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frank133
Newbie

Joined: 11/09/2008
Location: Great Britain
Posts: 32

Posted: 02:16pm 11 Sep 2008

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Hi,I am having a slight problem making a set of blades,
I have made some blades out of pvc pipe,[I copied the design of Layne Ericson on u tube].I made them a bit smaller,19inches long, 4" at the base and 2" at the tip,
The first one I tried was two bladed,that was a bit slow.So then made a three bladed one,that wouldn't even turn,[I don't know if I had the blades on right,]
So now I have made one with four blades.It is not fantastic,so maybe I need a wider base and a smaller tip on the blade.
I have a 12v dc dynamo that I am thinking of using,I have to check the output of that later.
I did not realise how much was involved in making a wind turbine.this site has been educational and interesting.
My son can make the dc controller and sort out the electrical side{he works in a university on prototype jet turbines]
I will now sand down these blades,balance them and start making the mounts for the dynamo,
back to the garden shed for me.

CraziestOzzy

Senior Member

Joined: 11/07/2008
Location: Australia
Posts: 135

Posted: 04:12am 12 Sep 2008

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...a good idea for testing your attached blades in the shed is to use one of those portable fans, turn it on "high" and direct the air onto your turbine blade setup...then adjust the angle etc of your blades from there.

http://cr4.globalspec.com/member?u=25757

http://www.instructables.com/member/OzzyRoo/

WooferHound

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Joined: 05/06/2007
Location: United States
Posts: 3

Posted: 04:14am 12 Sep 2008

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Less blades turn faster than more blades
Shorter blades turn faster than longer blades
so 2 short blades will turn the fastest

W o o f -={(
The wind in Alabama doesn't Blow , it Sucks . . .

frank133
Newbie

Joined: 11/09/2008
Location: Great Britain
Posts: 32

Posted: 11:11am 12 Sep 2008

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Thanks guys,very helpful,I was going to use my compressor to blow wind ,but a fan makes a lot more sense.
Not having a lot of luck with the four blades, so I am going to make three new ones,and alter the shape a bit.
I thought the more blades the faster the spin, I was wrong.so I presume the more blades are for more power,
I will now go and make another set,I will go for three blades,[again]
Sorry for asking the dumb questions and thanks for your reply.

frank133
Newbie

Joined: 11/09/2008
Location: Great Britain
Posts: 32

Posted: 07:32pm 12 Sep 2008

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Well guys I just finished making another set of blades,
I cheated a bit and bought pvc guttering,
to saved cutting the pipe down the middle,
I made three blades all the same,20" long 6" root and 2" tip,bolted them up and,nothing,
I tried a fan to turn them [I need a bigger fan]
Then I tried a airline from my compressor,still no good.
I am bolting the blades to the hub along the straight edge of the blade,is this correct?It looks like the wind is trying to turn the blades but also stopping them from turning as well, if this makes sense.
I even tried one blade on back to front,didnt help.
I have googeld myself silly, looking at pvc blades.
I think the answer is simple,but not to me

oztules

Guru

Joined: 26/07/2007
Location: Australia
Posts: 1686

Posted: 09:16pm 12 Sep 2008

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I think it is time you perhaps use these blades on a bearing only.... no dynamo..... in fact you could use one of your alternators for this purpose as they have very little turning resistance compared to the dynamo.(just to test the blades rather than generate any power at this stage) This will give you detail on how they perform.
If they spin up well without the load of the dynamo, but stall/don't turn with the dynamo.... then your dynamo needs grossly larger blades to turn it. It may be that larger slower blades will turn it, but not fast enough to provide the voltage you need....and it is at this point you will be able to decide if this dynamo is not for this project.

If they spin up well on the alternator, try less brush pressure on the commutator of the dynamo and see if that helps it to break away.

For small blades like that a dual axial ironless design will be best suited, as it requires almost no start up torque.... which little blades are awful at providing, or a much smaller motor to drive... tape drive, stepper etc., althoug some torque will still be required for these types as well, but not as much as your car dynamo.

Stick at it Frank, the harder it is, the bigger the reward when it works.

..........oztulesEdited by oztules 2008-09-14

Village idiot...or... just another hack out of his depth

frank133
Newbie

Joined: 11/09/2008
Location: Great Britain
Posts: 32

Posted: 08:25am 13 Sep 2008

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Thanks for he reply oztules,
I understand what you mean,some of my previous projects have resulted in a a dead end at first.

