Author Topic: Active Pitchcontrol  (Read 331762 times)

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mbouwer

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Re: Active Pitchcontrol
« Reply #297 on: September 24, 2012, 07:25:35 AM »
Windmillfriends,

Turbine engineers often have tried to start with available parts.
After years of searching for improvement came the design of the large diameter direct drive generator.
Besides that: The larger the diameter of the wings the more energy you can generate.

I would like to point the following question:

Isn't it logical enlarging the diameter of the bearing, and use a single main bearing ?

rgds Rinus

Frank S

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Re: Active Pitchcontrol
« Reply #298 on: September 24, 2012, 08:52:59 AM »
I'l answer that one often times what appears to be logical on paper or even table talk does not always equate to the most economical nor the most suitable for a given situation . it boils down to a matter of choice which road do I wish to travel on the one that has long gentle sloping hills and straight a ways and gentle large radius turns or the one in which has constant switch backs steep ups and downs, if I choose the former I will need something to keep me awake with the latter I will be too busy to fall asleep However the road with the switch backs and steep hills is 5 times shorter. Can I arrive sooner taking the longer road or the shorter more difficult one.
 it is the same way with wind turbines or wind generators. the 2 are neither the same thing nor are  they much different in the end.
 A large single bearing may look inviting and ultimately could turn out to be a reasonable choice.
 doing it with one single row of balls may not be the solution doing it with 2 or 3 rows may not either it may be found that balls should not be used at all but rather sue short rollers with a diameter the same as their length Size the bearing so that an equal number may be placed at 90degree angles to one another now you have a single double row bearing that functions like a pair of tapered roller bearings back to back the groves now "V"s and have 2 flat surfaces by which the rollers roll upon.
 we think OMG we have come up with the perfect bearing design it can take care of radial thrust and angular moment loading all at the same time and could  have  much tighter tolerances. BUT does IT?
 is it just yet another road to travel upon?
  I have seen a few slew bearings designed just that way used on some huge equipment. Had I had the opportunity to ask the designing engineer who came up with the idea. I would have asked what about the interference angles between the squareness of the rollers and the surface of the "V" groves
 was this a another trade off? there wold have been only one possible answer Yes.
 all bearings have at least 3 things in common they are a trade off compromise solution, they function better in one plane than another,  they work better when in pairs
I live so far outside of the box, when I die they will stretch my carcass over the coffin

Frank S

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Re: Active Pitchcontrol
« Reply #299 on: September 24, 2012, 09:39:20 AM »
Another thing a builder can do in the design of their turbine is to make a "V" grove outer race then make a mated pair of inner races with the piloting boss like one of the bearing drawings I showed  use a stack of shim stock to space the inner race then use round balls remove or add shims until the tightest fit is accomplished but still loose enough to rotate freely. the balls are only going to touch in 4 points no matter if the grove is round or "V"  and a ball is just as happy rolling in a "V" as it is in a radius.
 This way you may be able to hold costs of machining down Hardening a flat surface is easy to see and check the results as the groves wear shims can be removed to hold tolerance
 There are any number of different way to look at a problem and equally as many way to solve them.
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mbouwer

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Re: Active Pitchcontrol
« Reply #300 on: September 24, 2012, 02:29:41 PM »
Windmillfriends,

To show in what direction we want to look " out of the box " we made this lightweight ajustable two rows angular contactbearing. ( 2 x 24 balls )
But we think two rows is not really an improvement of the bearing we showed in reply #263 of this topic.

Rgds. Rinus

fabricator

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Re: Active Pitchcontrol
« Reply #301 on: September 24, 2012, 05:10:14 PM »
That looks nice, is it heavy enough to take the beating though?
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

mbouwer

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Re: Active Pitchcontrol
« Reply #302 on: September 25, 2012, 04:53:06 AM »
Hi Fabricator,

The version in reply #300 was only intended to show in what direction we think to construct a leight weight single main bearing.
 
Our intention is to find windmill builders who think along.

rgds Rinus

Frank S

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Re: Active Pitchcontrol
« Reply #303 on: September 25, 2012, 06:02:46 AM »
I'm done we have hijacked Franz thread long enough none of this bearing talk has anything to do with his or anyone else's active pitch control.
 this discussion has strayed into another realm even though it still has subject matter relative to wind generators
 any more contemplation of design for  bearings should be in a thread about bearings unless it is about bearings for the blade mounting

 I apologize to Franz and others for contributing to the wayward stray of this thread 
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midwoud1

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Re: Active Pitchcontrol
« Reply #304 on: September 25, 2012, 07:20:35 AM »
Frank and Rinus.
There is no problem of hijacking the topic.
You are welcome.
I'm interested in all inovation and improvements of our windturbines.
The big bearing might be a long prayer but on a day there is a solution.

