It didn't last 1 night

[SmoggyTurnip]

I woke up last Sunday morning and looked outside and thought "This is the perfect day to put my gennie in the air".  It was sunny and no wind.  I had a friend help mount it and raised the tower by about 1pm.  It was very exciting to finally see it in the air.  By now there was a gentle breeze and it was turning at about 4 RPM. I had it connected to electric hot water heating elements in a 5 gallon bucket of water at the bottom the tower.  I had a switch on it and I disconnected the load and the blades spun up nicely with out any load.  As the day went on the wind speed was gradually increasing and by 6:00 pm the wind was close to 20 mph - it was turning about 175 RPM and making 3KW.  My father and a friend were standing at the bottom of the tower and we were all so impressed by the fact that it could not be heard at all.  

The wind speed continued to increase and it began to furl - I called the weather station and they were reporting a wind speed of 20mph - This is exactly where I wanted it to furl.

Winds continued to increase and at 7:30 the water was boiling.  At 8:30 the bucket was half evaporated.  I was not expecting winds like this at all.

The winds kept increasing and I would check things out every hour.  It was running smooth and quiter than I thought it would be.  It was dark out when the wind got to 30mph.  I could not see the top of the tower so all I had to go by was the sound.  It was just making a nice swishing noise.

At 2 AM the weather station was reporting 40 mph winds with gusts to 50 mph.  It was pitch dark so I still not see anything but is sounded good.

At 3 AM the wind was 50 mph with gusts to 60mph!  I went to check on things and It still sound OK until I turned to go back to the house.  There was a big "BANG!".  "What the *$&^# was that??"  It scared the hell out of me and I ran!

Then I stoped and listened - I wish I could see the thing - but it sounded OK now.

Then BANG again .

This was scarry as hell.  It kept happening at random intervals between 20 seconds to about 2 minutes in between.  The noise was terrible and I was helpless to do anything about it.  "I wish this dam wind would stop!"  But it wouldn't let up.

This noise kept up until about 5:30am when there was a sudden lull in the wind.  I ran to the base of the tower and shorted the turbine out.  It was still too dark to see anything at the top of the tower.

At 6:30 AM the wind was dying down and the I could finally get a look at the damage.

Here is what I saw:

It seems that the blades were striking the tail!  But why?  I thought I had enought clearance.  I had more clearance for the tail than I had for the tower (18") so How could it hit the tail and not the tower?

Also looking around I had a big shock when I saw 3 guy wires disconnected!  The turn buckles completely backed off!  One guy wire at 90ft and 2 at 60ft Yikes - I am lucky to have anything left at all.

I took the thing down the next day and found that the bearing was gone as well.  I could just barely turn the generator by hand but the stator and rotors saw no damage.

I could tell by the scratches on the pipe that the tail stop rode up over the pipe that was suposed to stop it and I think that is why the blades struck the tail.

One blade was broke - one was cracked and the other had no damage that I could see.

I built 3 new blades since then and I hope to have it in the air again this week.

Forcast is for 40mph winds tomorrow!

[AbyssUnderground]

Sorry to hear about the damage. It certainly looks a fine machine.

[makenzie71]

The "stop" for the tail boom needs to be cradled.  Take a three or four inch diameter piece of pipe about three inches long and cut it half down the side to make two troughs.  Weld one to your stop.

[SparWeb]

Very sorry to hear about your troubles.  None of our creations will last forever, but so much trouble so soon must be very disappointing.  Looks like you're not daunted yet.  Any idea what happened to the detached guys?  There is a means of locking turnbuckles with wire wrapped around each end that you could try.  (It's an aviation thing - I can send you a diagram if you want).

[Flux]

Once you lost balance then the vibration most likely loosened the guys. Locking turnbuckles and shackle pins is always wise.

No doubt you don't need a lot of advice about tail stops, you have no doubt realised that something more positive is needed. A bar welded on the tail to contact the alternator mount at full furl is usually convenient.

You were a little unlucky to have so much wind on the first trial, especially at night.

Otherwise you seem to have had good results, no doubt it will be fine when teething troubles are sorted.

Was the brake switch not able to stop the thing after the bang or were you just too frightened to get near to try it.

flux

[Ungrounded Lightning Rod]

A bar welded on the tail to contact the alternator mount at full furl is usually convenient.

That's how I'd prefer to do it, too.  (Perhaps with a bumper of an energy-absorbing rubber, say from an automitive suspension or auto door, to cushion impact in very strong gusts and thus avoid bending the tail.)

IMHO making a furling stop solely from a cutaway on the hinge is asking for trouble.  Even if it's shaped so the tail can't ride up on the pin and go over it, you've got an ENORMOUS lever arm working against something that close to the axis when the tail comes swinging against the stop.  Even if it works initially I'd expect it to deform with time, as the stop is struck repeatedly, and eventually let the tail go forward enough that it will strike the blades on some particularly strong gust.

Of course the tail should USUALLY be moving pretty slowly when it fetches against the stop, so perhaps I'm being overcautious.

[SmoggyTurnip]

"Was the brake switch not able to stop the thing after the bang or were you just too frightened to get near to try it."

I was way too frightened to go near it and I also thought shorting it out might burn it out and then I would have zero load and I thought that would be worse.

I do have a bar welded to the tail boom that comes in contact with the alternator frame.  I think what happened is that the tail boom hinge moved up.  It is just a pipe over pipe and there is nothing from stopping it from moving up.  Is this what is usually done or is there a standard way to stop that from moving up?

