 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 : Is a Dar to Sav Morph the answer?
Page 1 of 3   |
|||||
| Author | Message | ||||
| VAWT Newbie  Joined: 13/08/2010 Location: United StatesPosts: 13 |
I posted my idea a couple weeks ago but I have a TON of questions. I'm definately no expert but if I get an idea I play around drawing it up to see what shakes out and below is what shook out. Is having blades that move from a Dar to Sav position really worth anything? I hear only high rpm turbines with high torque are worth anything. 2nd question is what do you call it? cycloturbine, giromill, Dar-Sav Morph, or what???? The idea: In low wind speed the blade tip guide pins run on the innner drag track (lower left). When the wind speeds up the blade tip guide pins will take diverter track A out to become a lift type (lower center). And as the wind slows down they will take diverter track B and move back in. How many blades and what shape might be best for a Dar to Sav blade pitch Morph? Compromise is never a good thing but I realize the blades shape can't morph. 
Does it have potential for on the grid homeowners? Thanks in advance of any advice. |
||||
MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
VAWT Welcome to the 4m. All the ideas are good, but if you're interested in what works, that's where it gets a bit sticky. For starters, any VAWT that produces enough electricity to tie to the grid, will be GINORMOUS! If you live in a very high wind area and have no neighbors for miles, this might be a real possibility. Pretty much everyone on the 4m has tried their hand at the VAWT, be it Savonius or Darius or a "morph" of the two disciplines, but everyone will also likely agree they don't develop much power. The power extractable from the wind is proportional to the cube of the wind speed as well as a function of the "swept area". Vertical windmills have as a rule a very small swept area, even if they are many feet tall and wide. For this reason alone, they somewhat drag their heels in the race for power production. Just take a look at the many commercial wind-energy "farms" around the world. How many use vertical applications? Not many (read that 'none') and there's a reason for that; they don't work well. They're lots of fun to watch and very simple to build (however balancing can cost you most of your hair!) but their place is more in line with "kinetic art" than power production. Peruse the 4m and see what most people are up to, myself included: HAWT There are many times more Intellectual resource here on HAWTs than on VAWTs (even though there is quite a lot on VAWTs). Given a set amount of time and resources, you'll be way ahead trying your hand at HAWTs than anything else. That's my 2-cent's worth. . . . . . . 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 |
||||
Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Well said Mac, Vawts is like riding a donkey in a steeple chase of Hawts. You will always be a looser before the race beguins. Wind generators have been around longer than most of us have, and everything has been tried before. The reason why you dont see designs in use like yours above is they simply dont work well enough. Secondly think of the noise that thing will make with all those moving parts. Have a look on fleabay for lots of useless designs that simply will never make useable power, there is 100s of them. Most here know just how hard it is to make any amount of useable power and is why the Hawt and its overall size is adopted. By all means carry on with your project, but i cant help feeling you are trying to get blood from a stone, and rather than sit and watch you flog a dead horse prefere to tell you so. One thing you have over looked is centrifical force on the blades and the design will become a self braking rotor with rpm, and not behave the way you intend it and increase in speed. Good luck. Pete. Sometimes it just works |
||||
fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi VAWT, I first became intrested in windpower after reading "Windstuffnow" Ed many years back , the thought of the vertical axis does intrest me and I remember Ed had devised a vertical axis which had a cam controlled by a tail to pitch the blades into the direction required , you might want to have a look at that . All I can say is if you want to go with the VAWT idea , have a go , everything is a learning experience. PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
||||
| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Vawt As I have made a number of VAWT in the past with experimental ones like you propose, I would suggest that you keep it simple, the ones I tried with variable angle blades where prone to vibration and excessive noise. The pivot points need to be sealed ball bearings at at least two points on the blade to prevent blade twist and flutter. A good design fixed blade VAWT is the way to go for simplicity and reliability, in saying that the size that is useful isn't really suitable for suburban house lots, as it needs to be at least 20 ft to the lower portion of the blade and 12 foot blade length, this is a large structure. The ones I made where used in rural areas and proved to be reliable and good power generators in open areas with wind speed of more than 8 mph. The smallest one I made was 4 foot diameter 6 foot high, and it would put out 20 amps at 32 volts in a good breeze 12 - 15 mph, it stood 20 foot high so was easy to mount up and install. All the best Bob Foolin Around |
||||
| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
