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     It is important to use a tower high enough for good wind exposure from every direction. The mill will pump more often and will be safer in storms. The wheel should be at least 15 feet above surrounding wind obstructions, such as trees and buildings, within a radius of 400 feet.
     Please read thoroughly thru these instructions before attempting to install your Aermotor windmill. It will not only save you time, but it will also enable you to get maximum performance from your windmill.


     It is recommended that there be at least two men, working together on the installation to make the job faster, safer and easier. Be sure there are no electrical lines that could come in contact with the mill or tower during installation or service.


Mill Size
in inches
per min
at wind
Long Short
X 6' 5 3-3/4 18 210 32 15-18 125 100
A 8' 7-1/8 5-1/2 18 355 32 15-18 105 175
B 10' 9-1/4 7-1/4 18 655 26 15-18 85 330
D 12' 11-1/4 8-1/4 18 1130 21 18-20 73 540
E 14' 13-1/2 9-3/4 18 1870 18 18-20 62 805
F 16' 14-7/8 11-3/8 18 2585 16 18-20 53 1180

     The Aermotor windmill can be completely assembled on the ground and hoisted onto the tower with a crane, boom truck or other similar equipment. It can also be assembled on the tower. The method selected will depend on the installers experience, his equipment and the size of the windmill. A gin pole, block and tackle for hoisting the mill into position is satisfactory for smaller size mills. Larger sizes will need a crane or boom truck to accomplish the installation.
     The Aermotor windmill can be installed on any brand steel windmill tower, or you can use a wood tower,  with the use of a stub tower that bolts to the top of the old tower to match the notching around the post that you set the mill on. No stub tower is needed if you are replacing an Aermotor. Be sure your tower is strong enough to support the weight of your new mill.
    Assembly of the stub tower begins by installing the post into the stub and bolting it in place. Measure the stub 4" above the bottom if it is for a steel tower, or 6" above if it is for a wood tower, and saw off the old tower at the point where it is the same width.
     Slip the stub over the top of the old tower, plumb it very carefully so the mill mast pipe will be perfectly aligned vertically, and mark and drill holes for the bolts. Use 4 bolts in each corner.


Mill Size 6' & 8' 10' 12' 14' 16'
Stub Height          
3' 9-1/2" 10"      
4' 11-1/2"   13-1/4" 13-1/4"  
7' 19" 19" 20-1/4" 20-1/4" 21-5/8"
14' 35"        
  Be sure your platform is strong and   secure. Replacements are available.   Wood platform for on a windmill tower.


     Slide a sail rib (#101) over the small end of the sail toward the large end until it fits into the rectangular hole in the sail (#100), as indicated in the drawing. Repeat this process for all 18 sails.
     Lay three sails in position as shown in drawing. Connect the inner band (#35) to the sail tab with bolts and lock nuts. Do not tighten the lock nuts yet. Note the distance that should extend in dimension 2 table.
     Slide the outer band (#34) through the rectangular hole in the sails until bolt holes of outer band match the bolt holes in the sail ribs. Dimension 1 indicates the correct measurement when #34 is installed correctly.
     Tighten all lock nuts in wheel section and repeat this procedure until the other 5 sections are completed.
#799 Complete Wheel Check list
Sails #100 18
Sail Ribs #101 18
Outer Bands #34 6
Inner Bands #35 6
Wheel Arms w/nuts #736 12
Bolts for sails 56
Lock nuts for sails 56
Furl Wire 25'
MILLS 6' 8' 10' 12' 14' 16'
Dimension 1 7/8" 1-3/8" 2-3/8" 1-7/8" 3-1/8" 3"
Dimension 2 1-7/8" 2-5/8" 3-1/2" 3-3/4" 4-3/8" 5-1/8"

Note that dimension 1 relates to distance between sail rib bolt hole and the first of two holes on the end of the #34 outer wheel  band. Dimension 2 refers to the distance from the sail tie to the end hole on the #35 inner wheel band. These are taken with sails laying down and measured on left.

Section of windmill wheel assembled ready to install. Windmill tail and vane for Aermotor windmill
Assembly of the tail bone starts with mounting it on the vane, with the hardware below. The point is bolted through the vane and the u-bolts align and secure it.
Vane hardware for attaching the vane to a windmill tail.
     Assemble the mast pipe with base into top of tower by putting the mast pipe into the top of the tower and securing the corner of the base with a short bolt, on the same corner as the furl handle is mounted at the base of the tower. Use the two longer bolts to secure the supporting angles on the furl lever to the side opposite the one which the furl handle is to be, so the furl wire will pull across the tower and clear the inner edge of the platform.
     Remove the #578 locknut and #579 lockwasher from the top of the mast pipe. Grease pack the friction washers #576 in the turntable, as well as greasing the mast pipe stem. Slide the upper furl ring down over the mast pipe and put it in position on top of the lower furl ring.
     Install the crated motor on the mast pipe using a gin pole, block and tackle or crane, depending on the size of the mill and equipment available. Once the motor is in place on the mast pipe, put the lockwasher and locknut onto the top of the mast pipe and tighten the nut.
     Remove the round pivot bolt #510 from the tail bone and place it into the top lug on the back of the main gear box case, through the bracket on the #659 buffer device, and through the bottom lug on the motor. Hook the head of a #528 furl arm into the cup on the #786 brake lever casting and slide the other end of the #786 up onto the pivot pin on the bottom side of the case at the shaft side of the motor and install the cotter pin to retain it. The other #528 goes into the cup on the end of the #585 tailbone casting. Then slide the #585 onto the bottom of the #510 pivot bolt. Place one end of the #527 connecting rod into the midpoint hole of the #786 and up through the hole in the #585 at the opposite end as the cup. These rods should all be straight and no need for bending is necessary.
     Install the tailbone and vane over the top of the stud end of the #510 pivot bolt, and the bottom end will align with the bottom of the pivot bolt, allowing you to secure it with a bolt through the #510 and the tailbone. Be sure that the lug on the bottom of the end of the #585 hooks over the bottom of the tailbone so it can furl the mill out of gear.
     Slide the #171 pull rod up through the center of the mast pipe unit and connect the head of it into the base of the #608 yoke, using the #610 pin to secure it. Screw the #580 vane spring hook into the motor case between the pivot and the buffer. When properly installed and tight, it will stand with the open side facing away from the tailbone. Hook the #28 vane spring onto one of the holes in the tailbone, and the other end on the #580 vane spring hook. The end of the #28 vane spring with the long hook goes into the tailbone hole, and the open side of the hook faces up. For maximum speed hook the spring into the farthest hole on the tailbone. When you wish for the mill to be furled out of the wind at a low speed, you connect to the first hole in the tailbone. There are holes in between that will allow you to select a speed that is desired.
     Attach the furl wire to the end of the furl lever and route it down through the platform and across the tower to the furl handle below, on the opposite side of the tower. When installed this way on a 4 post tower, the wire clears both the platform and the pump pole. Adjust the furl handle so the arms of the furl lever will bear onto the nuts of the bolts that hold the supporting angles, when pulled completely down.
     Furl the mill out of the wind and be sure the furl handle is secure so there is no chance of the wheel turning into the wind, while you assemble the wheel.
     Go to windmill instructions, part 2 to proceed with the assembly of the wheel.


Windmill Instructions Part 2

Windmill Care


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