[SmoggyTurnip]

Yes I know about the wire locking thing.  It was kind ov ironic because a friend of mine droped by just after I got the thing up and he asked me if it was possible for the turnbuckles to turn loose on their own and I said "Yes I think they will over time" and I explained that I was going to put a wire through them to stop that from happening.  I didn't think that "Over time" would be  one night.

And yes I am not daunted.  But I do have a new respect for the wind and the dangers these machines can create.  I can't stop now - after all the thing generated at least 3 dollars worth of electricity - time for a new set of blades.

.

[SmoggyTurnip]

Also I was really kind of surprised that there was not more damage to the blades.  They must have struck the tail several hundred times.  And I was also impressed with the strength of the tower because there was only 3 guy wires at the top when this was happening.  The wind was from the south and it was the east guy wire that came off at the top.

I have the wire in the ground from the tower to my house and the next time it goes up I will be sure to have an adjustable load that I can control without going near the tower.

The reason I had the load at the base of the tower was that I can't see the machine from my house and I wanted to be able to watch the both at the same time.

.

[alibro]

How much grief did you get from her-indoors?

My missus used to give off something awful every time I had to bring my gennie down. Unfortunately being a total novice I hadn't built it that well and I had to bring it down regulary.

I sounds like yours will be better when you get it sorted and should give you a lot of pleasure.

Keep up the good work

AliBro

[ghurd]

Holly crap.  Sorry.  You put in such time and effort.

Unscrewed turnbuckles are something I never would have considered. Ever.

But she's working as designed!   'cept for that little glitch...

G-

[richhagen]

Wow, it could have been a lot worse.  If it hadn't been the first night, you might have been paying less attention to it and wound up with a tower lying in your yard with a smashed turbine at the end of it.  Blades, bearings , and a few other odds and ends and you will be back in the air.  You already have made the blades, and have been bitten by the fact that it works.  I would bet that the next raising will see it up in the air for a much longer time.  Rich

[jmk]

 What happened to the saying once you stand a wind turbine there will be no wind for days?I'm sorry to hear of the misfortune. That's one hell of a set up your doing. I hope it becomes an asset to you and your family.

 I think I will safety wire my turnbuckles and shackles. I have been thinking about it, but I have been retightening them after every windy day. It is starting to slow up and stay tight. I think I am just pulling my chain tight that I used to hook up to the dead man. The angle I set the chain is probably not straight with the guys.

Couldn't you hear the moaning noise that the alternator makes when putting out amps? I can hear mine for quite a long ways away. To me it sounds like growling ghost.  It's not that noticeable but once you hear it you will know. I am glad to hear you didn't loose the tower. I hope you get it fixed soon, and your house  water  is nice and warm. Hopefully it will become an asset to you and your family.

[Flux]

Lots of things happen with wind that ought not to. I don't think the tail hinge would lift with the weight of the tail normally, but when constrained by your stop, it may have caused a moment that did lift it. Your stop must be very close to the hinge to let the tail end move 18" without lifting the thing off the hinge.

I would be inclined to fix the hinge so that it can't lift.Most of my tails are different and they can't lift. It is very easy to modify something and introduce new factors. You were unlucky to have so much wind so soon before having a chance to see what is happening.

Flux

[DanB]

Rough...  sorry to see that.  I had that sort of thing happen a few times in the past and we always weld a positive stop to the tail boom now.  Also a good idea to wire the turnbuckles with baling wire or something so they can never come loose.  

Smoggy - can you recap the details of your whole machine, I look back through your stories but have a hard time finding all the stuff in one place.  Curious to be reminded about the magnet rotor diameter, the size and number of magnets, details of the coils/stator, and blade diameter.

[nothing to lose]

Glad it was not any worse and survived well.

 Sounds like you built a real power house genny there, just a couple bugs to work out.

Great job. And thanks for posting it, I probably would not have thought about turn buckles unscrewing either, though I sometimes like to double nut them. I do that myself so that a washer and nut help hold the force instead of just the threads.

Although I hate them for normal all the time use, Halogen rechargable flashlights are great to have around! Those big fat ones with about a 7amphr SLA battery inside, $15-$20.

 I think full charge they only last about 30 minutes when new, but times like that they are great to have around.

I built my own also, Cheap Halogen driving lights from a car, 2 for $15 new as a set often with everything but battery, or get some wire, switch and any 12V battery handy I can carry easy.

It's great to be able to see 500ft or better like that at times like those!

Also good when something in the woods is growling at me at 2am, I get the light when I go get the gun!

[ibeweagle]

Sorry to see the Damage we are using all thred and nuts and washers trough the tail pipe to hold it from comming off the tower when we lower it as it is a hindged tower on two 20" pipe old tv tower with guys think that will work for prventing the tail from riseing up cheers ibeweagle@hotmail.com

[Murlin]

Wow, what a stroke of bad luck....sorry to hear that.

Murlin

[bj]

    Smoggy--sorry to hear of failure.  Not too catastrofic, but a

setback.  You seem to be able to bare that tho.

    Vibration is a problem.  Especially when it is in the same axis

as whatever you want to keep tight.

    You can do the safety wire thing, with some success, but sympathetic

vibrations will loosen almost anything , with time. My estimation is

based on years of balancing.  (Engines)

    So---What I have done on a small set of blades is--Weigh the small

end, weigh the big end, and make all equall.

    So far they have done well.  Two years, and not a fault.  But only

500 watts.  Not a bearing failure or anything.  Not a big machine, but

very dependable.

   In future--can I help?

   If  can, please call.

   bj