 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Windmills : Folding Tower
Page 1 of 2   |
|||||
| Author | Message | ||||
MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Crew I was trying to figure out where to put this and I settled in on "Windmills"; maybe it should be in "Other Stuff" but since it has to do so much with turbines, I stuck it here. Glen: If you want to move it; your call. Anyway, there's a guy in my little home town that makes these things and HERE is his Web site. I have only given the Web site a cursory look-see and don't know much more about it than what shows on the main page. Apparently, by the little moving picture, the tower folds in the middle, allowing one to work on the turbine (albeit upside down) a little closer to the ground, making it a bit more accessible. I don't know costs or anything, just thought it was cool and got their permission to drop a link here on the 4m. Edit: typo . . . . . Mac 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 |
||||
gsw999 Newbie  Joined: 22/01/2011 Location: United KingdomPosts: 19 |
Looks pretty cool, the guy obviously knows his stuff! i am not interested in giving my hard earned money to corrupt "leaders" to pour down the drain. |
||||
| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Mack It looks neat and thats a big turbine mounted on it. Bob Foolin Around |
||||
Oscar4u Regular Member  Joined: 23/02/2011 Location: New ZealandPosts: 42 |
A grand design how silly an idea is it to have a ladder on the inside of the tower and a couple of boards ontop of the mill to work of? Is material behind the blades likely to affect aerodynamics? Cheers Oscar Oscar4u - for all your rotary cowshed repairs |
||||
| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Hi Oscar,,, Welcome to the forum. I was surprised at your comments, have you any experience with towers or windgenerators in general, Sorry , not seen your name "oscar" recently , but I may be wrong.. The construction looks very professional to me from the posting ... OK, so now it's over to you ,,, You describe what You would do and we'll all see if it's crediable or not ,..( I was going to use another phase ,but I'll bite my lip) Bruce. Bushboy |
||||
shawn Senior Member  Joined: 30/03/2010 Location: New ZealandPosts: 210 |
Mac thats a great looking tower. Just to hijack the thread a little  thinking out loud here but to add a cheap tower possibilty
how about two power poles (free) side by side then hinge a pipe at the top between them to get the height which could also bring the mill down for work Hmmmm don't shoot me... but i am sure this could work. |
||||
| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Shawn You mean something like THIS? . . . . . Mac 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 |
||||
| shawn Senior Member Joined: 30/03/2010 Location: New ZealandPosts: 210 |
year thats kinda what i was thinking just the two poles at the bottom could be old telegraph poles and the middle pole be around 150/200 mm then you could add wires and get a good high tower for a little money for the center pole and guy wires. if you didn't go to high with the center pole you would not need guy wires building it would of course take as long as others though, could even take longer... |
||||
| Oscar4u Regular Member Joined: 23/02/2011 Location: New ZealandPosts: 42 |
Hello Bruce yes I am green as they come. I built an water wind pump and tower twelve years ago and have had much pleasure from that. I built the tower, head, blades and the pump itself. Have dreamt of building a generating mill for a decade but never got around to it and lack lots of knowledge. I have lots of three phase gear so going of grid is not worth the effort for me. I hope to pump back in to the grid to get some use out of the new toy to be. The waterpump tower is half as wide as hight with a ton of concrete to hold it down. Might do something similar this time. My figureing is that it is largely the same ammount of effort to make something large as small. I was planning on mounting the three blades on a car rim and running a car diff as the head, using the 90 degrees to face down and have a very long drive shaft so the gennie is close to the ground. Have very little idea what to use for gennie. I read with much amusement the ten page post of some porche driving dude that was was going to make a 10 kw vertical mill a couple of years ago on this forum. Going big obviously brings its own problems! I am concerned about the safety of the mill as well as myself. I figured on makeing a ladder inside the tower to get to the top and haveing a plateau there to work on. To protect the mill thought of makeing a govenor to feather the blades. Other members on the forum have told me I am nuts contemplating going down the feathering road. Also figure the gennie needs to to too big rather then too small to reduce chances of burning out. Am very impressed with ozules chainsaw blades. Would like to have a crack at that. Possibly make three meter blades and might have a spar to increase the swept area. Lots of possibilities and few certainties. Thanks for reading all this drivel. Cheers Oscar Oscar4u - for all your rotary cowshed repairs |
