Twin City ES-404 User Manual

Type 'E' Adjustable Pitch Propeller

INSTALLATION, OPERATION & MAINTENANCE MANUAL

ES-404

June 2004

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 finger­tight. 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.

Table 1.

TORQUE (ft. lbs.)

FAN HUB

SIZE DIA.

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

BUSHING BLADE BUSHING
BOLT BOLT

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 propeller assembly to the shaft. When properly
assembled, the bushing 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 running 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 and held in place by compression. This gives
added driving strength.

Figure 3.

Figure 1.

Alternate Method

1. Loosen the blade retaining bolts until they are finger­tight. 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 indicating marks at 5° increments are
in between the two longer marks. See Figure 2 to the
right.

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.

©2004 Twin City Fan Companies, Ltd.

Put the bushing loosely into the propeller. Do not press
or drive. Start the cap screws by hand, turning them
just enough to engage the threads in the tapped holes
on the propeller. Do not use a wrench at this time. The
bushing should be loose enough in the propeller to
move slightly. Be sure the shaft and keyway are clean
and smooth. Check the key size with both the shaft and
bushing keyways. Slide the propeller and bushing
assembly onto the shaft, making allowance for endplay
in the shaft to prevent rubbing. Do not force the propel­ler and bushing onto the shaft. If it does not go on
easily, check the shaft, bushing, and key sizes.

Figure 2.

Tighten the caps screws progressively with a wrench.
Do this evenly as in mounting an automobile wheel.
Take a part turn on each cap screw successively until
all are tightened to the torque shown in Table 1.

These cap screws force the tapered bushing into the
hub, which in turn compresses the bushing on to the
shaft.

WARNING: Do not attempt to pull the bushing flange
flush with the hub end. There should be 1/8" to 1/4"
clearance when tightened.

Removing the Propeller Assembly
from the Shaft

The propeller is easily removed from the shaft by insert­ing and tightening two of the cap screws 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 off the
shaft.

1. Remove all the cap screws from the propeller and
hub assembly.

2. Start the cap screws into the threaded holes in the
bushing flange.

3. Tighten each bolt part of a turn successively to force
the propeller off the bushing.

4. Pull the bushing off the shaft. If the assembly has
been in place for 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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