Author Topic: tail hinge re-work  (Read 8336 times)

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kitestrings

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tail hinge re-work
« on: September 02, 2016, 04:28:18 PM »
So I'm finally back to on this project again - where'd the summer go?  Some people work there tails off.  I've just been working to remove mine.



Of the things I missed on with this design, I'd say I surely wasn't paying close attention to the hinge angle.  The original design angle was supposed to be ~20 deg IIRC, and when it was all done and I measure it we were very close to 30 degrees.  Some damn fool hadn't calculated things quite right....and then we wondered why it furled so late.  Adding to the problem the weight of the tail and vane was a bit under-estimated.  My project is here if anyone is interested:
http://www.fieldlines.com/index.php/topic,148058.0.html

Using the actual weights and COG I'm now coming up with a design angle of only 16 degrees (off vertical); it is 45 degrees rotated in plan-view.


I'm also replacing what I call the BAB (big asterisk bolt) with a new hinge pin.  My wife sometimes questions things in the shop labeled BAB, or NFG ???.  Not cut to length in the photo, but it is a piece of C440 polish stainless which will bear on graphite/bronze radial bearings top and bottom.  The BAB was rusting quite a bit already and the extended portion of the threads was "chewing" at the lower bearing.  My plan is to re-bend the top plate, have a weather-covered roll pin at the top, and just float the bottom of the pin in the lower hole/socket.  I also picked up a 2-piece stainless alignment washer for the lower, thrust bearing.  I like that it is convex which should keep water away while insure alignment.

More to come, but this is where I am, and as always welcome comments.  Kindly, ~ks



ontfarmer

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Re: tail hinge re-work
« Reply #1 on: September 03, 2016, 05:39:24 PM »
Great that you are back at it. You have done very impressive work on your project.
I changed to less angle on the tail of mine several years ago. The furling worked much  better more gradual. I turned out plastic bushings one with a collar on it for thrust that has worked good.
Your bearings will certainly last. The tail bracket looks there is some weight there? Great idea
for the stop and some cushion to it.

Boondocker

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Re: tail hinge re-work
« Reply #2 on: September 05, 2016, 08:22:25 AM »
Hello Kitstrings,

At what wind speed was the furling happening before the modification?   Full frontal exposure on 15' diameter machine, at higher wind speed, had to be testing the entire system.

20 Degrees may be still be a little "strong" .  H. Piggott published 15 degrees in the Windpower Workshop book.  C. Olsen recommended 18 degrees on his high voltage MPPT wind turbine design.

Also, what's the hub offset?

Thanks for sharing,

Boondocker

kitestrings

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Re: tail hinge re-work
« Reply #3 on: September 06, 2016, 09:05:06 PM »
Quote
The tail bracket looks there is some weight there?

Yes.  The tail boom, inner boom and brace are about 30# (lbs).

Our original tail vane was SS, and it weighed about 20# not counting the strut, so we pretty quickly changed this to AL and that dropped about 7#.  I'd say at this point we were furling at about 25 mph.

I've been using Hugh's updated method (below), but somehow I just botched the angle.  The original design angle was supposed to be 19 degrees and we ended up closer to 29 degs.   Oops.  I'm aiming for a bit lower furling point and about 16 degrees now.

from Hugh's Windmill Wind Power Workshop                              
                              
THRUST:                              
d (m)      v (mps)         kg   #   offset (in)   offest (m)   mkg   ft#
4.572   ^2   9   ^2   33   51.31   113.1   9.5   0.2413   12.38   89.55
15   (ft)   20.1   (mph)                     
                  adjusted per Hugh's latest            
RESTORING MOMENT:                              
boom                              
dia (in)   #/ft   l (ft)   #   kg         moment (#')         
2.5   2.004   7   14.0      lg boom      49.1         
2   1.264   7.2   9.1      sml boom      59.2         
2   1.264   5.5   7.0      brace      15.6         
vane                              
ga   sq ft   #/sf                        
0.063   11   0.9   9.9            84.2         
0.09   1.333333333   1.28   1.706666667            tot #'   tot #   CoG   
(5052 AL .063" ~16ga,         41.7   18.91         208.0   41.7   5.0   
strut is .090 AL ~13 GA)                              
                              
      angle (off vert)   tan   in   m   kg   #      mkg   ft#
      16   0.286745386   59.89   1.52   18.91   41.7      8.25   59.66
                           67%   
                              
