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Forum Index : Windmills : Miller Rotor
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| turnymf Regular Member  Joined: 04/10/2008 Location: AustraliaPosts: 84 |
Not really work clarence, more a fun hobby than anything else I don't know how the miller works and after seeing the little models spin I decided to look further into it The start up rpm acceleration is what really sucked me in What is happening??? I haved tried smaller chord v span ratios yet, only diameters but will soon Origanally I went for 3 tier thinking that it would start without the J shape, just straight vanes Fail I did kick start the single pair of straight vanes but they didn't perform as well as ones with a J shape The miller seems to have two torque spikes So it seems to me that 4 tier may provide more even torque throuhout the rotation Unfotunately this means a 4:1 ratio hieght to width So 60 cm dia means 240 cm height + bearing room at either end This means that I am unable to test the whole thing in the shed as I can only apply wind force to about one pair of vanes So outside it must go I am working on the bracing at the moment I don't beleive that there is any doubt that props(hawts)will out perform vawts in most situations. I have hand held a 50cm pvc 3 blade prop in front of a fan. Only once though as it scared the sh*t out of me I mounted it outside on a small alt and drove some leds Bigish wind came and bent the pvc back so far that the blades hit the pole 11cm behind them and smashed the tips off I took some length off them with a grinder in but it happened again Here at home I don't have much turbulent free wind and the neighbours would have kittens if I stuck up a tower with a prop buzzing around So I play with vawts cheers |
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
[Quote=Clarence] . . . but I intend to go bigger bigger until I get something to produce useful power. I was almost (key word here is "almost") up to making this: I was going to make a three-bladed Savonius rotor out of aluminum tubing bent into partial "S" shapes and mounted on a central axle. Over the tubing, I was going to use rip-stop nylon and make a sail. The upper and lower portions would have tubes sewn into them so the bent aluminum tubes would slide through and be tight. Another piece of aluminum tube with a 90-degree elbow on each end would keep things taught and in shape. Here's the kicker: I was going to make each of the three "blades" 4 feet high and 8 feet long (or visa-versa). The idea was to scoop up lots of torque. 32 square feet x 3 ought to be a good place to start, eh? Maybe you could get away with one that size without your neighbors having a cow. If anybody said anything, you could tell them it's "kinetic art"; a school project for your kid or some other cock-'n-bull story to throw them off the trail! I'm over the VAWT thing, but I eagerly await watching your personal quest! . . . . . 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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| clarence Regular Member Joined: 27/10/2006 Location: Posts: 63 |
Luckily I have no neighbors. miller being sooo easy to construct gave me the vawt bug once again  |
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| turnymf Regular Member Joined: 04/10/2008 Location: AustraliaPosts: 84 |
I have found a little bit of info http://catalogue.nla.gov.au/Search/Home?lookfor=author:%22Mi ller,%20R.%20W.%20R.%20(Roger%20Wallace%20Rayment)%22&iknoww hatimean=1 I have requested a copy Awaiting for the NLA to get back to me Still playing cheers |
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| clarence Regular Member Joined: 27/10/2006 Location: Posts: 63 |
finally got time to wack together a miller. It has 80cm wide 3ply panels [excluding the starting lip] and 120 cm high. the starting lip is 16cm. The space between is 150cm. It is mounted on my neo f&p brake drum conversion I did some time ago. here. http://www.thebackshed.com/windmill/forum1/forum_posts.asp?T ID=899&KW=clarence&PN=0&TPN=5 Today the wind is westerly about 15-25 kmph but very turbulant because of my house. It starts with gusts [no load] and spins for a while but is very hard to evaluate at this time because of the turbulance. It is probably a bit heavy too. each panel weighs about 10kgs. Also I think the panels might be spaced too far apart. Perhaps 120 cm would have been better? Overall I am quite happy with the construction, and it should be strong enough to withstand big winds I hope. Lots of fun  
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Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
clarence, When I look at the picture you have posted I see a pair of- in-congruent blades or optical illusions, It appears that one of your J-hooks is trailing and one is leading ? EDIT: The illusion is resolved, blades are fine. I'm Going to paste a thought here for you guys to mull over. MacGyver, TYMF, Any remarks here? Yea-Nay?? 