||||
| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Oscar4u Welcome to the 4m. The 90* car differential idea is great imaginative thinking on your part. Only trouble is; it won't work. Depending on how the gearing is set up in the "hog's head" (American word for differential) as the wind turns the turbine against the load, the gears tend to "walk" the whole thing about the vertical axis, turning things out of the wind flow. A HUGE tail feather will counter this, but the bottom line is gearing robs power and is not a good idea. The energy density of moving air is small and you have to be careful to extract as much as you can with as little effort. Anything that stands in the way, like friction or gears, will reduce your already meager power expectancy of wind. I have designed and built a few "feathering" designs, but to tell you the truth, unless your turbine is ginormous (really big) it's a waste of time. The extra gains do not offset the amount of effort as well as the amount of future problems associated with all the moving parts of a feathering system. Marcellus Jacobs used a handsome feathering device on his mills, but his blades were really long and narrow. For those of us just tinkering around with stuff, it's fun, but I'm sorry to say also a bit pointless. You are better off sticking to a proven design at least for your first genuine build. I am the unofficial king of doing things the hard way, so I'm speaking from experience. 99% of the "toys" I build don't work in the field the way they "should have" on paper. Apparently, we are truly not living in a perfect world! I've been on a 6-month hiatus, but will crank things up in less than one month. You are welcome to follow my follies and make necessary changes as you see fit. "Show & tell" was my favorite subject in school and I try to post pictures and accompany that with clear instructions, so others don't have to stumble into the same ditch. I should add here that I post failures as well as success stories; how's anyone gonna learn if we lie about our efforts? All in all, this is just "for fun" for most of us. A lot of us are retired, including me as of this morning!! I'm looking forward to this retirement after 47 years of being a plumber (I started when I was 15). Building wind gizmos sure beats hell out of playing shuffle board! . . . . . Mac 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 |
||||
| Oscar4u Regular Member Joined: 23/02/2011 Location: New ZealandPosts: 42 |
Hello Mac congratulations on retirement. I am worried that when I am your age the government will have shifted retirement to 99. Had thought of your problem already and it would be easy to run a pipe down from the head with the driveshaft turning in it. This means the genie would turn with the mill and overcome this problem. Part of me says it is a lot of work for nothing but would make some work easier and safer. unfortunately i have to accept what shawn and you say about feathering. Sometimes though I do things because i can and as a challange. You might be the unofficial king of doing it the hard way in the Northern hemisphere but I hold that title in the Southern Hemisphere!!! How stupid or inefficient an idea is it to set the blades out from the hub a couple of meters? One would need to gear it up, which would decrease efficiency but I figure the extra swept area might make up for those losses. is there such thing as a free lunch? My understanding on blade design, blade angle, tsr and blah blah blah is nil. thanks very much Oscar Oscar4u - for all your rotary cowshed repairs |
||||
| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Oscar4u Thanks for the retirement compliment. I figured I'd get it while I could! As for your running the shaft to the ground idea; don't. I did this about 40 years ago using an outboard motor as the device to change directions and all the thing did was precess about the top of the tower no matter how big I made the tail; just doesn't work -- sorry. As for gearing, again, don't. Gears rob power and there are simple and efficient methods already tried and trued that will let you turn a very robust generator (or alternator as it were) with no load at start-up. This lets you out of having to use gears as the turbine will spin up to the alternator's operating speed without load and once things kick in (called "cut-in") everything is spinning at the proper speed. Placing the blades on little posts is called using a "stand-off". It is a common practice