VAWT Given all the variables with wind, I've found the motto, "Simple is best." applies. With that in mind and also given that high-speed vertical VAWT applications are hard to build, erect and control, I should think a fairly-large "drag"-only unit would be the way to approach this using large paddles in the wind and running the power through a transmission (belts or gears) to manipulate the torque. To that end, I once designed (notes on a napkin thing) a large "S" shaped aluminum tube thing made of welded aluminum tubing bent into the shape of the letter S forming a loop with a top "S" and a bottom "S" joined at the ends and mounted about an axle at its center as the "S" laid down. The axis was through the center looking down on the letter S shape and it was to have rip-stop nylon stretched over the poles to act as large scoops. As the wind blew past it, these scoops would pick up the flow (drag) and it would become a large Savonius contraption. My thought was that this could be something like 4 or 5 feet wide and maybe 10 to 15 feet long with the axle mounted at the center of the longer side. The idea was to garner lots of torque and use either v-belts or gears to manipulate the power into something useful. This machine was designed to be placed in an open pasture no higher off the ground than about 6 feet, so the cows didn't get tangled up in it! Something like this might be food for thought if you're going to follow up with a first-build. . . . . . 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 |
||||
| VAWT Newbie Joined: 13/08/2010 Location: United StatesPosts: 13 |
I appreciate all the advice on going to HAWTs but I am a stubborn fool. I think we can all agree that if a windmill will pay for itself in a year or two and keep running for a couple more it is viable. Making it cheap and simple is a must but I am hoping that being a DAR SAV Morph will make it produce power under any wind speeds and you need moving parts to morph. Materials: Rotational molded plastic vane and track plates. 3 pieces for easy break down and shipping. Blades are extruded high density foam (cross linked polyethylene)cut to length with replaceable injection molded wear pins and hinge pins. It has very few parts and NO metal parts. Plastic on plastic makes little to no noise and the foam blades should remove any vibration problems. Size: The blades probably can't be any taller than 6'. Centrifugal force and blade load balance: Light weight foam blades will produce little centrifugal force. The blades are evenly loaded on the hinges because the leading edge is thicker and will not extend outward as far as the thin tapering trailing edge extends inward. The load is balanced but not the surface area, so when it speeds up the blades will want to swing out to the outer track by means of a track A and back to the inner track when the wind slows down. Cost: The rotational molded vane and track plates and the extruded foam blades would be cheap if mass produced. Could be as low as $50 cost to produce. I don't have any electrical back ground and generators and converters look expensive but is there a way to mass produce small ones cheaply. It would be really great if there was a turbine you could buy and mount anywhere and knew it would pay for itself and much more before it broke considering the life is based on number of rotations not age. |
||||
| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
VAWT Build it! The world will beat a path to your doorstep. . . . . . 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 |
||||
| VAWT Newbie Joined: 13/08/2010 Location: United StatesPosts: 13 |
Mac, I wish I knew if you were serious??? Nobody else is giving it any chance. If I could build it I would but I don't want the world beating a path to my doorstep! But it would be something if it helped the world cut back on fossil fuels. I didn't give my design any hope at all until I considered making it small and out of plastic. Actually it was the wife that said make it out of plastic. I laughed but it haunted me and then it all seemed to make sense. She also came up with a name for it "Merry-Go-Wind" and I like that too. Please guys, keep taking shots at my design if I'm crazy shoot me! I hate not knowing if I really have a good idea! If somebody can build half size with 3' tall blades out of wood and provide test data would be really great! |
||||
| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
[Quote=VAWT] . . . if I'm crazy shoot me! Bang! Actually, we're all a bit crazy, but that's what makes life interesting. This is a "DIY" forum. That means you build it yourself and we'll watch with enthusiasm. . . . . . 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 |
||||
| Jarbar Senior Member  Joined: 03/02/2008 Location: AustraliaPosts: 224 |
Hi VAWT,have you seen this http://www.youtube.com/watch?v=vCcHKikC8I4 Anthony. "Creativity is detirmined by the way you hold your tounge".My Father "Your generation will have to correct the problems made by mine".My Grandfather. |
||||
| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Vawt I know what you propose will work and the extra torque will be a bonus, so go for it. The points I made before where from personal experience and I didn't work it to an end product because of the complexity of the mechanisms and the need to static and dynamically balance all the actions happening at once, with your proposed construction method using lightweight materials it will reduce the inertial loading so that's a positive. By the way the generator is the easy part in these designs, so get it working and the rest is easy. Dont forget the stopping brake as you may need it. All the best Bob Foolin Around |