My last adventure was to convert my car to lpg,the conversion itself was fairly straight forward.
But being me I wanted the lpg filler mounted behind my rear registration plate.
I then mounted a electric sun roof motor in the trunk,and cabled it to the reg plate.
I then had a sticker made up,which says HAVE A NICE DAY.
and stuck it behind the plate.at the flick of a switch my rear reg plate folds down,much to the amusement of the following driver,press the switch and it returns back to normal,I incorporated a warning light to show me the plate was down, I wouldnt like to drive past a police car with,have a nice day on the rear of my car.
The police in the UK dont have a sense of humour,
I am off now to have a quick google on pvc blades,
sorry for going off topic,cheers frank.

Marcus20VT
Regular Member

Joined: 02/09/2008
Location: Wales
Posts: 49

Posted: 05:04pm 13 Sep 2008

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I then mounted a electric sun roof motor in the trunk,and cabled it to the reg plate.
I then had a sticker made up,which says HAVE A NICE DAY.
and stuck it behind the plate.at the flick of a switch my rear reg plate folds down,much to the amusement of the following driver,press the switch and it returns back to normal,I incorporated a warning light to show me the plate was down, I wouldnt like to drive past a police car with,have a nice day on the rear of my car.

Fantastic stuff frank!!
Let me know how you do with the blades, as my motor should be arriving soon and I'll need to be making my own blades too!

PS You're right about the sense of humour on the establishment - Its even worse this side with Brunstrum's army of ticket mad puppetts!

frank133
Newbie

Joined: 11/09/2008
Location: Great Britain
Posts: 32

Posted: 08:09pm 13 Sep 2008

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Hi Marcus,
I think I would be the last person on the planet,to give advise on blade design

I am surrounded with pvc blades,I have made a 2 a 3 a 4 blade design I just cant get them to spin,
and in desperation bolted six to a car fan,[which works the best.
I would prefer a three bladed design [because I think it looks better,I think I get the leading edge wrong on one of the blades,
Until I get a good set of blades working I am a bit stuck,
I have made a tail out of sheet metal,but that is putting the cart before the horse so to speak.
I will be the first to admit I know nothing about wind power,only what I have googled,
I will probably have another go at making a three bladed prop tomorrow,

[cant wait to start winding motors]I am going to look around the site at some of the old posts,catch you soon frank

Marcus20VT
Regular Member

Joined: 02/09/2008
Location: Wales
Posts: 49

Posted: 10:29am 14 Sep 2008

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Frank - take a look at this http://www.windstuffnow.com/main/blade_design.htm
if your good with wood, this looks like the way to go.
I suppose you could use nylon as well.

frank133
Newbie

Joined: 11/09/2008
Location: Great Britain
Posts: 32

Posted: 11:35am 14 Sep 2008

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Marcus20VT said Frank - take a look at this http://www.windstuffnow.com/main/blade_design.htm
if your good with wood, this looks like the way to go.
I suppose you could use nylon as well.

Hi Marcus I have come across that design before,
Wood is not my strong point,

If the pvc wont work,i might go for metal blades.
I can get some sheet steel rolled,and go from there.
I am going to have another try today.I am knee deep in pvc blades,at the moment.
This six bladed one I have made works the best,but looks a little crazy.when I find out how to post a photo I will post one.[I dont mind being laughed at]

oztules

Guru

Joined: 26/07/2007
Location: Australia
Posts: 1686

Posted: 09:22pm 15 Sep 2008

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Frank,
In the post reply box, there is an icon (under the word colour). The icon is a pic of a tree with a blue arrow.

Save your photo to your desktop perhaps so it is easy to find. Press the icon(tree with blue arrow pointing up), and use the browse button to find your pic file on your desktop.
Select it and acknowlegde the "be patient bit..." and the pic will be inserted as a string of gobbledegook at the bottom of your edit window.... preview the post and check it is where you want it. If not, you can cut and paste the weird stuff string to a different part of the screed... and preview again.

When all is well, post it. Then we may be able to help some more... or at least cogitate over it.

..........oztules

Village idiot...or... just another hack out of his depth

frank133
Newbie

Joined: 11/09/2008
Location: Great Britain
Posts: 32

Posted: 09:37pm 15 Sep 2008

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Oztules thanks once again mate,
I will give that a try tomorrow

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