Time has proven that I am blind to the Obvious, some of the above may be True? |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Hey, good for you! My hat's off to anything that works. I've been on a downward spiral lately; everything I build just sits motionless. Once all the bugs are out of your Miller rotor, maybe you could post a picture and some final dimensions for we dummies (speaking of self mostly!) out here to merely copy. I still don't see how this thing works even on paper. My son is an aeronautical engineer and he could probably tell me, but won't take the time to even look. He's of the opinion I'm wasting my time on anyything I do out in my shop. For now, I'm still working at manufacturing my own alternator from scratch. Current "quest" is to find some soft iron with low hysteresis (memory -- magnetic in this case). I think I'll try tar-coated tie wire next. I feel like Thomas Edison most of the time. Keep up the good (meaning "successful") work! 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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| turnymf Regular Member Joined: 04/10/2008 Location: AustraliaPosts: 84 |
Clarence I wouldn't worry about the weight too muchat this stage as you will gain inertia, but you might be on the money with the spacing Have you a video of her? I am still waiting for Roger Miller's book, the local library has ordered for me I am still in the shed with mine as I am short of long enough pipe to construct bracing for a stacked config Greenbelt I have tried setting the vanes back as you have in your diagram but it didn't do as well as with them even, I also tried them forward which was worse I also don't see how the chord v span effects it either but it does There has to be something else going on apart from drag downwind and lift upwind, a central vortex perhaps I don't know and thats why it intrigues me so Cheers |
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| clarence Regular Member Joined: 27/10/2006 Location: Posts: 63 |
here is a video. http://www.youtube.com/watch?v=33i0E4lf-SU wind was still from the west approx 30kmph and very turbulant when I made the video. I think it should work better if the wind will ever change direction!!! |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
My son, the aeronautical engineer, says the "camber" of the rotor tip causes lift to the inside. I asked him if it was a drag or lift machine and he said it was both; it lifts as I've already said and drags when the largest surface area is "normal" (whatever that means) to the wind. Well, there you have it; that's what makes it turn. Only problem is, I still don't understand what makes it work. I think I'll be happy merely thinking it's magic and let it go at that! 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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| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
CLARENCE; Link didn,t work Your search - http://www.youtube.com/watch?v=33i0E4lf-SU - did not match any documents. Suggestions: * Make sure all words are spelled correctly. * Try different keywords. * Try more general keywords. * Try fewer keywords. Time has proven that I am blind to the Obvious, some of the above may be True? |
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| clarence Regular Member Joined: 27/10/2006 Location: Posts: 63 |
tried it just then Greenbelt and it seems to work for me.[copied and pasted directly into address bar] Not sure whats going on. |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Try this, as a link. http://www.youtube.com/watch?v=33i0E4lf-SU Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| turnymf Regular Member Joined: 04/10/2008 Location: AustraliaPosts: 84 |
Works here How tall is that tower you've got there Clarence? Is the f&p loaded ? Go bigger vanes instead of reducing the space, your frame looks ready now cheers |
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| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
MacGyver; Lift and normal air; Wind blowing against a flat board is normal air, DRAG. air moving over a rounded form in a smooth angular transition (curve)will normally speed up, Higher velocity causes the pressure to drop, when this happens the pressure on the Flat side of the rounded form will be higher tending to move the object toward the lower pressure. LIFT. This is a very basic Drawing to illustrate the principle,and you will not likely find an airfoil like this. 
Time has proven that I am blind to the Obvious, some of the above may be True? |
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| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
Gizmo, The Hotlink worked fine Thanks. Time has proven that I am blind to the Obvious, some of the above may be True? |
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| clarence Regular Member Joined: 27/10/2006 Location: Posts: 63 |
the tower is about 5 metres and the alt has no load at all at the moment. My house being in the way of the predominately west winds I get here is very frustrating.  My various mills I have tried can spin like crazy and then stop suddenly . I could move my house, but then I would have nowhere to live  .I was thinking what you said turnymf, make larger panels, but I will wait until some south winds come first to see how it works.
Keep those miller theories coming, I still cant get my head around it. update, the west wind is 40kmph now and I timed the miller at 80 rpm at one stage. quite noisy though, woosh woosh every revolution. I think its the starter lip making the noise. It really should be rounded I suspect. Also I wouldn't be making millers with the dimentions I have used, they are probably far from optimal. |
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| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
ALL YOU MILLER GUYS; The Drawing I posted on Page 4 Has Several Flaws, one of which is the direction of travel, next the J-hooks are on the wrong end of the blade. 
I set up a fan in the shed today and cobbled a couple blades from 1/4" plywood and a 2 foot by 6" by 3/4" board. I mounted the blades as shown on page 4 turned on the air Fan and it--- ran backward? There you have It, Murphy lives at my house. I mounted the blades on my cross board using a single screw to hold them on. I could change the angle of attack and then determine the best torque angle for the blades. When taken from the diameter line at the perimeter my best angle was 60 Deg.If I decide to finish this I will opt for a 4 blade design because 120 deg of this circle has no torque. (60 deg. 2 places) 
Time has proven that I am blind to the Obvious, some of the above may be True? |
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| turnymf Regular Member Joined: 04/10/2008 Location: AustraliaPosts: 84 |
Greenbelt, here's something I saw a while ago along those lines http://www.youtube.com/watch?v=iuSO2YA_QT0 |
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| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
turnymf, That looks like a nice machine and working well. Time has proven that I am blind to the Obvious, some of the above may be True? |
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