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Forum Index : Windmills : Simple Blade-Feathering Mechanism
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
This got started on another thread: http://www.thebackshed.com/Windmill/FORUM1/forum_posts.asp? TID=1813&PN=1&TPN=4 Just copy and paste; posting links for me just doesn't work. Anyway, the topic of furling (turning the blades out of the wind's flow) was being discussed and someone posted a picture (go to the link and the picture's on page 3). I saw the picture and immediately came up with an easy solution to turn the individual blades evenly without a lot of mechanical contraption. I'll build one and get back to this post from time to time. If I can, I'll post pictures, but up to now, that's been a problem too. Here's how it'll work: Each blade's shaft will be built around a fast thread, which will allow it to turn slightly about that axis when moved outward from center. As the windmill gains speed, centrifugal force will pull the blades outward against a spring. The root will be anchored via a round sleeve that has a "detent" pin, which will ride inside a fast thread. I was originally going to use a steep acme thread from a garage door opener, but now, I think I'll build a follower that will track up and down a quarter-inch or larger drill bit. I think in pictures, so this is easy for me to envision. For the rest of the crew, I'll post pictures somewhere as this project comes together. Check back every now and then. Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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gpalterpower Senior Member  Joined: 19/07/2009 Location: AustraliaPosts: 175 |
Hey McGyver how you doin,yeah really interested in this sort of stuff even though its probably a little more complicated than tail furling, but,.... I do like the concept. I was thinking of a simple way of feathering the blades out out the wind and decided to google instead. easier and less brain stress!! check out the patent storm site. just join up its free!! plenty of ideas here and more. http://www.patentstorm.us/patents/4257740/description.html your idea sounds good. you may need to go a bit chunkier than a 1/4 bit though. how about some old starter motor shafts with bendix drive as the tracker. car type starters usually have a 12mm shaft. you could try a Lucas M35 (prince of darkness)inertia starter bendix of a mini. there a bit bigger or maybe some truck stuff. about 19mm or 3/4 inch in your language All the hard work is done! regards marcus if it aint broke dont fix it!! |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
gpalterpower Thanks for the information. All my stuff is small. My windmill blades are usually no longer than 24 inches each, so I'm going to stick with small until I get things up and running. Once the basic design is settled on, building bigger would be merely a matter of stronger springs, etc. Also, I use a really little lathe. It's 12-volt as are the rest of my 'power' tools. I like little stuff. In contrast, I'm part Dutch and am physically HUGE (tall), but the rest of my world is small. Oooooh! I just took a look at that link. Way too complicated for me. Did I mention along with small stuff, I also gravitate towards simple? Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| gpalterpower Senior Member Joined: 19/07/2009 Location: AustraliaPosts: 175 |
MacGyver, Cant agree more , the simpler the better I say. Less things to go wrong. Still I idea sounds facinating as I like mechanical things. Reacon I could make one if I can see one in action. Was thinking along the lines of a centrifugal governor in a stationary engine. Will be looking forward to see some of your ideas come to life. Im part dutch too, but short....only 6 ft! Thats why Im making a 3 metre mill! Regards Marcus. if it aint broke dont fix it!! |
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| Dinges Senior Member Joined: 04/01/2008 Location: AlbaniaPosts: 510 |
MacGyver, How will you prevent the individual blades being set at different pitches? You can't rely on the springs for this, hoping that the pitch will 'automatically' be the same, as the springs are theoretically identical. You need some sort of mechanical linkage that ensures all blades will always be set at an identical pitch, or bad things will happen. Jacobs has the simplest, proven design that I know of. Some have been running for decades without maintenance. If you google the patents by Marcellus Jacobs, you'll find everything you need to know to copy it. From what I know about it, varipitch and 'simple' don't go together. Fixed pitch is as simple as possible. And we already know how much difficulties building fixed pitch windturbines create in practice for many, with blades flying off or similar mishaps. Now multiply that difficulty with a mechanism with little play and plenty stiffness, that ensures all blades will change pitch at the same time and at the same amount. It's not as simple as it seems, it's a complicated dynamic system. Not impossible to build though - Jacobs e.a. have proven this already, after many years of research and prototypes. Being the lazy bastard that I am, I'd copy 1:1 one of Jacobs' designs.... Unless you want to go all the way and use a proper design, and build it with the tight tolerances it needs, paying attention to detail, I fear such a venture will be fraught with failure. There are no easy shortcuts to varipitch windturbines. All things you can think of have probably already been