Rgds.  - Frans -

Frank S

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Re: Active Pitchcontrol
« Reply #305 on: September 25, 2012, 08:24:46 AM »
Franz what I was thinking of is future seekers of info might be searching for a how to or an alternative to use for their main bearings
 the large diameter one has some merits in that it allows the through hole to be what ever you design in
 the car hub style with the small bearings has its limitations but affords the use of recycled scrap car parts
 should someone be just a little industrious and use the assembly from a front wheel drive vehicle this has 2several merits of its own. First it would have a hollow hub by which an activation plunger could pass through the hole where the axle would have been
 another is it has larger bearings offering a better angular moment control it will withstand thrust as well and obviously radial
 next it is off the shelf technology easily replaceable.
 the added plus just like the regular trailer type hub it can be found as scrap
 Let's carry this one step further and use a hub from a rear end of a light truck with a full floating axle
  right away we can see more benefits here in that the housing tube can be mounting member just weld a vertical pipe to it and you now have a full unit for both the yaw mount and the turbine mount.
 the hub has generally from 6 to 10 strong studs depending on size. a very large plate can be mounted for the blades or the generator
 if we get into the really large truck hubs like the Mercedes with the planetary we can use the hub the housing tube and with a little modification even use the axle by mounting a bearing in the opposite end of the tube then mount the rotor on the axle to give us a gear up now we have about a 1 to 2 speed increase  the planet plate can be changed a secondary gear set could be used with lighter duty gears allowing enough room in the hub to make it a double gear set possibly going to 1 to 5 or more  Of course using that set up kills a plunger driven active pitch control unless a hollow axle was used.
 as I have said before there are as many ways to design the main bearing assembly as there are folks who chose to build turbines.
 I like the double bearing pic of Rimus I question its strength without knowing the scale or thickness of materials
When i see something that looks like stamped plate with small stay rods for supports I have to think of an item being on the extreme end of being optimized for weight.
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fabricator

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Re: Active Pitchcontrol
« Reply #306 on: September 25, 2012, 08:48:19 AM »
Hi Fabricator,

The version in reply #300 was only intended to show in what direction we think to construct a leight weight single main bearing.
 
Our intention is to find windmill builders who think along.

rgds Rinus

Rinus, if you are looking for enough home DIY windmill people to make it worth having some actual bearing manufacturer build those bearings it would take a half million or so to make it worth while for a manufacturer.
IMHO you are going to have to use an existing bearing or have a machine shop build them for you.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

mbouwer

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Re: Active Pitchcontrol
« Reply #307 on: September 25, 2012, 04:14:25 PM »
Hi Frank S,
We really appriciate your explanation, and we share the same thoughts about a frontwheel drive hub.
Mainly the limitations of the small diameter of the hollow hub hinder us.
rgds Rinus

Frank S

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Re: Active Pitchcontrol
« Reply #308 on: September 25, 2012, 06:22:37 PM »
yes well this would largely depend on the make or models some are larger than others and the splines can be machined out as well allowing the bores to be increased in some instances as much as  double the original diameters.
 A plunger shaft strong enough to operate a ptich control system such as Franz's unit needs to be only about 1" in diameter
 A 5/8" 70KSI rod 25" long can achieve 1000Lb thrust before buckling a 1" can be 60" long for 1000lb or 25" long for 6000lbs
Step it up to 2" and we are talking close to 50,000 at 35" long
 if you designed a pitch control to be in the pull mode then those figures would be re calculated to sectional area times tensile of the material
 loads are meant to represent approximate values and are not to be considered as relative absolutes, eccentric loading reduces values.
I live so far outside of the box, when I die they will stretch my carcass over the coffin

fabricator

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Re: Active Pitchcontrol
« Reply #309 on: September 25, 2012, 07:06:25 PM »
I think Frans is only using something like a 1/4" push rod, that hub could be annealed and bored to twice that inside diameter.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

Frank S

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Re: Active Pitchcontrol
« Reply #310 on: September 25, 2012, 08:16:55 PM »
Sometimes on these long threads it is well worth going all the way back to the beginning and take a look see at the pics or read some of the posts
 Lots of evolution and info in them

 
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midwoud1

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Re: Active Pitchcontrol
« Reply #311 on: September 26, 2012, 01:37:13 AM »
The pushrod of the 10 footer is 6 mm dia. x length 450 mm ( brass )
The 12 footer design has 8 mm x 450 mm ( C 45 )
It's very light running back and forward even at high speed prop.
The blade shafts in the center of gravity point of the blade profile.
I don't know the figures but increasing current draw is hardly to see on the actuator power-supply.