enabling the surface area facing the wind to be increased without having to build ginormous (really big) blades. It offers less resistance at the hub, which some believe allows the air to flow through the turbine with greater ease (and others think that's a crock) but at any rate it's done all the time. The "purists" shun the practice based on aesthetics; it looks like hell. I say "what the hell!" and do it anyway; I don't care what it looks like. By the way, the amount of power available to be extracted from flowing wind is directly proportional to the cross section of the swept area (area of your turbine). This means standing the blades off a foot will greatly increase your turbine's "footprint" and your power available goes up exponentially! I make my blades from Coroflute plastic and have already placed a tutorial here on the 4m. Check it out if you want. These blades use stand-offs and are very light and robust. Several folks on the 4m have commented that they are not sure the blades will hold up in strong winds, but if the "spar" (the stick down the inside of the blade from one end to the other) is made of aircraft-quality aluminum tubing, it'll withstand a gale with no problem whatsoever. If the blades were to be longer than 8 feet, there'd be a problem in that the sheets of Coroflute are manufactured only in 8-foot lengths to the best of my knowledge. The stuff holds together like welded steel with CA (cyano-acrylate) glues and are easy to build. And no, there are no free lunches in either hemisphere. Hope this helps you on your journey. . . . . . Mac 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 |
||||
| Oscar4u Regular Member Joined: 23/02/2011 Location: New ZealandPosts: 42 |
Hello Mac The only looks that worry me are what I see in the mirror. Having standof blades I could live with happily. I have seen your coroflute blades tutorial previously before, although I did not take them seriously. Accepting they need a serious inside spar do you think they would last reasonably long in a gale? I read them as being a toy more then a tool. My appologies for that. What is the longest they have been flown before? Also thought of trying to source some 300dia plastic pipe with about fifteen mm wall and cutting that length ways.Nearby a mate of mine is using 150 mm pvc with moderate sucess. Figured on copying that and scaling it up. My dreams were to have about a sevenish meter dia blades (with presumably a stand off in the middle). With that size blade I figured it would turn relatively slowly (would you hazard a guess at the rpm ?). For arguments sake I would need a 5kw alternator??? What for an alternator would work at that speed? Thankyou very much for your help. Best wishes Oscar Oscar4u - for all your rotary cowshed repairs |
||||
| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Oscar Have a look at Altons calculator it will give you some idea of disk size in relation to your available wind speed for your 5 KW, However I would suggest you start with a smaller unit first to get some experience in wind turbines. http://www.alton-moore.net/wind_calculations.php I have tried several PVC pipe blade sets and found them very inefficient and poor at starting, you would be better off making a set of wooden blades. A 6 meter blade set would give your 5KW at 10 MS. One problem with the blades going slow is to find a slow speed alternator to match the rotation speed. if you decide to gear up speed I would suggest a Gates tooth belt as they are more efficient than gears and don't have lubrication problems. All the best Bob Foolin Around |
||||
| Oscar4u Regular Member Joined: 23/02/2011 Location: New ZealandPosts: 42 |
Hello Bob That was an interesting link. The KW output at blades column did not work for me. Thankyou for posting that link. I have sort of got my heart set on a bigger set rather then smaller. There is every chance I will get my fingers burnt somehow but that is part of the learning curve. Am very keen on oztules chainsaw blades. Making them bigger would not be a great effort. If hypothetically I end up with 60 rpm do I go for (if there is such a thing) a slow alternator, or how much do I try to gear it up? My gueses are I have to gear it up for the bigger blades.I figure if I have a larger alternator then the blades output it would reduce the chances of burnout. I suppose it would run less efficient however? That gates tooth belt does sound painless. Thankyou very much for your time and advice. Best wishes Oscar Oscar4u - for all your rotary cowshed repairs |
||||
| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Oscar I have plans for a 5KV unit using a 10 HP 3 phase gear reduction Motor that is feasible if you have the wind available but it is a grid feed unit so may not be usable for your application. I also had a similar idea using two aircraft generators, but where I am the wind isn't enough to justify the effort to do that. You would need enough wind to sustain 120 rpm on a set of 24 foot blades. I have several 35 KVA alternators but they would become a major job as they weigh over 1000 kg and require 750 rpm and 1500 rpm respectively. Maybe I need to shift to a high wind area to use them but would only be useful for grid feed as to big for home use. All the best Bob Foolin Around |
||||
| Oscar4u Regular Member Joined: 23/02/2011 Location: New ZealandPosts: 42 |
Good morning Bob you are talking my kind of language I think. I have once in my short life seen a three phase motor used as alternator but the guy who made it is now dead. Three phase motors are easy to get hold of. Is it better to use a newish one or a heavy old one? How many rpm is more suitable? Other then the motor does one need much else? What do you mean by reduction motor? The gearbox on the end maybe. I will be grid feeding as well if I can make it happen. How fast do you anticipate you will need to spin the motor? You talk of a 24 footer at 120 rpm. I thought someting that size would struggle to obtain that speed. Thankyou very much for your help. Best wishes Oscar Oscar4u - for all your rotary cowshed repairs |
||||
| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
[Quote=Oscar4u]I have seen your coroflute blades . . . I read them as being a toy more then a tool. Precisely; admittedly, I build toys. I being the size of Shrek, for some unknown reason like small stuff. All the stuff I build is very small and works accordingly (if at all!). My reasoning is, if someone likes the design and has the ability, they can up-size the project to suit their own needs. My drive is simple; I like to build toys for my grandson. I just finished a practical adaptation for a VAWT. It uses a 100:1 transmission that winds a mainspring. At intervals, the tightly-wound spring lets go against a tiny alternator, which in turn charges a single 12-volt battery. As soon as I move into my new home, I'll be constructing a very small solar collector that uses oil as its working fluid. In this case, size is not so much a factor as the meager volume of oil will top out at around 500* F. My intention is to pass a loop of this hot oil through a vessel containing water and give me an "endless" hot shower. I've done this before on a much grander scale, but the larger this project goes, the more danger it is. My current idea is to make it really tiny so if something pops, it's less of a danger. I'll keep everyone on the 4m in the loop as to my progress on this and other endeavors; I have been on a 6-month hiatus. Edit: Re-reading this reply and seeing I had made mention of my physical size, I thought it best to relieve your fears: NO! THAT IS NOT ME ON THE SCOOTER! 
. . . . . Mac 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 |
||||
| Oscar4u Regular Member Joined: 23/02/2011 Location: New ZealandPosts: 42 |
Hello mac never heard of a solar panel like that. We have two vacume tube ones. Like it very much. If you send me a ticket I would be happy to come and see your setup?? if I build a 6-7m set of blades does coroflute seem like a good idea? Because they are so light they seem a lot safer. If it is made well the chances of the middle pipe falling of shouls be very small. If the coroflute itself fell of it cant be as leathal as wooden blades flying. Thankyou very much Oscar Oscar4u - for all your rotary cowshed repairs |
||||
| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Oscar Have you done a three month wind assessment as the project you are talking about would be a big contract and you need to know it it is viable before you start as it could turn into a big white elephant. I personally like the old motors as they where designed for long life, the new ones are not so much, and they operate at a lot higher temperatures due to modern insulation but seem to fail more in my experience. An old 750 rpm motor would be ideal if you can find one, there are a lot of 1000 rpm motors around also, the new ones are usually 1500 or 3000 requiring more gear step up ratio. According to Alton:- A 6 meter prop would produce 210 rpm at 9 ms and have 5kw energy at that speed. A 8 meter prop would produce 140 rpm at 8 ms and have 5kw energy at that speed. The other option is to use the geo 222 blades Phillm supplies as I have found them to be 30 % more efficient than the profile proposed by Alton. And you could combine them with a compound AXFX self build alternator self build as it then can be used with a lot of existing parts and GTI to save re inventing the wheel. That is the way I have decided to go rather than using synchronous heavy motors. That is if I live long enough to do all the things I want to do. All the best Bob Foolin Around |
||||
| Page 1 of 2 |
|||||
 Print this page |
