Aerovent IM-176 - Manual

Blade Angle Adjustment
Blades are set to the specified blade angle at the factory. If
adjustment in the field is required, use one of the following
two methods:
Preferred Method (more accurate)
1. Lay the hub on a horizontal surface with the concave (air
leaving) surfaces of the blades facing upwards.
2. Loosen the blade retaining bolts until they are finger-tight.
At this point, the blades should rotate in their sockets when
grasped firmly and twisted, but not turn on their own.
3. Place an angle meter across the two blade angle position
marks on a blade. See Figure 1.
4. Twist the blade to the desired blade angle.
5. Repeat steps 3 and 4 for the remaining blades.
6. Re-tighten the blade retaining bolts to the torque shown in
Table 1. Work in a star pattern, working your way up to the
desired torque in steps. Tightening one bolt to the full
torque before moving on to the next can crack the hub.
Alternate Method
1. Loosen the blade retaining bolts until they are finger-tight.
At this point, the blades should rotate in their sockets when
grasped firmly and twisted, but not turn on their own.
2. Angle setting marks on the blade line up with an indicating
arrow on the hub. There are two long marks on the blade,
one for 12° blade angle and another for 32°. Shorter indi-
Type ‘E’ Adjustable Pitch Propeller
General Installation, Operation and Maintenance Instructions For Aerovent Products
Table 1.
TORQUE (ft. lbs.)
FAN HUB
BUSHING BLADE BUSHING
SIZE DIA.
BOLT BOLT
14 - 24 6" H 17 7.5
30 - 36 9" P 30 13
42 - 48 12" P 75 13
42 - 48 12" Q 75 24
©2004 Aerovent
Figure 1.
cating marks at 5° increments are in between the two longer
marks. See Figure 2 below.
3. Twist each blade to the desired blade angle.
4. Re-tighten the blade retaining bolts to the torque shown in
Table 1. Work in a star pattern, working your way up to the
desired torque in steps. Tightening one bolt to the full
torque before moving on to the next can crack the hub.
Mounting the Propeller Assembly
on the Shaft
Type ‘E’ propellers are furnished with hubs that have a tapered
bore. A split-tapered bushing is used for mounting the propel-
ler assembly to the shaft. When properly assembled, the bush-
ing grips the hub and the shaft with a positive clamping action.
See Figure 3 below.
A. The bushing barrel and the bore of the propeller hub are
tapered. This assures concentric mounting and a true run-
ning propeller.
B. The cap screws, when tightened, lock the bushing in the
propeller.
C. The bushing is split so that when the locking cap screws
force the bushing into the tapered bore, the bushing grips
the shaft with a positive clamping fit. This will withstand
vibration and punishing loads without loosening.
D. The propeller and bushing assembly is keyed to the shaft
Figure 3.
Figure 2.
IM-176
June 2004