 - Frans -

mbouwer

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Re: Active Pitchcontrol
« Reply #312 on: September 26, 2012, 04:31:36 PM »
Windmillfriends,

After the Gewiekste kick off meeting to start building a working model of a modern professional turbine, we started making a console out of old iron to place the top part of the mast on.

Intention: exchange parts, information and ideas.

Rgds Rinus


fabricator

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Re: Active Pitchcontrol
« Reply #313 on: September 26, 2012, 05:04:45 PM »
My question is why? Is this machine meant to produce power or just be a model? If it is meant to be a real working turbine why does it matter that it looks like a professional turbine, Frans turbine is producing power every day and can be built at a fraction of the cost of your proposed model. Take Chris Olsons geared machines for example, the don't look like the big machines but they produce kWh every day.
I guess I just don't see it as practicle to design for form instead of function.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

mbouwer

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Re: Active Pitchcontrol
« Reply #314 on: September 26, 2012, 06:07:34 PM »
Hi fabricator,

Via our site and in conversations, we become more and more firm believers that people in Holland get inspired by the impressive windturbines they see around them.
If they live in the countryside and have undisturbed wind stream, some would like a small turbine on their domain.
It has to be safe, easily controllable (active pitch), dependable and they like "high tech"

If I see the pictures of the turbine you have so nicely composed I can put myself in your place.
Although we look in a somewhat other direction I think we have much in common too.

Rgds Rinus


fabricator

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Re: Active Pitchcontrol
« Reply #315 on: September 26, 2012, 06:44:24 PM »
Fair enough, good luck.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

mbouwer

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Re: Active Pitchcontrol
« Reply #316 on: September 28, 2012, 04:49:20 PM »
windmillfriends,

We made the mast upperpart and fitted it on the console.
with 12 bolts M 5  ( stc 120)
If anyone in our region, wo has no facility to weld, would like to build along with us we can take care of the welding.
rgds Rinus.


mbouwer

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Re: Active Pitchcontrol
« Reply #317 on: October 12, 2012, 06:37:06 AM »
Windmillfriends,

We want to continue describing this working together windmillbuildingproject on the Dutch forum:
 http://www.ecologieforum.eu/viewforum.php?f=23&sid=1e32a820f5db9a164fb31be66cf97049

In cooperation with www.gewiekste.nl

Language is Dutch. Ask us if you want a translation.

Regards Rinus.

midwoud1

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Re: Active Pitchcontrol
« Reply #318 on: November 09, 2012, 04:34:32 PM »

  Windtunnel test Piggott windgenerator 1,80mtr at OJF (OpenJetFacility) TU  Delft.
                                         Netherlands

          http://vimeo.com/33005718

SparWeb

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Re: Active Pitchcontrol
« Reply #319 on: November 10, 2012, 12:41:52 AM »
I most liked the part of the video with it furling.  Tail still mostly downwind, blade disk furled back about 45 degrees.
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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midwoud1

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Re: Active Pitchcontrol
« Reply #320 on: November 26, 2012, 03:46:45 PM »
25-Nov-2012
Storm  7-8 Bft,  Gusts 9 Bft.
Blades feathered  .
Fully charged battery bank.
No smoke.
- Frans -

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Re: Active Pitchcontrol
« Reply #321 on: November 26, 2012, 05:52:15 PM »
That thing is really cool Frans, very nicely done.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

SparWeb

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Re: Active Pitchcontrol
« Reply #322 on: November 28, 2012, 09:54:25 PM »
In airplane-talk, we call that "fully-feathered".

Excellent.
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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mbouwer

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Re: Active Pitchcontrol
« Reply #323 on: December 30, 2012, 12:06:57 PM »
Hey Frans,

 We really are curious after your 2013 improvements.

Regards Rinus

midwoud1

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Re: Active Pitchcontrol
« Reply #324 on: January 16, 2013, 03:08:11 PM »
What is the best blade airfoil ?
I'm working many years with Clark-Y ,but I see different ones good working as well.
The Clark-Y is low noise in normal working condition with a sharp trailing edge.
But in higher wind 15 m/sec.with auto-blade pitch 8 deg. there is stall-effect and noise at 350 rpm.
Wondering if other airfoils have that more or less.

