mill "tower" didn't last long

[elt]

The support pole for my mill "failed" late last fall; that bummed me out at bit... The good news is that the mill was working long enough that the boss thinks we saved on electricity (I'm not sure it wasn't mostly conservation) and she has okayed a section of larger pipe to get it back up in the air.

A real tower has been a thorn in my side because there's no place for a guyed tower except in the front yard and that's been vetoed by the boss. Until I can get my self-supporting tower up, I put the mill up a short piece of 2" pipe bolted to the millshed.

I don't recall anyone writing that 2" pipe was good enough to support a 10' mill but I do recall someone writing that they wouldn't even use it for the last few feet... I can say now that using 2" pipe is surely a bad idea.

First real storm we got put a little bend in the pipe:

That didn't seem so bad but it wasn't furling,the angle of the tail assembly was all wrong on top of the bent pipe.

About a week went by without me getting around to it and another storm came along. I woke up in the morning to see the blades rubbing against the top of the millshed. Here's a pic after I strapped the blades to the pipe to keep the mill from turning:

As crashes go, that one wasn't too bad. The worst damage (after the pole) was a little ding in one blade where it hit the roof of the millshed at speed. I'm sort of glad it did find a way to stop itself as it was making well over 50 amps during the storm. I'd wanted to furl around 35 amps so I fretted about the controls (and the alternator) but appears I had enough headroom; everything seems to have survived at least as far as I can test things on the ground.

Insane energy prices have have lit a little fire under me and the boss reiterates her desire to see the mill working again...

I see more people looking at larger mills for heating. I'm personally wondering about a mill running a heat pump; seems like a way to leverage your wind energy by a factor of three or four but am just starting to look into so (as with most topics in RE) I don't know diddly yet...

Cheers,

- Ed.

he measured the pipe and it was only 1.5 inch (not 2 inch) as mentioned at the end of this thread

[jonas302]

I don't want to laugh at you misfortune but that sure is a neat pic!

It is amazing how much force your windmill made on the pipe I hope some of the people with tower questions see your story

[Dave B]

 Thank you for sharing with us your mis-fortune so we all can learn and be a bit safer because of it besides, thank fully it sounds as if no one was hurt.

 I have been through it and others here besides and I will continue to say that ... it is not a matter of "if" but rather "when" all of us will experience high winds with our machines flying.

 The numbers don't lie. If you are even just a bit anxious when nice winds of 20-25 MPH blow through ask yourself this ... If it ever gusts even to just 40 MPH winds, can my turbine as well as my tower survive 8 times the stresses I am seeing at 20 MPH ? You will know soon enough.

 Thank you again for sharing and we look forward to seeing it back up flying again soon. Stay safe everyone,  Dave B.    

[phil b]

Sorry about your misfortune. All of us learn from mistakes.

If you have no room for a guyed tower, then build a self supporting one. Use 3 or 4 upright posts and weld supports between them.

Look at Rohn 10 meter (33 ft) towers as an example. The tubes are about 1" dia. with 1/4" rod welded between them for support.

I googled Rohn and found new 10 ft sections for $230 each delivered. They can also be purchased for less than half that used if you prefer.

With a tower no taller than yours, you should be able to sit in the middle of it while the ends are supported by saw horses without it breaking.

have fun!

Phil

[phil b]

Sorry, I skipped reading all the story because I didn't wait for dialup to load everything. My first tower doubled over instead of bending. I was too excited about getting the genny into the air. After that, I started paying more attention.

[elt]

I really didn't expect the pipe to bend when I put it up. I did reinforce the shed internally thinking that it might suffer but I really thought the pipe would be okay... Well, at least the shed survived!  - Ed.

[richhagen]

Nice photos.  Sorry about the misfortune, but as you noted, it could have been a lot worse.  Obviously you will be building a larger diameter tower or lattice design, and I look forward to reading about that project.  Rich

[bigkahoonaa]

Bummer.  I guess two inch pipe isn't a very good idea.  From your pics, even guy wires wouldn't help, but I like your idea of running a heat pump.  I have an open loop ground source heat pump.   It would be nice to drive it from a genny.

Big

[elt]

That was my thought, that the part sticking up over the roof was equivalent to the part that would be above the top guys in a guyed tower.

I don't think that the wind overcame the pipe all at once. I suspect that wind gusts over the previous few months flexed and eventually fatigued the steel to the point where the sustained high winds were enough to bend the pipe. If so, another demonstration of why its better to have the mill way up there away from the turbulence...

- Ed.

[wooferhound]

With your mast mounted to the shed like that,

did it vibrate or buzz the building ?

[elt]

To me, it hummed quite loudly. The "whisssh" that the blades made prior to cut-in didn't resonate inside the shed but I never needed an amp meter to know when the mill was starting to make battery volts... my original idea was to support the "real" tower on the side of the house but the noise has me thinking "someplace else."

Can't say that I ever felt that the shed moving or shaking; it just seemed that the wall made a very nice sounding board.

 -Ed.

[bj]

     ELT--As everyone is, sorry about misfortune, but glad it wasn't

worse.

     Had the same kind of thing happen a little more than a year ago,

with a guyed tower.  The comments about increasees in forces with

increases in wind speeds are worth listening to.  In my case the

constant pushing, shaking, and general vibration pulled one of the

guy cables through the clamps.  As with you, damage was only one

wrecked tower section.

     We all learn best from mistakes.

     Better luck in the future.

     bj

[elt]

Hi Rich,

I've had this DMX-32 for a while...




My plan had been to use the bottom three sections and then brace it at about 14 feet up against peak of the garage attached to the house. With a pipe at the top, that would get the mill up to about 30 feet. (I had a brief exchange with mitcamp who has put mills on DMX towers and he seemed to think that that would work well enough.)

The racket the mill made against the shed, though, has me thinking seconds thoughts. Now I'm not exactly sure where to put it but I'll proceed to make a base for the bottom and something to hold a pipe for the top and hopefully I'll get the location figured out along the way.

- Ed.

[richhagen]

DanF had a tower setup mounted on the side of his house, I think I recall he or DanB mentioning that there was a bit of noise from it and that the setup was not ideal.  If DanF reads this, he can chime in on his experiences with that setup.  Here is the top of his from when I was out there in 2005:





He had the Art Randolph fiberglass blades on it then.  

[elt]

Please accept my apology.

I want to correct some misinformation that I posted:

I measured the diameter of that pole; it was only 1 1/2" pipe, not 2" pipe as I originally wrote. I can't say whether 2" pipe is strong enough for the last 6 feet or not. ( But 1 1/2" pipe surely isn't!)

I'm sorry that I misidentified the pipe diameter and hope that that didn't cause anyone any trouble or grief.

- Ed.