Ohh, Darn...

[TomW]

A couple days ago I had to shut the Danbilt down due to an ugly wobble. After looking from the ground in overcast weather I could not see anything obvious wrong.

Until today.

Nice, bright sun and the mill is facing away from the house so I quickly noticed the dings on the back of blade ends on the darker blades:

Sorry the photos are a 30X zoom from a couple hundred yards away to get the right sun angle. But you get the idea.

[DanB]

Hi Tom - too bad.  I think that machine wouldn't mind a bit off the diameter anyhow so I'd cut a bit off.

I think the tail hit the blades - I don't recall if we welded a stop on the tail boom there or not.  Looking at the pictures though it looks more likely that the tail hit blades than it does that the blades hit the tower.

[TomW]

Dan;

I took some fairly high resolution photos of that side of the tail vane. You may be right. There is some scuffing on the tail vane. it seems there is not a stop other than the slot in the tube.

Here are the photos of the tail from the side that would hit. Kind of big photo for detail so just a link:

http://www.anotherpower.com/gallery/album50/100_0365?full=1

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http://www.anotherpower.com/gallery/album50/100_0368

I just realized that as the tail furls it also tips the lower edge in so that ding on that lower front edge of the horizontal part may be from a blade strike.

It seemed to be furling somewhere around 20 MPH or so and could hold a steady 15 amp output with bursts up to 30 or so while I watched. I will miss the power even after only flying a short while.

Just wanting to share the info so others can learn.

I think Dan has modified his designs a good bit since he gave me this unit in January of '04. It just took me this long to get it up[ ands flying.

Supposed to warm all the way up to 40F Saturday so hopefully I can go up and look close and come up with a plan.  Not too inclined towards outside work on those single digit windy days especially at 60 feet up.

Just keeping you posted.

On another note, I gotta say that my Zubbly conversion is as tough as a nail. It has flown head on with no furling in winds that were said to be well above 35+ MPH in this area since I moved it up there a couple months back. It goes scary fast and can pump an occasional sustained output of over 250 watts. Long ago we determined that this motor conversion was less than optimal due to coil size / location. My main point on these is they are just plain tough as Zubbly builds them.

Just had to temper the failure report with a success report.

Ok thats it for now but more when I get the info.

Cheers.

TomW

[Jerry]

Hi Tom.

Sorry to hear about your set back. At least it wasn't a total crash and will or should be easy to redo.

I've noticed the same thing about my motor conversions. I fly them with no furling head into the wind. My 2000 watt 24 volt Has been hammered with 2 years of winter storms and keeps flying. It has 7 ft Lakota blades.

                    JK TAS Jerry

[JW]

Im with Dan's suggestion on this one, just cut the blades a little shorter and be done with it for now.

 nice to see the guys with alot of experience like TomW, Danb, and Jerry commenting.

 Its the pratical applications, not theory that give this site its true backbone

JW

[TomW]

JW;

Well, with the wicked imbalance it exhibits, I think it may have misaligned the blade spacing or something else. Tomorrow I should be able to get up and look at it close. Dan thinks I need a stop welded on for the tail boom anyway so I will probably pull the head off and get it down where I can work on it. Just hoping the prop is not mangled beyond use. It will need to be cut down and rebalanced which is easier to do in the garage out of the wind than up where it seems breezy all the time. Thanks for your comments.

Time will tell.

Cheers.

TomW

[JW]

Hi Tom,

 If the blade spacing is misaligned, do you suspect one of the blades is loose. I cant even imagion the kind of havoc that would cause on a mill.

I hate it when TIME tells on me

Cheers

JW

[TomW]

Dan;

Well, I climbed up there today and looked up close and found good evidence of a blade / tail vane impact. That red blade is split from tip to root about 1/2 or 3/4 of an inch back from the leading edge. A clean split and still more or less all there  no hunks missing. There is no way it hit anything but the tail. I could just barely shove the tips in far enough to hit the tower parts and the bearing and yaw stuff is all the same as when I put it up. No indications of any hit on the tower, either.

Was too windy to disassemble things but I will pull off the prop and see what I can come up with as a fix. Not sure if gluing is an option for it but all the prop forces seem like they would be along the split and wouldn't stress it much. I will also be cutting it down if I reuse it or put on a smaller prop if it needs to be replaced.

I see in your Sunday post this week that that newer mill has the stop on the tail boom. Is that a good option? If so it would be much easier to remove the tail assembly than take the head down to weld it. I should of realized that the newer units use a stop and done that over the 2 years it gathered dust in my shop area.

Just an update.

Cheers.

TomW