||||
| VAWT Newbie Joined: 13/08/2010 Location: United StatesPosts: 13 |
I would build one if I had the tools but I don't. Maybe a good cabinet maker could build a wood prototype but I don't even know what shape of blades to use for a DAR SAV Morph. I need and aeronautical engineer to do some tough calculations or some computer flow modeling. I don't see the need for a stopping brake it will eventually break on its own! LOL But you could turn the vane manually, messing up the flow, to slow it down enough to grab a blade. The whole idea is to make something that works at any wind speed. I am going to show my electrical ignorance again. Question: Could generator drag be used to regulate turbine rpm? Some kind of variable frequency generator or auto shift drive and a 2 or 3 speed generator. I'd really like a low rpm machine for safety sake and not compromise output. Of course it must be simple (few parts) and very cheap! |
||||
| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
A brake is needed whether it be a mechanical or electrical braking as a wind generator cannot be let run unloaded. The power must be used to apply load to the generator or the mill needs to be braked. It is not always practical to be able to use the power so some form of control is needed. Most smaller manufactured mills use electrical braking by shorting the windings. Low rpm and lots of power would be nice but that is not how things work. You will need to design for 200 to 500 rpm to get usable power output. This is why Vawts are not a very good design. Low speed = low output, or the electrical generator design will need to be large and this is where it gets costly and makes the project not cost effective. You could use gearing but that introduces losses in efficiency, and will effect startup. Wind generators are a juggling act of many factors and each one effects the other. You need to look at all the facts and design around them and with them. This is why i have reservations on your current design presented, as you only have half the picture. Keep researching and adapt as needed. Pete. Sometimes it just works |
||||
| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
VAWT Like I said, "Build something"! Just slap something together so you get a taste of what power there is in the wind. There's nothing like a hands-on project to give you a good slap in the face. It'll be a good wake-up call. If nothing else, go to the dime store (do they even have those any more? I'm telling my age!) and get a "pin wheel" or just make one out of paper (google it). Now, a pin wheel is a HAWT and will be inherently MORE powerful than a VAWT. With that in mind, get it spinning like crazy in whatever wind there is and put your finger against it to see how much "force" is required to stop it. See what I mean? Not a lot of raw power in a little bit of wind even though it "looks" like a lot. Now build a small VAWT out of cardboard and suspend it on a string to act as an axle. You can probably stop its rotation using telekinesis; merely "think" about it slowing to a stop and that'll be enough "force" to do the trick. Once you have a clearer understanding about the true forces at work here, you'll be better equipped to make something happen. . . . . . 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 |
||||
| VAWT Newbie Joined: 13/08/2010 Location: United StatesPosts: 13 |
Now you guys are nicking me with your shots and I am bleeding but I am not dead yet. I am still holding on to the possibility of it paying for itself and more if made of plastic and mass produced. When the blades are in the SAV position one blade will be pretty much perpendicular to the wind and taking the blunt force of the wind. My understanding is that SAVs start producing torque at a lower wind speed then a DAR or a HAWT. I know a DAR or SAV can’t compete with a HAWT on their own. The minimum generator rpm of 200 to 500 is bad news. Maybe thick plastic gears with the smaller one on the generator being a slightly softer plastic "wear" gear and easily and cheaply replaceable. It wouldn't break the budget but I sure don't like the mechanical loss. OK - Here is the BIG question that shows my total ignorance when it comes to electrical. I don’t even know how to state the question or if possible to answer. But can someone show me the math for how much power a 6' bladed VAR and/or SAV could produce per month if placed on typical roof top, light post or telephone pole and how much that power is worth based on a typical electric rate? If it is only $2.00 a month the idea is flat lined but if it is $15.00 maybe there is life! |
||||
| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
[quote]Now you guys are nicking me with your shots and I am bleeding but I am not dead yet. I am still holding on to the possibility of it paying for itself and more if made of plastic and mass produced. [/quote] We are not trying to make you bleed, just want you to see the true facts. So far it would appear you are a arm chair designer and need to do some real experiments like Mac suggested. You ask questions and disregard the answers if they don't support your thinking. It would be best if you built a model of a Vawt (any vawt) and tested things for yourself. It could cost you a lot of money to find out the pit falls otherwise. [quote]But can someone show me the math for how much power a 6' bladed VAR and/or SAV could produce per month if placed on typical roof top, light post or telephone pole [/quote] How long is a ball of string? is what you are asking. Everyones results is different, every location is different, every design is different. I have not seen 1 Vawt built here on the forum that has produced power worth calculating. If there was results we would happily point you in that direction. Pete. Sometimes it just works |
||||
| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Vawt I did some calculations from my earlier experiments and there is good news and bad news, the good news is that I got approx 20 watts per square meter of mill swept frontal area at 4 mph and approx 50 watts at 6 mph with the mill mounted 10 foot above clear ground. The bad news is that you need to do a prototype of your design to see if you can better those results. Looking at your design it could do better, if you can sort out the dynamics of it, but that is only proven by experiment. We are here to support you wherever possible but not to build it for you, as most members are very negative about VAWT, but in saying that there is a few design out there that bare looking at. All the best Bob Foolin Around |
||||
| VAWT Newbie Joined: 13/08/2010 Location: United StatesPosts: 13 |
Yes, I am an arm chair designer and proud of it and work hard to try to solve problems. It takes all types of disciplines working together to get some things done. I know building a prototype is positively essential but when the design is based on rotational molded plastic parts and extruded foam blades it isn't that easy. I have never done any welding or metal work and never done any fine wood working. When I was 8 I made a pinewood derby car in Cub Scouts that barely made it down the track LOL and my only accomplishment as builder was when I was 52 I made the first BulletBobber out of two little pieces of balsa wood that worked. They were too fragile so I had them made out of plastic and now sell them as little side business. If I built my DAR SAV morph out of balsawood it would not hold together long enough to prove anything though it would make Mac and others happier with me. I have listened closely to all the negatives of my design and believe I have conceptually addressed all the problems. The main point that has been made, that I will never dispute is that a HAWT is better at producing power than a VAWT. But there are things such as minimum wind speed, safety, catastrophic failures, noise, permitting, height requirement, avian casualty BS, and return on investment that might be better addressed by a small, low rpm and very economical VAWT. That is why I am on this 4m and again I must say I appreciate the accurate sniper fire and all the help. Telling me to build it is really hopeless. I'm definitely no Einstein (this is a really bad and kind of smart-ass metaphor) but ask you who actually built the A bomb? It wasn't Einstein, he was just another arm chair designer with a much better brain then any of us. I would hate to leave this 4M but does anyone know of a 4m that might be better suited for my precarious predicament as an arm chair designer? I don’t. I apologize for ranting and wish to continue with the economics 101. Am I doing the math right? If it produced an average of 100 watts / hour or .1 KW / hour and the cost of buying electricity is $0.15 / KW hour it will pay back at a rate of $0.015 / hour x 24 hours x 30 days = $10.80 / month? If the numbers did work out like this would you spend $200 for one at Builders Square or Home Depot? This is my whole entire BIG point - Why can't I buy something that will pay for itself and more at a local DIY Home Improvement store or even at Wal-Mart? I wouldn't care if it was a HAWT or VAWT or DAR SAV MORPH made by Little Tykes if it paid for itself and more! If we want to create green jobs, a proven little turbine design could create a lot in short time! There is plenty of motivation behind this idea and I hope it catches on with other designers and builders. Mac is right - Buil it and the world would beat a path to your door or Home Depot. I am just arm chair designer dreamer and don't care much for the filthy rich that don't give back. However I would like to license my design (if a prototype ever gets built and works out) for $0.01 per unit just to keep track of how many were sold without much math. Keep it simple. LOL |
||||
| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
You have taken the armchair designer part to another level, all i ment was to do some actual model reasearch in the field and out of the armchair. For the cost outlay that will give a return and then more, thats safe , can be bought at home depot, the simple answer is buy a solar panel, there is sun every day which is more than you can say for the wind. On an average for any chosen location for the same given cost outlay a solar system will return 4x what a wind generator will, this might have something to do with why home depot dont sell wind generators. If you consider a 4'x 2'x 4" solar panel will return more than your 6' x 6' x 6' monster for less than $200.00 it makes a hard arguement to support. You quote "license my design " do you realise it would not be worth the paper it is written on, as you have displayed your design in a public arena here, so that now makes it common knowledge. As i said before the idea is not new and has been discussed before, even in part on this forum, so to claim it was all your idea first is not quite true, even though you may have thought the design out in your own mind , but others have done it long before yourself. All said i would like to see you build your turbine, but not if it will fail and you loose money, it is why i am negative to some aspects, and not all ideas are good ideas. Pete. Sometimes it just works |
||||
| Page 1 of 3 |
|||||
 Print this page |