                              
                              
            #/kg   2.204622622               
            kg/#   0.45359237               
            cm/in   2.54               
            m/in   0.0254               
            mph/mps   2.236936292               

Adriaan Kragten

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Re: tail hinge re-work
« Reply #4 on: September 11, 2016, 03:50:42 AM »
The moment equations of the inclined hinge main vane safety system are given in my free report KD 431 (see www.kdwindturbines.nl).

kitestrings

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Re: tail hinge re-work
« Reply #5 on: September 12, 2016, 04:05:39 PM »
Thx Adriaan.  In this case it wasn't such a matter as not knowing what the angle should be, as getting it right in the set original fabrication.  Live and (hopefully) learn.

This weekend I heated and bent the top plate.  It came out quite well I thought except for that it made a bit of a mess of my paint job.



The new hinge pin has not been cut to length, but you can see it loosely assembled in the photos with the alignment washer below the thrust bearing.  There will be a short bushing welded on top and a roll-pin fixing the hinge, then a weather cap over the top.  I like that there is a bit more clearance to the yaw tube.  The tail should come fully parallel with the blade plane when in the furled position.

I also checked the bearing end-play, and drilled six additional holes in the stator sectors using a jig I'd made.  They hadn't moved since I'd re-tightened them, but it is a pretty easy fix comparatively on the ground.  Every other sector now has two mounting holes.  Similarly every other sector has a larger bolt connecting to the stator bracket.


I also took down the stub tower and cut the base below the winch off the tube.  This will become the new top section.

~ks

SparWeb

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Re: tail hinge re-work
« Reply #6 on: September 13, 2016, 12:12:40 AM »
Hi KS.
Big improvement!
Have you also been able to change the tail's swing angle?  How far does it travel relative to the plane of the blades?
When I rebuilt the yaw mount for mine a few years ago, I made room for the tail to swing farther for a "deep" furling.

Boondocker,
Good to see you're still with us.  Got any stories to tell?
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
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kitestrings

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Re: tail hinge re-work
« Reply #7 on: September 13, 2016, 04:38:26 PM »
Thanks.  I really hadn't planned to change the swing angle.  It still stops at the same angle on the lower seat - I've forgotten, but roughly 110-115 degrees (in plan view) IIRC.


What did improve a bit is the clearance to the yaw tube.  This is because I kept the same upper hole placement, and swung the bottom out a bit further.  When in the furled position the tail vane should be parallel to the plane of the blades, or darn close to it.

Here's what I'm thinking on the bottom mount (maybe not in wood) ;):

kitestrings

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Re: tail hinge re-work
« Reply #8 on: September 13, 2016, 09:37:35 PM »
Quote
H. Piggott published 15 degrees in the Windpower Workshop book.

I should have probably mentioned that Hugh changed the method that he originally developed and published in one of the earliest books that I have (I think it is the one Boondocker references).  He talks about it here (link below).  I had this bookmarked, but couldn't seem to find it the other day.  He had some interesting comments I thought:

(the model in the discussion)


http://www.fieldlines.com/index.php/topic,146065.msg997497.html#msg997497
« Last Edit: September 13, 2016, 09:47:22 PM by kitestrings »

SparWeb

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Re: tail hinge re-work
« Reply #9 on: September 13, 2016, 11:30:09 PM »
... (maybe not in wood) ;) 

What?  You got your wood, you got your steel, you got your JB Weld, that's welded, right?  No problem!
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

Boondocker

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Re: tail hinge re-work
« Reply #10 on: September 14, 2016, 07:20:59 PM »
The copy right date on the Hugh's book is 2000, that I referenced.    I enjoyed reading Hugh's comment in the linked post

you can calculate all you like but the centre of thrust may move from the centre of the blades (which it has a perfect right to do) and you may therefore lose your offset altogether and have no way to furl thereafter

SparWeb:

I still follow the builder's post.
Recently acquired a lathe and mill, a Maximat Super 11.  I'm learning new skills by using it to make a miser stirling engine.
I'm thinking about making a Jacobs variable pitch governor, spinning an high voltage axial flux alternator, controlled with the Midnite Classic would be a fun project.

