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MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329
Posted: 03:30am 02 Jul 2011
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[Quote=Mac46] . . . the wind changed direction and the show was over.
I'm just curious why a change in wind direction would matter, since this is a VAWT. I suppose if the wind were to come from a direction that was 'shielded' by the terrain or by trees that might be a reason.
Just curious.
. . . . . 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
mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412
Posted: 01:25am 03 Jul 2011
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Hello Mac,
You are correct...I have 2 very large Maple trees directly SE of the mill approx. 125 feet away. When the wind is from this direction the mill is in a dead zone. Most of my wind comes from the SW, W, NW, and N directions...except when a warm front is pushing in from the South. I won't have this trouble as much during the winter mounths since the leaves will be off the trees.
No further progress to report, very busy with other things.
...Mac46I'm just a farmer
smithy Regular Member Joined: 30/01/2011 Location: AustraliaPosts: 52
Posted: 11:00am 03 Jul 2011
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VAWT;s aren't immune from bad wind, I have houses around me and the direction I have a street gives me clean wind which allows the VAWT to hook along. Wind direction over the neighbours houses is like a wind shadow. It even occurs when the wind is coming over the roof line and in the shadow of the tilted solar panels.
Difference between VAWT's (lack of noise)and HAWT's is firstly the noise but also that they don't go seeking the wind with changes in wind direction.
Other than that they still suffer in wind shadows.
As people keep telling me, get it up higher.... and higher!
Smithy"The answer my friend is blowing in the wind, the answer is blowing in the wind" Bob Dylan
mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412
Posted: 01:23am 04 Jul 2011
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Hello smithy,
Yes you'r very correct about wind shadows effecting vawts as well as hawts. A steady direct line wind is something to be thankful for. Thanks for posting and its good to see that you'r still following the thread.
...Mac46I'm just a farmer
mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412
Posted: 11:09am 09 Jul 2011
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Everyone,
Just to busy to do anything more with the mill lately, sorry. I have had a few new guests stop by to look and touch it, ect. They are impressed...even with the break set and the mill just sitting there.
I have plans for a electric starter motor to spin it up, but like I said...just to busy lately with other things.
...Mac46I'm just a farmer
Air Bender Senior Member Joined: 25/01/2011 Location: AustraliaPosts: 206
Posted: 01:17pm 09 Jul 2011
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Hi Mac46
I saw on the net the other day that there is a bit of a craze going on building micro windmills out of CDs. One i saw was a set up where the CD folded out by the force of the wind and pushed the mill around by drag and then folded in flat as it went around into the wind. I thought this would work well on a lift mill. As they would fold in flat and not cause drag when lift started to kick in.
All the best Dean.
mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412
Posted: 11:46pm 09 Jul 2011
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Air Bender,
Hello Dean,
I think you have a good idea there, but I have a feeling that I'm at my max weight limit as it is now. Adding anything more will be a problem, thats why I am looking into a motor to spin it up to speed...won't add any additional weight to the rotating assembly. I'll try this and see what developes. (if I ever get time).
Thanks for posting the idea.
...Mac46I'm just a farmer
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 02:35pm 10 Jul 2011
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Dean, I see similar contraptions fitted to the cabin tops of moored boats to scare the seagulls off them .
I think the constant 'klick, klack' as it turns around would drive you mad in no time Klaus
mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412
Posted: 09:31pm 10 Jul 2011
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Hello Tinker,
I was being as polite as I could with my response to the last suggestion, I don't discourage "ideas" or 'Suggestions" but this time I must agree with you, the "Klacking" would be a problem for me.
I have more pressing problems right now...deer are walking up the rows eating just emerged soybeans, and in another field, wild turkeys are walking up the rows scratching up freshly planted soybean seed. Nothing to be done about it, they'r both out of season. "Just wait till season opens".
...Mac46I'm just a farmer
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 01:46am 11 Jul 2011
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Hi mac
My friend has a similar problem with birds and wallabies here in Australia, he has bought himself a radio controlled helicopter and buzzes the paddock to frighten them it works alright and good fun too, He has a high frequency audio thing on it and flashing led lights so he can see it at night. He has another one made out of Styrofoam shaped like an eagle and it hunts the birds very effective as soon as they see it they are gone.
Wildlife is nice to have around and is smarter than politicians but can be a nuisance at times.
All the best
BobFoolin Around
mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412
Posted: 01:58am 11 Jul 2011
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VK4AYQ,
Hello Bob,
I'm a nature spoof and would rather take a picture rather than squeeze a trigger. I figgure that its mother natures way of letting me know that the land belongs to her and all her children. Just don't let me see those deer and turkeys doing donuts with 3 wheelers out there. Thats when I draw the line.
...Mac46 I'm just a farmer
Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301
Posted: 04:24pm 11 Jul 2011
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Hi Mac46,
Seeing as you are fattening them up,what's venison and turkey worth pound for pound over there?Or can it become part of the family menu?Some Aussies are partial to eating the national emblem(kangaroo)Venison and turkey,You Bet!Cheers Rastussee Rastus graduate advise generously
Air Bender Senior Member Joined: 25/01/2011 Location: AustraliaPosts: 206
Posted: 10:03am 12 Jul 2011
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Hi Mac46
I think a starter motor would be cool, just push a buton and of it goes.
