Vintage Windmill and Wind Generator Forum

Is the spread on a 3 post tower, at the ground level, the same on a 3 post tower, as on a 4 post?

I know the spread is different on various heights. But let's say, is a 40' 3 post tower the same spread as a 40' 4 post tower.

Ken they're wider on the three leg tower.the base is 10ft3/4 inches

I forgot to mention that is for a 6 or 8 foot mill

I have a 20' 3 post tower and will compare with the width at 20' on the other 4 post towers I have. More to come....

My customer in Maine has a 40' 3 post tower unassembled with part of the lower part damaged and needs to add 7 ft to it. I'm trying to make an extension for it. He is getting a new 8 ft 702 mill from me and Dakota windmills makes a mast pipe and special furl lever for the 3 post. Using one of my modified pitless adapters, the windmill will pump underground from his well to a pressure tank in his house.

Very nice Ken. Maine that's my neighbor state

Ken,
Measuring the distance between 2 uprights, I'm finding that the distance is greater on the 3 legged tower. My Woodmanse 3 leg uprights are 10"-12” further apart at 20' than the three 4 post towers I was able to measure.

Ground footprint is roughly the same, however. The distance between the uprights that are diagonal to each other on the 4 post at 20' is roughly the same as the diameter of the circumcircle drawn around the 3 post at 20'.

Hope this helps.

Thanks for all the information. This will help me in designing the tower extension.

Keep in mind the distances between legs on 3 legged and 4 legged towers are from different points. The leg spread (from leg to leg) of a 3 legged tower is always going to be greater than that form a 4 legged tower even if the base is the same.