tried before - google the patents, and be amazed what amazing contraptions have been already thought out - on paper. Ron and I collected the most interesting varipitch patents and published them here (www.anotherpower.com/gallery), but the information no longer seems to be there anymore. However, there was nothing there that you can't google for yourself. Unfortunately I can not even give you the interesting patent numbers, as I've thrown away all documentation in the latest move. But google patents will tell you everything you could ever want to know: http://www.google.com/patents Peter. |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Dinges [Quote] I fear such a venture will be fraught with failure Oh! Did I hear you say one of the magic words? "Can't, won't, impossible, fear" -- These are all words that spurn me on. Hide and watch. :O) Actually, I was thinking ahead of you a bit and was going to build a pitch controller on a single-blade (counter-weighted) model just to get the mechanism right. Heck, that might be the best way to go in the long run, eh? That'd work for me for sure; all I do is pump air! I'll give it a whirl sometime this week and get back here with the results. Today, I'm putting the finishing touches on a bash valve for one of my little air engines. This engine is made from a cannibalized 2-cycle weed- eater gas engine. When it's done, it'll run like a scalded dog! Off topic --I went to Mr. Jacob's place in south Fort Myers Beach, Florida in about 1972. I met a really old guy there, who was either him or his son and they had one of their original Jacob's Wind Turbines on a tower that had to be 80 feet tall! The company has since been sold. Peter: We have to figure out some way to chat back and forth without taking up forum space. Any ideas? If you are you on Facebook, look to see if there's an "invite" from me. If not, I have invited someone else in Holland with your same name. Well, you know what they say; "Nothing ventured, nothing gained!" Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| johnj Newbie  Joined: 05/04/2008 Location: DenmarkPosts: 17 |
KISS (keep it simple, sweetie) Here in Denmark, youre allowed to build a 1,1 metre diameter windmill, without seeking permission. Where I live, neighbours are are less than 25 metres away. So I want: - a mill of 1,1 metre. - a guard of a kind to protect people from flying wings - a cover for wings, to avoid annoying lightflashes. So I plan to: - fix my wings, no furling or pitch, for simplicity and robustness. - make a funnel/cone, covering perimeter of wings, and expanding after the mill. Makes the wind go faster, takes away light flash, catches flying wings. - instead of furling/pitch, the mill will get stopped in heavy winds, preferably automatic brake. - wings will be behind tower Someone stated that windmills of these small diameters, doesnt need a furling/pitch, or even a brake, as do the larger mills, does anyone have experience re this? I know this is a diifrent approach to your subject. Is it worth considering? cheers, J |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Johnj If you're worried about the blades parting and flying who-knows-where, I'd make them out of balsa and cover them with plastic film like a model glider's wing. Of course, the first bird not paying attention to where he's flying will utterly destroy the thing, but if a blade comes off it'll be no worse than a leaf falling from a tree (more or less). I make my blades of solid aluminum flat stock. I did a "parting pressure" study and the thing would have to be spinning at near light speed (more or less) before it parts. Just before aluminum parts, its tinsel strength gets extremely strong, by the way. Building a "shrouded" windmill, like you're describing will likely cause more noise than open blades. As the turbine spills wind off the back sides and tips of the blades, the air encounters obstacles and generates noise. That's exactly how a mechanical siren works. Before you start building, decide what you want out of the thing. Is it merely a pretty pinwheel or will it perform work? My windmills all pump air; I'm a bit different than most of the rest here on the 4m! As for the "light flashes"; I'm clueless to what this might be. A very large composite blade might generate static electricity, but it'll never happen with something as small as you are suggesting. Hope something here helps. Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| Dinges Senior Member Joined: 04/01/2008 Location: AlbaniaPosts: 510 |
[quote=MacGyver]I went to Mr. Jacob's place in south Fort Myers Beach, Florida in about 1972. I met a really old guy there [...] [/quote] This the man you met? http://www.jacobswind.net/MLJ%20Obit%201985.pdf Macgyver, I am not on Facebook or other similar social sites; I'm not a sociable person... ;) I saw your mail; but I fear you have mistaken me for an expert, which I am definitely not. I know only very little of varipitch mechanisms, I studied the topic for a few weeks and concluded it wasn't something I saw myself venturing into soon. Apart from that, I've mostly lost interest in the topic of windturbines as well; I still visit this forum mostly because of all the people I know and want to keep up to date on what they do, but you may have noticed that the majority of my posts/comments have little to do with wind anymore. So, in short, I'll respond when I feel there's something I can contribute, but I'm no longer interested enough to study and read up on the subject as I