Rgds. Frans.

SparWeb

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Re: Active Pitchcontrol
« Reply #325 on: January 18, 2013, 01:02:56 AM »
"Don't get me started"  (that's a common english phrase that may not translate well.  It means that you will provoke much heated debate, just for asking!)

I've often said that too much importance is put upon selecting the perfect airfoil, but for small backyard projects such as ours the result is hard to detect.  Using the Clark Y or the NACA is perfectly fine.  These are tried-and-true airfoils, easy to make, and have thick cross-sections for strength.  You make your life complicated with the cambered airfoils, unless you are also ready to commit to making them in a somewhat complicated way (though if you do have a table saw or a router table available, then don't let this stop you.
In your case, Frans, you have electronics that monitor the turbine, and a pitch control system that responds to wind speed, so you are in a much better position than usual to measure and check these assumptions.

I believe the effort of making complex blade airfoils such as the SERI types is a total waste on a home-built wind turbine.  Second, the only airfoil types to seriously consider are the ones designed to be effective at low Reynold's numbers (that aerodynamic terminology for "small scale").  Other than that, you have other things to do that are more important than the airfoil shape. 

I usually see, in photos on this site, variations in profile that can add up to several millimeters, or in other words many % of the airfoil chord.  In comparison, the difference between the Clary Y and NACA 4412 is also just a few % of the chord, in scale.  To me, that means that the airfoils often used are not highly accurate reproductions of the "perfect" shape.  The builder may have good things to say about the blades, but the airfoil isn't as true as he thinks.

Another fact is that the aerodynamic smoothness of the airfoil, which you should be sanding and finishing with paint or other protection, will be the strongest factor in the air drag.  Since drag steals torque from the blades, any effort at reducing drag will pay handsomely in efficiency.  Since sanding and painting should take about an hour or two of work, I would venture that the value of that time spent is worth 10 times the value of selecting a "perfect" airfoil.  That task can take days, and the benefit will be smaller.

Those are just my general opinions about what's important to me, when making blades.  Back to your problem:

Have you tried adjusting the pitch angle?
Is it the 12-foot or 10-foot blades that are giving you this trouble?  Stalling always makes noise.
Is the "stall-effect" you mention an abrupt, cyclical one, or does it just rob power away?  Shouldn't the blades be feathering at that wind speed?  Have you compared the pitch of the blade to the inflow angle of the wind to find an approximate angle of attack?

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

midwoud1

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Re: Active Pitchcontrol
« Reply #326 on: January 18, 2013, 01:25:57 PM »
SparWeb.
Thank you for the info. Most of us have Clark-Y (Hugh) ,NACA 4412, GOE 222 airfoils(Royalwdg)
I think Chris has S 809 . I red in previous posts that stall resonance can cause damage to the generator construction. There is no flutter, so no problem. All working fine.Balance and track.
Have a blade set of 12 foot (model Piggott with a streamlined trailing edge).
and a blade set 10 foot with half the root thickness wich is running now.
At 350 Rpm the blade-pitch is activated 1 step 0,5sec , with increasing wind another step and that's the moment of stall. 1 step is about 6 degrees.
With decreasing wind below 250 Rpm its going the otherway.
In storm or full batteries there is  auto or manual full feathered prop.
There is a slight resonance in the generator at 200 Rpm ,but that disappears at higher Rpm ,I think most us have it.

Rgds. - Frans -
« Last Edit: January 18, 2013, 01:35:31 PM by midwoud1 »

ChrisOlson

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Re: Active Pitchcontrol
« Reply #327 on: January 18, 2013, 03:33:40 PM »
Thank you for the info. Most of us have Clark-Y (Hugh) ,NACA 4412, GOE 222 airfoils(Royalwdg)
I think Chris has S 809

I am flying a set of S809's at present but they are very noisy.  The turbine that has them will be getting a new set of NACA 4415's in the next couple of weeks.
--
Chris

gww

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Re: Active Pitchcontrol
« Reply #328 on: January 18, 2013, 03:54:40 PM »
I am at 40' now and my turbine acts exactly like yours.  40' doesn't even get over my small trees.


cheers
gww

midwoud1

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Re: Active Pitchcontrol
« Reply #329 on: January 18, 2013, 04:53:35 PM »
The only NACA 4415 I have is the wing of my WW2  Spitfire.
Good flying performance.

Rgds -Frans-