Boondocker

kitestrings

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Re: tail hinge re-work
« Reply #11 on: September 26, 2016, 04:36:21 PM »
Been away for a week of training - old dog; new tricks.

Here's the lower seat for the hinge pin fashioned out of 3/8" steel.  I think it came out pretty well.


I've cut the hinge pin to length, and mounted a bushing on the top.  This will be welded to the top piece and a roll pin will fix it to the yaw frame, and keep it from dropping.  I was hoping to find a linch pin, but the size isn't quite right.  I drilled and tapped the top for a weather cap.  I removed the old bearings and seated/pressed in a new set that does not have any of the wear from the bolt threads that I'd mentioned.  It is a much, much smoother fit now.


You can see the alignment washer on the bottom.  I've got some washers (~.060) tucked in there to give it a bit of free play at the top collar of the upper radial bearing.  Getting there, but I hope the weather holds....

~ks

kitestrings

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Re: tail hinge re-work
« Reply #12 on: October 13, 2016, 12:07:22 PM »
Progress in pictures:





kitestrings

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Re: tail hinge re-work
« Reply #13 on: October 13, 2016, 12:18:14 PM »
Here is the tower top adapted to the guyed tower, the blades, and a view from up top:




The reworked tail hinge:


...and the machine, with tail unfurled and furled positions:




I've added a polyester based shock/compression spring to soften the landing at the lower seat.  Now on to tower work.  ~ks

Bruce S

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Re: tail hinge re-work
« Reply #14 on: October 13, 2016, 01:41:36 PM »
GREAT VIEW!!
Now let me get my repelling gear and I'll be right there  8)
A kind word often goes unsaid BUT never goes unheard

SparWeb

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Re: tail hinge re-work
« Reply #15 on: October 13, 2016, 07:24:29 PM »
Another dizzying tower-top photo!
Is it the fall colours that drives people up there, or is it the rush to finish before winter!  :)
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
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Boondocker

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Re: tail hinge re-work
« Reply #16 on: October 14, 2016, 08:11:55 AM »
Certainly a nice machine!

Wondering how you keep the manual furling cable and the power wire from becoming entangled?

Please take some more photos when setting the turbine back on the tower.

kitestrings

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Re: tail hinge re-work
« Reply #17 on: October 14, 2016, 12:26:25 PM »
We plan to put it up in much the same way it went on to the stub tower (without the benefit of a ladder, and no wind I suspect).  We use two gins.  One is the standard comm's tower type with a rope thru the center to a pulley in the top.  The second is pretty heavy-duty.  It's 3" dia seamless AL tube; 3/8" wall IIRC.  This one is "L" shaped and uses a winch cable through two snatch blocks.





The electrical is dead center in the yaw head and is held by a wire-mesh strain relief.  The manual furling is away from the center a bit, and is via a light weight dyneema line.  At the bottom we have a sash weight that keeps this line taught, then it transitions to a hand-winch.  The two do twist some, but the dyneema slides very freely about the heavier SO (4 -#6 CU) cord, and periodically I unwind them both.  The trade off is not dealing with slip-rings, but it is not all pluses.







More hands are always welcome.  Although I remember in my original Sencenbaugh manual, one of the first steps was, "...clear the area of all mechanical engineers before proceeding with the installation."  I guess Jim was duly qualified.

Thanks for the encouragement.  I'll post when we go up.  ~ks

SparWeb

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Re: tail hinge re-work
« Reply #18 on: October 14, 2016, 09:05:27 PM »
Quote
...one of the first steps was, "...clear the area of all mechanical engineers before proceeding with the installation." 

We are there to help, and we insist that we know how to help, especially by showing you a better way to do THAT.
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

gsw999

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Re: tail hinge re-work
« Reply #19 on: November 30, 2016, 05:43:30 PM »
Nice work mate !