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Forum Index : Windmills : The Column 700w-3b-12f VAWT
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| faroun Regular Member  Joined: 18/09/2008 Location: Posts: 62 |
hi there guys, here is my latest turbine created. i have been having a great discussion about it on another great Forum. i figured lets see what you guys think! it is a VAWT turbine that uses airfoil for a vawt blade. created, designed and developed by sam chamas and prototype manufactured by farmenergyinc.ca i am sure there are questions..lets see how it goes. here is the youtube link...enjoy. YOUTUBE LINK regards sam chamas Many Ideas One Brain. http://www.wrapwind.com |
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
faroun That's a clever design. I'm curious why one turbine was spinning and the other was stopped. Does your VAWT self-start or do you have to give it a little push? Does the spinning one have more blades than the stopped one? It'll be interesting to see what it does with a load. I should think widening the blades at the center, to give them more leverage on the axle, which will act as a "moment-arm" against any load, would be an advantage. I'm eagerly awaiting more videos; thanks. . . . . . 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 |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Sam Looks like it has potential but needs to be built a lot stronger with more blade support. Im not sure what the noise is it sounds like the blades moving in the end plates. I built a simular one thirty five years ago it was 2 foot diameter with three blades 8 inch cord, with symmetrical airfoil. I found that if I spiral twisted the blades 8 degrees top to bottom it ran smoother and a lot quieter. It used time expired helicopter blades from the local helio repair shop. The blades where held at four points with clamps with insertion rubber to damp our resonance. I used a small sevouris rotor on the top to make it self starting. All the best Bob Foolin Around |
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| faroun Regular Member Joined: 18/09/2008 Location: Posts: 62 |
they are 2 diffrent turbine layout, it was done like that for testing. the successfull one if the Column-reverse and the other is the Column forward. i do explain alll that in the other videos. it self starts at 13kmh wind. but also i have added a savonius on top for it to start at 8 kmh wind. also i show how i did it in ohter videos. they both have the same blades. regards sam Many Ideas One Brain. http://www.wrapwind.com |
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| faroun Regular Member Joined: 18/09/2008 Location: Posts: 62 |
My custom blade design is tapered and not rectangle shape, the tip is smaller than the base (mid point). The blades are made from solid wood. regards Sam Many Ideas One Brain. http://www.wrapwind.com |
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| faroun Regular Member Joined: 18/09/2008 Location: Posts: 62 |
hi guys, i did some calculations and the result was not so wow.. please review and see if i am correct or not..thanks [size=150]P=½pAV³ P = power in watts p= The air density (1.2kg/m³ @ sea level and 20° C)=1.2 A = The swept area of the turbine blades (m² square meters)=1.7m² V = wind speed ( meters per second) the VAWT is 12' tall wings and a 1.5' diameter arc, the swept area A=18 ft² = 1.7m² Wind speed @ 15 mph = 6.7 m/sec Wind speed @ 30 mph = 13.4 m/sec Wind Power at 15 mph is: P=½(1.2)(1.7)(6.7)³ = 307 watts Wind Power at 30 mph = P=½(1.2)(1.7)(13.4)³= 2454 watts then we introduce the wind and alternator efficiencies factor: of Ct and Ca [size=150]P=½pAV³CtCa you could expect about 40% of 60% of the wind power Wind Power at 15 mph is: P=½(1.2)(1.7)(6.7)³ (.40)(.60)= 74 watts Wind Power at 30 mph = P=½(1.2)(1.7)(13.4)³(.40)(.60)= 589 watts is the above numbers relestic? note: i posted the exact info and request for feed back on other forums, just to see if i am not fooling myself. remember that with this narrow design i loose tork but i gain rpm inertia. thanks sam Many Ideas One Brain. http://www.wrapwind.com |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
I like the design, but the simple fact you could friction brake it with a piece of wood onto a 1" shaft rings some alarm bells, to the behavior of it with a generator attached. It would be nice to know the rpm it reached unloaded, as mills dont reflect a very close relationship of rpm to anemometer wind speed. Watching with interest. Pete. Sometimes it just works |
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| faroun Regular Member Joined: 18/09/2008 Location: Posts: 62 |
pete, it was silly of me to let it spin wild like this, i should balance it first, then connect a gen that i am working on, and then let the sucker go, i am sure it will reach the 500 to 600 rpm but i wonder if it will stay together. i am working on 9coils and 12 magnets axial flux, i want no power drawn form it at 200rpm but bettween 200 and 600rpm is where the power is, and i know that the turbine reaches 200 rpm at 10kmh. So this turbine will not make anypower bellow 10kmh. any thoughts on that?!? regards sam Many Ideas One Brain. http://www.wrapwind.com |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi Sam, I would be doubtful if you will reach that high of rpm with a vawt and the speeds you are quoting are Hawt sort of speeds. You watch the prop on your other mills (hawts) in a good wind and then see if you think the Vawt is keeping up with them, i dont think it would be possible. I think you will need to aim for around half that cutin speed, and then torque could be a problem. It will still be interesting to see what you get out of it. Pete. Sometimes it just works |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Sam It's a neat little windmill. Just going over your calculations and I can see a problem. Your using swept area to work out how much power there is avaiable from the wind, but that only applies for a HAWT with a turbine facing the wind. Its different for a VAWT like yours. Your wind area is 3.657m high by .457m in the middle. But what we dont know is the diameter at top and bottom. Once you know that, you can work out its area thats facing the wind, at a guess somthing like 1.2m2. Pete's right about the lower RPM for a VAWT, but looking at the video I think you have a reasonable RPM, thanks to its small diameter. If you can get it taller you will gain power while keeping the high RPM. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| faroun Regular Member Joined: 18/09/2008 Location: Posts: 62 |
the turbine is top:mid:bottom 15:30:15 inside of ring 20:40:20 outside of ring and the blades are 76" x2 =144" high note that i am tlaking the Column-R is the winner, not the Column-F. regards sam Many Ideas One Brain. http://www.wrapwind.com |
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| faroun Regular Member Joined: 18/09/2008 Location: Posts: 62 |
Also the turbine is 145lbs. made form solid wood. i am not sure how to add the wieght+rpm into the equation. i am sure that there is a diffrence bettween a light and heavy turbine, but not sure where to apply this mass advantage!? any thoughts? thanks sam Many Ideas One Brain. http://www.wrapwind.com |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Sam The rotational mass wont make any difference to the power absorbed from the wind but will give you a bit more inertia, so it will store a little bit of energy like a flywheel and smooth out the gusts a bit. All the best Bob Foolin Around |
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| itsandbits1 Regular Member Joined: 13/08/2010 Location: CanadaPosts: 81 |
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| faroun Regular Member Joined: 18/09/2008 Location: Posts: 62 |
i have slowed things down at this time, in order to show that it can reach high rpm, i have to balance it first, so i am hoping in the next few weeks i will achieve the balancing goal. i am also increasing the the size to top:mid:bottom = 22":42":22" by doing that i will drop the rpm to 500rpm produced at 30mph= 515watts A typical wind turbine efficiency (Ct) is about 40%, and alternator efficiencies (Ca) are about 60% efficient*. These numbers will vary depending on the designs P=½pAV³CtCa p= The air density (1.2kg/m³ @ sea level and 20° C)=1.2 A = The swept area of the turbine blades facing the wind (m² square meters) = 22"+42"=64"/2=32"x144"=4608"=2.97m² facing the wind, that is for the hawt. lets say that my vawt blades most effecient at 50% facing the wind, in this case A=1.485m² V = wind speed ( meters per second)=13.4m/s P=½(1.2)(1.485)(13.4)³(.40)(.60)= 515 watts i will be happy with the results above, because my structure can hold 2 or 3 of these turbine in the same area. regards sam Many Ideas One Brain. http://www.wrapwind.com |
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| faroun Regular Member Joined: 18/09/2008 Location: Posts: 62 |
hi guys, here is where i am at. i increased the diameter of one and adjusted both to be Column R. You tube video regards sam Many Ideas One Brain. http://www.wrapwind.com |
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fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Hi Faroun, Just as a matter of intrest , what airfoil are you using ? PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| faroun Regular Member Joined: 18/09/2008 Location: Posts: 62 |
i am using my own modified airfoil, based on knowledge from my work experience. regards sam Many Ideas One Brain. http://www.wrapwind.com |
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| faroun Regular Member Joined: 18/09/2008 Location: Posts: 62 |
I am very..very disappointed for not able to build it correctly. I feel I am stuck, I cant go forward until I can build the vawt and balance it right. It is disappointing when I tried to avoid all these problems by cutting the disks on the cnc and took my time and measured many times before I put it together. So all I got is the following: 3.2m/s I got 200rpm 4.5m/s I got 320rpm (and as you can see in the video, I did not let it spin to its fullest, but that is all I got for now) All I can say, that based on the bit of info that I have, I can see the turbine making the 500rpm at 6 to 7m/s and that is the only thing that is keeping me happy. For some of you, I think you were waiting for an awesome finish, but sorry to let you down, I need to figure a way to build it right. youtube video regards Many Ideas One Brain. http://www.wrapwind.com |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
faroun Chin up, mate; join the club. That's about 90% of what this is all about. Look at my signature line, "Nothing difficult is ever easy." Those immortal words are from Bullwinkle Moose. To add a little more posture, I quoted Morgan Freeman saying something similar. Your balance problem may very well be something as simple as a variation in the density of the plywood (?) you've used as your center spreader plate. I noticed there are some speeds that seemingly are not affected by imbalance and that's why I think it's something simple like this. Since you show yourself using a "board brake" on the main shaft by leveraging a piece of wood against it as it rotates, I'll assume the existing center circle is attached to the main shaft solidly and if that's the case, it seems to me it wouldn't be much work to cut it out and replace it with three symmetrical-section wing-shaped spars all the same weight. If the problem is in that center circle, doing this would both lighten the build as rid you of the imbalance. Don't worry about losing any "flywheel effect" by lessening the weight. What you gain in momentum, you lose in overcoming it at start-up; it's a wash. The genius of the VAWT is its simplicity and high(er) torque in low-speed winds. If I were building a VAWT (someone slap me!) I'd be shooting for two or three huge paddles in the wind and use a transmission (V-belt most likely) to change the raw torque into speed. For those purists that can't bear to see the word transmission, I'd maybe design a rather large axial-flux rig that would reach cut-in at somewhere around 90 rpm. Everything (well almost everything) is possible. You merely have to take it one item at a time and march on. You're lightyears ahead of most; don't give up the ship just yet. One small change could spell success. . . . . . 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 |
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