once did. That, plus the fact that there are many more knowledgeable people on this forum (though some mostly lurk) who could chime in if you posted your problems, solutions, findings, results etc. here in this forum; it's not a 'waste of forum space', as you say; it's actually the reason for the existence of forums such as these, where ideas can be discussed publicly. Many eyes looking at it, and hearing from different viewpoints. Peer review. What may interest you too: there's another Dutchman, Jacques Mattheij (Nick 'Jacquesm' on Fieldlines forum), who used to live in Canada, who has experimented with varipitch mechanisms too. You should really read his stories about the problems he encountered: http://www.fieldlines.com/story/2004/9/9/203815/7588 (that's not really the story I was looking for; it only contains one lousy picture of his varipitch mechanism, there should be a much better story somewhere on FL with much better pictures and explanations) His other stories, also interesting: http://www.fieldlines.com/user/jacquesm/stories For some reason I can't really find the story of his varipitch machine I was looking for; not sure whether it's my searching skills or problems with the fieldlines forum. The story may have been in his diary, but I don't get to see his diaries or photo files anymore. Peter. Edit: found the link I was looking for: http://www.fieldlines.com/story/2004/11/10/172439/76 also see: http://www.fieldlines.com/story/2004/11/11/8830/1379 http://www.fieldlines.com/story/2004/12/12/24748/545 http://www.fieldlines.com/story/2004/11/24/21121/823 |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Dinges: [Quote]This the man you met? [/Quote] Yup! That'd be him. As for the other stuff, I'm a little disappointed you're not doing windmills much any more. It's kind of a "Dutch" thing, if you know what I mean. You seem to be much like my son, the PhD Aeronautical Engineer in that everything you type looks like it came straight out of a textbook. Don't sell yourself short, you're plenty "expert" for most of us here and me especially! As for the veripitch stuff, it'll be just another experiment. My whole life has been an experimental 'work in progress' so to speak. I don't like copying other folks' work; i'd rather come up with my own ideas and try them. If they work, all that much better. If they don't work, at least I get the honor of truthfully stating, "Been there, done that!". In a similar vein as Thomas Edison, I don't consider it a failure when something doesn't work the way I envisioned it should. Like Tom said, "It's not that I failed several thousand times; it's more like I found out several thousand ways a light bulb won't work, that's all." I'll look at the links you provided; thanks. As for the Fieldlines Forum, it looks a bit 'technical' for my 1940's brain. I'm more a 'nuts-&-bolts' kind of guy; mechanical and all. I'll have to think about it before signing up for that one my friend. Thanks for your input. EDIT: Wouldn't you know it? I was reading your friend's article and recognized a very simple solution to his yaw dilemma. If you haven't already guessed it; I'm now a forum member on Fieldlines.com; Handle is MacGyver there too! Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| Janne Senior Member Joined: 20/06/2008 Location: FinlandPosts: 121 |
The pitch control mechanisms are mostly very simple and easy in paper(and even in small scale), but the problem comes implying the system in the large scale. The problems arise near the same prop sizes where pitch contol becomes preferred over other methods of furling. With 9+ meters of rotor diameter, there is a whole lot of proper engineering to be done, before we have a reliable feathering system. Getting proper blade bearings to handle the constantly varying stress, but turn freely at the same time, fixing a reliable mechanism to keep the blades as sync, damping the mechanism... It can be done, but in needs good engineering to work, why many choose the "normal" furling, it can be much more crude and still work great. If at first you don't succeed, try again. My projects |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Janne I hear you. On a lighter note, I examined a Jacobs wind turbine up close one day in Florida many years ago and it had three little weights supported on shafts attached to a spring each and a beveled gear. Each blade was geared to the other two, so when one moved, they all moved. As the thing spun, the weights would move outward by centrifugal force and in so doing, create leverage through the attaching lever and gear turning it slightly and pitching the blade(s). Even though it was very simple, the thing worked and worked well. Several of these machines ran for years with no service. My design is about as simple, though I have not incorporated any linkage between blades, which seems to be something I should think about doing by the way the comments are flying here. Thanks for your input. Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Variable-Pitch Blade Update: I've researched this "variable-pitch blade" topic a bit since my original post and the trend in thought seems to be that as each blade responds to the stimulus required to make it change pitch, the tendency is for each blade to "hunt" on its own and not work in conjunction with the rest of the blades on the turbine. I did a little mock up of the project in my shop and have decided to work this in reverse. What I mean is, I'm going to set my static (at rest) pitch at 45 degrees. My windmills pump air and start under load, so I need all the torque I can get right from the git-go. To that end, I'm starting out at full pitch and set the variable-pitch governor to "feather-to-stall". Instead of acting as an over-speed brake, my variable-pitch system will make things speed up to maximum. Doing it this way will make the system constantly hunt for torque instead of speed and I don't think it will be as finicky as it would be if I were using the pitch control as a brake. Time will tell, eh? As soon as I have a working model, I'll post pictures or a movie somewhere (You Tube?). I'll keep everyone here in the loop. Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Update: This post is just to let the rest of the crew know I'm working on getting this thing operational. Long story short: I spent the first half of the day machining a part that I should have used a special mandrel to make, but thought I could cheat it and subsequently ruined the part, then spent the other half of the day making that special arbor so I don't ruin the next one. There was a strange little fellow lurking in the corner of my shop. I believe he said his name was Murphy! Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
It would be good to see your progress with some pictures, as most on this site enjoy seeing what is in the process of being built by other members ..... PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| gpalterpower Senior Member Joined: 19/07/2009 Location: AustraliaPosts: 175 |
Hi MacGyver, Gotta keep a look out for that little 'M' guy. he will stuff thing up for you. only yesterday I was machining a small spacer for my f&p shaft. wanted a neat fit but you guessed it. cut too much!!! had to start again. Will also be interested in watching your progress. I have also been thinking about how to develop some sort of feathering mechanism. After looking at some of the fieldlines stories suggested by Dinges it all looks a lot clearer now. I wont say simple, but when you can see one it makes it a lot easer to make one. Still..... there would be some tinkering, but I love the idea. So... with the one you are developing , you are starting from a 45 degree attack angle as rest, then turning the blades to full attack and finally flat to the wind for braking, or the other way around? Marcus. if it aint broke dont fix it!! |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
gpalterpower My little windmills pump air. If there is already pressure in the system, it means they have to start with a load. For that reason, I set the static pitch at 45 degrees, which is maximum attack angle. As the thing starts spinning faster and faster, the idea is to have the centrifugal force on the blades move them towards the outside against a spring. As that happens, in my case, the angle of attack will lessen until it reaches a maximum of about 15 degrees. Once the thing has overcome the moment of inertia, I want all the speed I can muster. Each time the windmill shaft rotates, a cam pumps one little squirt of air into the system and so on. If the wind flow falls off (as it does) I want the blades to return to a static attack angle closer to 45 degrees. This allows them to have more torque in a lighter wind. I'm using a large drill bit as the steep-pitch runway. The blade is mounted on a collar that has a detent down in the open area of the drill bit. As the blade moves outward, the little pin trapped inside the bit forces it to rotate slightly as it moves out, thus augmenting the pitch. Hope that clarifies things a bit. It's going to be a week or three until this thing is up and running. Unfortunately for this project at least, I came across plans for a really sexy little oscillating engine that I just MUST build! Building stuff is my drug of choice! Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| gpalterpower Senior Member Joined: 19/07/2009 Location: AustraliaPosts: 175 |
Thanks McGyver, Sounds clever.  I'll be waiting to view the pics or vid of your device. All the best with your sexy oscillating enging. Some pics of that wont go astray either!
Marcus if it aint broke dont fix it!! |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi there, One of the simpler systems i have come across that was in use on a large turbine is here at fieldlines.Link Here One hell of a turbine to! Still waiting for some photos of what you are up to with your idea. One question? if the water goes down the plug hole the opersite way in the USA, do your turbines spin backwards to?  Sometimes it just works |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Fillm et al: RE: Pictures For some reason, I am unable to post pictures here. That goes for links as well as a number of other cool things. Glen seems to think it's my browser trying to interject "corrections" to the html or something like that, but it remains virtually impossible for me to post a picture. So far, the only thing that's worked out is my avatar photo! What I think I'll do is make a special page at the back of my hydroponics Web site and just post the link information here on the 4m. That way, folks can take a look at what I'm talking about. Like I've said before, I think in pictures and assume everyone else does too. I know that's not the case, so a photo here or there would be a great advantage for the rest of the crew here. Along with a gerzillion other things; "I'm working on it". Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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