Author Topic: 2nd prop failure on this unit....  (Read 3537 times)

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TomW

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2nd prop failure on this unit....
« on: October 29, 2008, 04:32:56 PM »
I apologize, my main computer turned into a plsstic doorstop last week and I haven't had time to get this backup computer set up to resize photos so I will just link to the largish orignals for those who want a look.


It was still pushing 200+ watts looking like this before I shut it down


http://www.otherpower.com/images/scimages/4/2ndbustedprop_1.jpg


Looks like it smacked the tail [again].


http://www.otherpower.com/images/scimages/4/2ndtime_tail_ding.jpg


Had this up a couple three weeks [this time] on my "test tower"at 30 feet. Fierce winds a couple days and when I went up to check on things it was yawing pretty early and seemed to be running smoothly pushing a steady 10 to 20 amps. So I let it fly.


This also happened awhile back on this machine but I made some mods [boom stop] that should have prevented the tail getting even close to the blads.


I am in a pinch for time so thats all I can post just now.


Tom

« Last Edit: October 29, 2008, 04:32:56 PM by (unknown) »

DanG

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Re: 2nd prop failure on this unit....
« Reply #1 on: October 29, 2008, 10:55:25 AM »






« Last Edit: October 29, 2008, 10:55:25 AM by DanG »

Flux

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Re: 2nd prop failure on this unit....
« Reply #2 on: October 29, 2008, 11:39:11 AM »
Bad luck Tom. Not sure how the stops were arranged but some of the suggestions I have seen will actually lift the tail on the hinge rather than prevent contact with the prop.


Flux

« Last Edit: October 29, 2008, 11:39:11 AM by Flux »

SparWeb

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Re: 2nd prop failure on this unit....
« Reply #3 on: October 29, 2008, 12:14:56 PM »
Aw man that sucks.  Are you sure it isn't the other mill taking shots at it?
« Last Edit: October 29, 2008, 12:14:56 PM by SparWeb »
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
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TomW

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Re: 2nd prop failure on this unit....
« Reply #4 on: October 29, 2008, 01:46:20 PM »
flux;


Here is a closeup of the yaw setup. Solid metal stop with a tire tread bumper as well as a thru bolt to keep the yaw bearing from coming off.


Again a large photo so just a link.


http://www.otherpower.com/images/scimages/4/2ndpropfail_yaw.jpg


Only found one piece of prop about 75 feet downwind so far.


Thanks for the response.


Tom

« Last Edit: October 29, 2008, 01:46:20 PM by TomW »

hiker

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Re: 2nd prop failure on this unit....
« Reply #5 on: October 29, 2008, 03:29:40 PM »
hows the setup differ from the mill in the back??

it seems intack..
« Last Edit: October 29, 2008, 03:29:40 PM by hiker »
WILD in ALASKA

vawtman

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Re: 2nd prop failure on this unit....
« Reply #6 on: October 29, 2008, 04:01:22 PM »
Hi Tom

 Looks like the Zubbly is still flying.Thats cool.


 I always wondered what effect heavy, wet, wind driven snow has on the tails of these creatures?Did you get that by you from the last storm?


 Maybe it's time to build a vawt before someone gets hurt :)

« Last Edit: October 29, 2008, 04:01:22 PM by vawtman »

TomW

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The other turbine..
« Reply #7 on: October 29, 2008, 05:16:46 PM »
hiker;


The other one is a Zubbly built conversion. No furling 6.5 foot diameter. Its built like a tank going on 3 years up with no maintenance. Zubbly wanted me to "test it to destruction" with no maintenance so thats what I am dong. Sadly, it has outlasted him. It has been hammered by 70 mph gusts [airport station 5 miles away gusts] and a sustained wind event of 45 MPH for most of one day. It just keeps on keeping on.


Tom

« Last Edit: October 29, 2008, 05:16:46 PM by TomW »

jmk

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Re: 2nd prop failure on this unit....
« Reply #8 on: October 29, 2008, 05:53:52 PM »
 Bummer Tom,

 I hope you get it fixed soon. They look like nice machines.
« Last Edit: October 29, 2008, 05:53:52 PM by jmk »

oztules

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Re: 2nd prop failure on this unit....
« Reply #9 on: October 30, 2008, 05:21:08 AM »
Sad to see this Tomw.


I am currently rebuilding the furling "bits" on my chainsaw mill, and after seeing the tail that could not possibly hit the blades... hitting the blades, I shall re-evaluate what I have done....


I have extended the offset tube out to 8" from 6".... the tail will now be a bit longer too.... all the easier to hit the blades now I look at yours and think about it.