My problem is that when i start working on the windmill all of a sudden something on the car needs to be fixed.
All the best Dean.
mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412
Posted: 01:30pm 12 Jul 2011
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Hello Rastus + Air Bender,
Generally speaking I don't follow the price of venison/wild turkey ect; but I do feed a small herd of deer and a few diffrent groups of turkeys among various animals each year by allowing them to range undisturbed.
Working on cars/pickups/trucks/tractors/machinery, ect.ect. house and out buildings, all require a certain amount of attention from us to keep things in order. Then there is the weather, personally, I always complain about the weather, its seems to be always changeing my well thought out plans.
Kind regards...Mac46I'm just a farmer
MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329
Posted: 02:48am 14 Jul 2011
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Mac46
I sorta touched on this a while back and the thought just crept back into my head that if you wanted to make a really robust and H U G E blade, why not build an endoskeleton out of metal, balance that much and then build a mold around it in the shape of the wing section you want and stuff it all with expanding foam?
That foam gets hard like a rock, but is very lightweight and strong, so as long as everything was pretty much in balance, the sky would be the limit as far as size goes. If you pivoted the blades at their root and tip, you could adjust their individual angle of attack and if you wanted to do an extra "spoiler" wing on the trailing edge of each, it would be no big thing to add it with some spruce ribs and a little CA glue.
What ya think?
. . . . . . MacNothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas
Mac, I think your brain is "beetling and spinning away" all the time on windmills.
Did you mean exoskeleton? Excuse my anatomical ignorance but isn't an endoskeleton just a skeleton?
For the engineers and designers, would you find centrifugal forces bending a HUGE wing out in the centre or do the forces support it in the wind at velocity?
Keep up the exciting quest Mac.There must be a way to use the free power blowing past my house
in my house
to stop blowing money away out of my house.
Air Bender Senior Member Joined: 25/01/2011 Location: AustraliaPosts: 206
Posted: 10:03am 14 Jul 2011
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Hi idwatt
I found that the centrifical forces on the wings start to overtake the wind velocity forces once the mill gets to around 100 RPMs, but this will probable very on different designs as some will need more or less wind velosity to reach X RPMs.
So yes centrifical forces will easly overtake wind velosity forces on the wing.
All the best Dean.
mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412
Posted: 12:39pm 14 Jul 2011
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MacGyver,idwatt,Air Bender,
Seems like I remember someone cutting wings out of riggid foam with a "hot wire" but lost track of the thread and so don't know how it turned out. As far as size vrs weight goes...the wings I built are about as light as can be expected, and comparable to the weight/strength ration to std. aircraft wings...even lighter. the limiting factor for "my" windmill is my "center shaft and rotor assembley", not the wings. The rotor will fail long before the wings.
I must agree with idwatt and Air Bender with their conclusions. About the only thing lighter than foam is air...and thats whats inside of my wings. Centrifical force will bend the wing along its span, just like loading a beam layed in the horizontal position...reguardless of any lifting forces created by the wing. These tend to be in a different direction and in the case of the vawt mills the loading and unloading as the wing spins in and out of the wind could creat a problem with flexing back and forth.
Mac, I know it sounds like I'm beating you up here but "no I'm not", just letting you know that its my rotor not the wings that is the weak link here. You'r ideas have lots of potiential...not sure how much all that foam would cost though.
Kind reguards to everyone...Mac46I'm just a farmer
MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329
Posted: 08:15pm 14 Jul 2011
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Crew
This is what happens when an old fart sits in his kitchen sipping hot chocolate, typing on the Internet. Suffice to say, when I said "endoskeleton" I meant to emphasize the fact that it was INSIDE (like the regular mamal kind) but I wanted to make it more clear, that's all. If it were an exo-skeleton (outside) it would interfere with air flow, right?
Anyway, as for the cost of the foam, a can of the stuff, which makes about 2 cubic feet is around $3 at the bix box stores.
Air Bender's comment must surely be why I don't build VAWTs; I knew there was a good reason.
. . . . . MacNothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas
mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412
Posted: 01:59am 15 Jul 2011
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MacGyver,
Hello Mac, Thanks for following the thread and you'r ideas are sound ones.
To be honest, I had'nt a slightest idea of the cost of the foam...much less than I had thought. A person might just be able to make a wing such as you discribe...if it becomes as ridgig as you say, then several structual members could be reduced in size and strength. I have had only one experiance with the stuff...We had a barge on the mississippi river that had a serious problem with a rusted out bottom, Had a company come in and fill the lower hold completly full of the stuff. It sank 2 yearsd later...seems the foam soaks up water. My suppervisor stayed on the deck until it was completely under water, We were busy shutting down the 3-phase 480 volt power lines feeding the pumps. No I did'nt get any pictures, sorry. Yes, my suppervisor did know how to swim, he survived unharmed.
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.
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