Bent upper mast pipe

[Hillman 2]

I have my A602 down off the tower now, It's in need of repair. In one of our harsh monsoon storms this summer, the wind was so strong that it bent the upper pipe on the mast. It was pretty much my fault, I'll admit, because the furl linkage had worn to the point that the furl was not tight and the whole adjustment was not up to snuff. And, I had taken the brake band off because it squealed so loud. When the furl handle was down, It would come to about a 3/4 furl. Therefore, the fan would turn quite fast in a good wind, and this time it was just a little too much stress on that pipe. This windmill is 97 years old now and survived about 70 of those years on the North Dakota prairie without a bent mast. How common of a problem is this?

[Windcatcher530 Dan]

Is the mast pipe paper thin because of wear,then I could see it.

[Hillman 2]

No, I see no indication of wear, although I'll have to inspect that thought further. I'll measure diameters at multiple places along the length of the tube.

[windybob]

It's fairly common here. Put the nut in it, put it in a vise, heat it orange, slip a cheater over it and bend it back. Oh, take off the turn table also. Don't force cool it. let it cool slowly.

[Windcatcher530 Dan]

Windy when they bend the mast pipe are they furled or unfurled

[windybob]

I don't know how it happens. I just usually pick up an old mill and when I take it apart I see it's bent.

[Hillman 2]

I checked it and it isn't worn thin or worn in any detrimental way. I believe that back in the early 1900's they just didn't have the materials we have today. And that isn't a criticism, all of these kinds of things progress as time goes on. Now there are materials that will withstand the forces encountered here. So, instead of bending it back and most likely having it bend again, I'm going to take the upper mast tube out and replace it with a high carbon alloy. That should solve the problem.

[Ron Stauffer]

When an Aermotor is completely furled, it is unbalanced and the unbalanced weight puts a lot of down pressure on the mast pipe. The wear on a mast pipe is at the top third and bottom third of where the motor case swivels. The center has the cavity for oiling. You can see how much a mast is worn by putting a straight edge on it.

They can break off besides bend. We used to straighten ones that werent worn but had one fail that was straightened. Putting a pump rod even in a non pumper will keep the mill from coming the whole way to the ground if a mast fails

Ron Stauffer
Montrose CO

[Windcatcher530 Dan]

Ron your right about the pump rod. I was hauling a 6ft aermoter on a 20ft tower home i had just bought.i didn't remove the mill from the tower cause it was getting dark and had to get home. When I got home the head was dangelling off the end of the trailer just held on by the pump rod.