Just doesn't matter which bit you change, it effects some other bit... that effects some other bit and so on......


...........oztules

« Last Edit: October 30, 2008, 05:21:08 AM by oztules »
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fungus

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Re: 2nd prop failure on this unit....
« Reply #10 on: October 30, 2008, 05:59:38 AM »
oops... looks like you'll be able to hone your woodworking skills some more.


makes you wonder what caused this though, is there any chance of the tail going up on the slide tube that it sits on so that it can bypass the stop ? If the blades hit the tail but not the tower then that's a good indication the stop didn't work as planned, blade flex doesn't really factor in to it then.


hm... jacques posting as fungus because someone seems to have logged me out :)

« Last Edit: October 30, 2008, 05:59:38 AM by fungus »

fungus

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Re: 2nd prop failure on this unit....
« Reply #11 on: October 30, 2008, 07:01:33 AM »
I told ya to log me out but did you listen? .. :)

Was wondering why this post showed up as 'read' :P

@Tom: looks nasty .. but should be salvageable I guess ..
« Last Edit: October 30, 2008, 07:01:33 AM by fungus »

KEG

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Re: 2nd prop failure on this unit....
« Reply #12 on: October 31, 2008, 09:39:41 PM »
Now that realy sucks!

is any of the tail boom bent, or the hinge pivot or pivot angle plate.

once you can get it down to fold it up for a test I'm sure it will show it's ugly face :-(

this is how I made mine and it's still going strong.



« Last Edit: October 31, 2008, 09:39:41 PM by KEG »

TomW

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Postmortem Forensics reveal....
« Reply #13 on: November 02, 2008, 05:13:38 PM »
Well, guys. The failure was not in the yaw mechanism. It was an error in a much more complex assembly, the installer.


I neglected to secure the back rope for easing the 4 leg tower onto its bolts after I got it pulled up. The angle allowed the prop to hit that rope which was still in place. The rest is history, as they say.


Picture of the nicked rope and where the undamaged prop would hit it is here:


http://www.anotherpower.com/gallery/album123?page=2


Only ever found one tiny piece of the blades its shown in this gallery:


http://www.anotherpower.com/gallery/album123?page=1


Normally this rope is secured close to the tower and tight so its not in the way.  Big gouge in the back rope  tells that tale quite well. Pretty silly amateur mistake. I checked all bolts for tightness after the vibratory event and all were tight before I put on the 4415 8 foot prop and pulled it up.


So now its got an 8 foot prop on and should be OK til I get a 10 footer sorted out for the new tower.


That prop is documented over here:


http://www.anotherpower.com/gallery/4415-8-foot-prop-project


Maybe I shouldn't be fooling with this stuff but at least its 300 feet from the house.hanks for all the comments.


Tom

« Last Edit: November 02, 2008, 05:13:38 PM by TomW »

ghurd

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Re: Postmortem Forensics reveal....
« Reply #14 on: November 03, 2008, 12:17:32 AM »
I would sue the installer.  Twice.


I don't see the rope in the pics, and I am not clear about where it was connected to the tower.

Right at the top?


Pic 13 of 13.  That's like 13^2.  You should have seen it coming!

G-

« Last Edit: November 03, 2008, 12:17:32 AM by ghurd »
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SparWeb

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Re: Postmortem Forensics reveal....
« Reply #15 on: November 05, 2008, 01:55:49 PM »
Admitting to one's own mistakes.  I admire your candor.


How does the nicked tail figure into the tale?  Struck by a segment of blade as it flew by?  Damaged on the ground, even before it was raised, and only noticed now?


Good luck with the new prop.

« Last Edit: November 05, 2008, 01:55:49 PM by SparWeb »
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

TomW

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Re: Postmortem Forensics reveal....
« Reply #16 on: November 05, 2008, 04:31:46 PM »
Steven;


No clue about the tail but it didn't appear to be as "fresh" as I would expect from having happened in this incident. The damage is odd in that it is a divot into the corner that crunched the inner laminations  which would seem odd for a moving strike from the prop which you would expect to tear away material rather than "bounce" away?


As far as admitting mistakes, isn't that what any honest man would do?


My old school upbringing is showing I guess.


Thanks for the comment.


Tom

« Last Edit: November 05, 2008, 04:31:46 PM by TomW »

SparWeb

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Re: Postmortem Ballistics Theory
« Reply #17 on: November 06, 2008, 12:34:55 PM »
Then maybe my earlier ballistics theory still holds.

It was hunting season, after all.

Maybe the other turbine is jealous...?

« Last Edit: November 06, 2008, 12:34:55 PM by SparWeb »
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca