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Forum Index : Windmills : Feasible Windmill Plan?
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| floodrod Regular Member  Joined: 08/07/2009 Location: Posts: 70 |
Hi. I been reading the forum and decided I wanted to make my own windmill. SO I got my F&P motor from Randy and am planning my build. I need a Vawt design that is capable of catching good wind but also has a light-weight (but sturdy) mounting system. Something I can mount to a guy wire pole. And to add to the demand list, I would also prefer a top and bottom support for reliability. Here is the plan I came up with 
The idea is that the SAV would start the spin and the giromill would catch the cycle. This would allow me to build it in stages (the sav first to make sure it's perfect, then the Giromill top add-on). Also, it will allow me to mount it right on a guy wire mast. I have a question and would love feedback on the idea. 1. Assuming I use 1" steel tube axle, whats the best way to secure it to the F&P 25mm shaft? I would like it to be detachable for maintenance. (The shaft currently has female threads) Thanks |
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Greenbelt Guru  Joined: 11/01/2009 Location: United StatesPosts: 566 |
Hi Floodrod ; Welcome, I'm curious about the method you will use to match the wind speed to the different radius of the Savonius and the Darrieus blades. Perhaps a different pitch to the blades?. Also, I believe the Darrieus blades should be centered on the support arm. Centrifugal force will likely bend the support rods in high wind. Don't be upset by this negative comment, the Idea looks Promising. Will be Interesting to see the final results. Cheers. Time has proven that I am blind to the Obvious, some of the above may be True? |
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| Rubes Newbie  Joined: 01/05/2009 Location: Posts: 36 |
Hi Floodrod I have just built a vawt with a f&p genny see thread here and here which is currently an impressive looking garden ornament, I believe that you would have to build a fairly big machine to drive the f&p, while my attempt has been a rewarding learning experience in retrospect I should have started with a hawt (which is my next project, much to my neighbours delight). Don't let me put you off but with the same material costs you could have a mill that puts out much more power. As Geenbelt says, the blades on your design need to be supported a bit more as they are subjected to enormous forces when they approach anything like the speed needed to generate usefull power. |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5119 |
Yeah I agree. Your first serious windmill should be a conventional 3 blade HAWT. They are easier to make, and they work, simple as that. VAWT's do look cool, and can be made to work, but usually lead to dissapointment. The only VAWT I built that was close to making any usefull power was a Lenz2, and even at 1.3 meters wide and 1.2 meters high, it was too small to give anywhere near the power of my trusty old HAWT windmill. The problem with a VAWT is making them big. The Lenz2 could capture 1.5m2 of wind, while the HAWT with its 2.2 meter diameter was capturing 3.8m2 of wind, and therefore much more power. HAWTs are just easier to make bigger. But if you dont mind experimenting, and are prepared for a machine that might not work, then go for it, you will learn as you go and it will be fun trying. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| floodrod Regular Member Joined: 08/07/2009 Location: Posts: 70 |
Right Right and Right.. I would rather build a Hawt but not this round. I have an acre of land in a community, but I'd need a 35'(ft) tower to clear the trees. I don't think I can push that far without stirring up trouble. But I do live in a 3-4 wind zone area and can get a nice size vawt up higher than the house roof. (not on the roof) When the leaves fall and winter rolls in, our windows rattle from the wind. The Giromill add-on was not thought all the way through. I will hold off on anything fancy for now and start with a 4ft X 4ft sav on a top and bottom braced axle. If this isn't powerful enough to drive the F&P, I can always drive a smaller generator with it. (assuming I live up to my challenge). So, I picked up the steel frame tubing, 6ft threaded spindle rod, and lots of bolts and such. And I just ordered the 2 main support bearings to fit the axle rod. Now to brush up on my welding skills as I wait for the bearings. I appreciate the feedback on the Vawt/Hawt, and I agree, but I want to avoid the town and community permit process. When I do manage to move to large acreage, I will definitely do the hawt. If you guys don't mind, I would like to keep this thread updated by posting pics and steps of my project. I like being on the chopping block  |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
Best wishes for your project and regarding fears that the F&P may be too big for your VAWT I recall Backshedders have in the past experimented with moving the rotor 'out of mesh' somewhat to reduce the load on the turbine. My own experience when an F&P proved too 'big' for my purposes I solved by cutting away a large part of the stator. John |
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| floodrod Regular Member Joined: 08/07/2009 Location: Posts: 70 |
For reasons stated above, this is the new design plan. 
A lot simpler and expandable. I'll make sure I configure it with a removable axle for tinkering. |
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MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
The VAWT designs are all "drag" machines. That means the vanes are at a constant stall and just swim in the current similar to a paddle wheel in a flowing stream of water. A HAWT is able to utilize lift and drag as well as apparent motion to increase the amount of power tapped from the moving stream of air. I've built both and the closest thing I've see so far to a good working model uses a semi-helical design that is used to take advantage of 'rising' air currents. Again, this is merely an 'air screw' mounted vertically. If viewed from a point parallel to the axis, it's merely a propeller; same as a HAWT, but it's mounted on a vertical access so it fools us into believing it's something other than what it is. If you can design the blades on your VAWT to be large scoops that grab a huge amount of air each swirl, you can utilize standard mechanical transmission methods to increase your shaft output speeds. Ideally, a VAWT should be a slow-moving, very-powerful design. If you try to make it spin fast, controlling it is a nightmare; it'll get away from you before you know it. Hope this helps. I'm not saying don't build a VAWT. Do, they're cool; just be aware of the limitations. 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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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Floodrod, I hope your neat drawing above is only conceptional and not really what you are trying to build. If you do, you will get the same disappointment than I did with a one side only bearing support frame on a VAWT. IT IS NOT STIFF ENOUGH. You do need the frame continuing right across to the other side and have a vertical brace on *both* sides of the vane blades. Like having the blades inside a box [] instead inside a '['. Klaus |
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| floodrod Regular Member Joined: 08/07/2009 Location: Posts: 70 |
Thanks Macgyver. Good input for me to ponder on. Since the winds in my ideal mounting spot will be a bit too turbulent for a hawt, I will have to do the best I can with a vawt. So I will investigate the idea of incorporating "lift" as you suggest. So I will start with the frame as I digest more information. Tinker- I can see it being wobbly if the mounting pole was directly under the generator. This would make it way off center and very hard on the mount attachment point. I was thinking of a mount more along the lines of the pic below 
I could even attach the top and bottom bearing brace arms to the mounting pole for extra strength. This is going to be a strong and proper built frame which will be bolted and welded at all joints with good size steel. If needed, I can weld some 90 degree triangle supports in the inner corners (at the sacrifice of wing-room). I suppose it's going to rely on the inner 90 degree joint stregnths. But you may be right. The whole C clamp idea may result in failure. |
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| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
Floodrod; Take a look IDEAS??. Time has proven that I am blind to the Obvious, some of the above may be True? |
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| Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Your last drawing is almost exactly like my last frame looked - it did NOT work! It was fine for low wind speeds but as soon as a gust hit the horizontal arms moved ever so slightly out of alignment to each other, resulting in a horrible shaking of the whole contraption. I had used 75x25x1.6mm RHS (rectangular hollow section) for the frame. I am about to complete my [] frame modification but its too stormy here now to test it, maybe next month. Klaus |
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| floodrod Regular Member Joined: 08/07/2009 Location: Posts: 70 |
Tinker, I'd love to see a pic of the old design and perhaps even the broken version of it. If you have them, it will be very useful for evaluation |
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JimBo911 Senior Member  Joined: 26/03/2009 Location: United StatesPosts: 262 |
I belong to the Illinois Solar Energy Association and attended one of the member meetings which involved going up to the roof of a building in Chicago to witness this vawt in action. Hopefully this may help with some ideas. http://www.aerotecture.com/products_610V.html Jim |
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| floodrod Regular Member Joined: 08/07/2009 Location: Posts: 70 |
Thanks for the suggestions guys, but I will take the advice given and go for the Hawt as the GURU's suggest. I might not be able to get it up past the tree line, but I really don't want to waste the F&P motor.. I have recently got my hands on another motor and I may come back to the Vawt with at a later time. I will post pics as I progress:) |
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SparWeb Senior Member Joined: 17/04/2008 Location: CanadaPosts: 196 |
I missed the beginning - you've gone a bit far with a difficult design. Try a clutch bearing. A google search will lead you to Timken or Torrington Bearings. The bearing fits over a shaft and rolls only one way. The sav grabs the darrieus shaft when it starts to turn, once the darrieus gets going it will turn faster, the savonius doesn't slow it down. Steven T. Fahey |
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GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
The one way clutch-bearig is a sprague clutch. You should use them with the correct hardened inner race. The clutches do have friction, more than a ball race. I measured around 10W@800RPM for a 25mm dia x 25mm long clutch in the free wheel mode, that I used in a 2 speed gearbox I made for my Solar Racing car. Gordon. become more energy aware |
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| floodrod Regular Member Joined: 08/07/2009 Location: Posts: 70 |
Okay, so here goes my first build.. Keep in mind that I have had my welder for about a week now and never welded before. With this said, I tried getting away with as least welding as possible but I did manage to blob up the joints with weld and the thing is solid. Picture 1. After going to the local hardware stores many times, I managed to piece together a framing idea. The basic idea is something like this picture. 
I used a thick steel computer chair support. 90 degree (actually a bit under 90 degrees). I measured this plate to be a little more than 1/4" thick. One end supports the front bearing, and the other end will weld to square steel welding metal. Two stainless 1/2" threaded rods will be used to clamp the F&P bearing in place. 3/4" steel pipe will then connect to the square weld metal to complete the tail. 
The whole thing should look like this: (without the Clutch Plate) 
Off to the welding room.. 
As you notice, I am horrible at welding. Everyone's gotta learn. 
Welded it all in place and slapped on some green Rustoleum. 
The mount is 2 FT of 1" Steel pipe threaded and welded which slides into a 1 5/8 inch steel mast. The ya bearing setup swivels around easily and smoothly. The tail is 3/4 steel pipe with a 45 degree elbow and some 3/4" round weld steel fits right in to it like they were made for each other. I am not totally sure on the furling part, but it looks like it will furl with the swinging tail. 
All pipe/metal connections were glop welded as best as I could and reinforced with bolts and lock washers. I put most my weight on the tail base and there was no sign of weakness. I am thinking of drilling the middle of the base so I can feed the wires into the mounting pipe. Not sure yet. Need more info still. I do have a question though. With the furling, should I install some sort of stopper on it? Should it furl all the way around, or furl till it hits a stopper. It seems to me that a stopper is necessary? Suggestions and feedback welcome. |
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| floodrod Regular Member Joined: 08/07/2009 Location: Posts: 70 |
Looks like I found one answer when scrolling through Gizmo's pics for the 100th time. It looks like there is a stopper on the furling. 
And another question regarding the nut where the arrow is. When I tighten that nut up the shaft seems to stiffen up and spinning is harder. If I leave it loose, it spins great. Should this nut be wrench tightened against the bearing? If so, could I put a washer there to perhaps divert pressure from the bearing? |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
If the bearing becomes tight, when the nut is tightened, then you may need to shim, between the bearing and the internal spacer on the shaft. The shim thickness will need to be adjusted for the minimum shaft turning torque that still holds the bearings in place. Gordon. become more energy aware |
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