Vintage Windmill and Wind Generator Forum

windybob wrote: ↑Thu Feb 28, 2019 5:51 pm Probably 90% of the windmills we work on in the field are not centered over the well. However, most have been there for many years. Rare to find one that's really good.

I would think that the top of the windmill tower being directly over the well would be more important than the well being in the center of the base of the tower.

Bryon

I am working with a 3 legged tower. each leg is 120 degrees, math gets a little more complicated .
what angle should the anchor legs be set into concrete ?

All 3 leg footprints are not the same footprint/angle.

Most 3 legs have a broader side footprint than the side of a 4 leg.

Applicable to Aermotor:

4 leg - 27' height, side width at base 66 3/4"

3 leg - 27' ehight, side width base 81 3/4"

Use right angle calculator on line, your knowns are the length of 2 sides of your triangle.
27' or 324" is your hypotenuse.

Half the width of a tower side is your length of your other known side of a right angle triangle-
3 leg is 40 7/8"
4 leg is 33 3/8"

You now have the above values for solving:
3 leg 82.8 degrees
4 leg 84.09 degrees

Link to right angle calculator
https://www.mathportal.org/calculators/ ... ulator.php

Ron Stauffer
Montrose CO

The page out of T Lindsay's 702 book to verify the 4 leg angle


Your best way is to measure your tower and use the online calculator.

But the best and easiest is to measure your sides, dig your holes, hang the tower from a hoist, attach anchors and pour fast set concrete

Ron

I'm not even touching this one. The last time I had a hypotenuse I went to the doctor.

windybob wrote: ↑Fri Mar 27, 2020 6:50 pm I'm not even touching this one. The last time I had a hypotenuse I went to the doctor.

THANK YOU for the plethora of responses !
I am glad there are soo many out there that are significantly more intelleigent than I , and willing to share that knowledge !
great company of windmill people.
Mike B

I’m planning on doing the billcobb tower installation method. I’m wandering what the average size hole is and how much concrete per hole. 8ft Dempster 12a on a 28ft 4 leg tower. Is 1/2 yard per hole in sandy soil enough? Thanks

Ron Stauffer wrote: ↑Wed Feb 27, 2019 9:26 pm I have done a few anchor sets only but usually set mill and tower and attach anchors.

We do a variation of Todd's method. Instead of cutting exact length 2X4 we have four 10' 2x4s that have the length of 27 & 33 towers sides marked on the angle. Each 10' 2x4 is allowed to run wild. An added benefit is that the run wild end is far enough away from the anchor hole to allow support from either blocking or form stake. I have never had the bottoms of all four holes level and usually 3 anchors are dangling. We put a 45 brace on each corner to keep a square instead of a trapezoid.

Ron Stauffer
Montrose CO

Thank You, Ron. I couldn't remember where the information came from until I reread this post. In my case, one end of the form lumber was cut to the same angle as the tower. I numbered the legs and turned them over and used spray paint at the top of the form. I then cut each leg 3" shorter so it would be hanging in the air and welded on the cross bar. I also hoovered out the bottom of the hole so all the loose dirt was gone.