

Cap and U-Bolt Side Lock Nut Side

Fig. 2

Angle setting index on shank socket. Marked from 10° through 50°. Each
mark is 2°. When hub is viewed as shown above, scale on left side
should be used for right-hand propeller and scale on right side should
be used for left-handed propellers.

Fig. 3

Blade

Shank

Hub

U-Bolts

Cap

Key

Index Marks

Keyway

Elastic Stop Nuts

Blade

Fig. 4

Trailing

Edge

Blade Size

and Rotation

Index
Mark

Angle
Setting
Mark

Inlet Side Discharge Side

©2005 Aerovent

Right-hand or left-hand rotation of propellers is determined as follows: When facing into the discharge of
the fan, clockwise rotation is right-hand; counterclockwise rotation is left-hand. The thicker rounded edge of the
blade or edge opposite the pointed tip is the leading edge.

Installation Instructions For Propellers Equipped With

Browning Malleable Iron Split Taper Bushings

Aerovent adjustable pitch propellers are furnished with
hubs that have a tapered bore. A split taper bushing is
used for mounting the propeller assembly to the shaft.
When properly assembled, the bushing grips the hub
and the shaft with a positive clamping action. The split
taper bushing is always mounted on the discharge or
cap side of the hub unless the propeller has been
ordered with a reverse bore.

A. Bushing barrel and bore of propeller hub are

tapered. This assures concentric mounting and a
true running propeller.

B. Capscrews, when tightened, lock bushing in propel-

ler. Use plated capscrews threaded full length (see
table below).

BUSH CAPSCREW TORQUE
NO. SIZE THREADS/IN LENGTH (FT/LBS)
Q2

R2

3

∕8" 16 21∕2" 24

3

∕8" 16 3" 24

C. Bushing is split so that when the locking capscrews

force bushing into tapered bore, the bushing grips
the shaft with a positive clamping fit. This will with­stand vibration and punishing loads without being
loosened.

D. Propeller and bushing assembly is keyed to shaft

and held in place by compression. This gives added
driving strength.

Installation Instructions

Put bushing loosely into propeller. Do not press or
drive. Start capscrews by hand, turning them just
enough to engage threads in tapped holes on propel­ler. Do not use a wrench at this time. The bushing
should be loose enough in the propeller to move
slightly.
Be sure shaft and keyway are clean and smooth.
Check key size with both shaft and bushing keyways.
Slide propeller and bushing assembly onto shaft, mak­ing allowance for end play of shaft to prevent rubbing.
Do not force propeller and bushing onto shaft. If it
does not go on easily, check shaft, bushing and key
sizes.
Tighten capscrews progressively with wrench. Do
this evenly as in mounting an automobile wheel. Take
a part turn on each capscrew successively until all are
tight.

These capscrews force the taper bushing into the
hub which in turn compresses the bushing onto the
shaft. This makes a positive clamping fit. The torque
must not exceed 24 ft. lbs. for Q bushings and for R
bushings.
WARNING: Do not attempt to pull bushings flange
flush with hub end. There should be
ance when tightened.

Removing Propeller Assembly From Shaft

Propeller is easily removed from shaft by inserting and
tightening two of the capscrews into the tapped holes
in the bushing flange. This forces the bushing loose
from the propeller and releases the compression so
that the entire assembly will slide from the shaft.

1. Remove all three capscrews from propeller and hub

2. Start capscrews into the threaded holes in the

3. Tighten each bolt part of a turn successively to

4. Pull the bushing off the shaft. If the assembly has

For propeller dimensions, see drawing R-9183.

B

DO NOT LUBRICATE

CAPSCREWS, BORE, OR

BUSHING BARREL.

C

D

A

1

∕8" to 1∕4" clear-

assembly.

bushing flange.

force the propeller off the bushing.

been in place some time, it may be necessary to
use a wheel puller to remove the bushing. Never
use a wheel puller on the propeller.

®

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