My plans for a new windmill. Success or failure?

[Sponge]

Hi,

My first windmill wasn't really a success. Made of harddisk magnets and copperwire from an old vacuuum cleaner engine, it just didn't make more than a few volts.

(http://www.persistentrealities.com/windmill for a LOT of photos)

Last weekend I took apart this old HP Deskjet 520 printer, and found this 12v "stepper like" motor, to move the paper or printerhead. It isn't a real stepper engine (two wires) but it does have some steps. It doesn't take that much of effort (I think) to turn the motor around, and it produces 12v pretty easy.

After visiting this site again, and seeing the water genny, It made me a bit more enthousiastic again . Since magnets are me a bit too expensive for this experiment, I'm going to try this 12v motor.

Unfortunatly I absolutely do not have the tools to make a decent airfoil shaped blades, No electrical "standing up" saw, no drawing knife (looks wonderfull to make blades with), just a saw, "normal" electric saw, and sanding paper.

So this time, I think I'm going for a very simplistic design (no airfoil), not sure if it will perform well, but it can be made in a few hours I think .

What do you guys think?

[Dan M]

Neat woodgrain surface on the 3d modeler.  Without any twist you will probably be disappointed in the results.

If your blades aren't too long, you might want to consider foam.  I bought a hot knife for 4 or 5 bucks at a DIY store a few years back.  It looked like a coping saw with a fat handle (the handle held 2 D batteries).  To make blades you might want to get a small plug-in transformer so you wont go through as many batteries.

Use the pink foam (like owens "foamula-r").  The interior cell structure is very uniform, it cuts and sands easily, and it comes in thicknesses up to about 2 or 3". If the hot knife doesn't work you can start carving with an electric carving knife (meat carving knife).  You ought to be able to find one at a garage sale for pocket change.

There are also some really quick ways to cut twisted/tapered blades from pvc pipe.  Most folks say these don't perform so well under load, but they sure spin like crazy and they're cheap and quick.

-Dan M

[Sponge]

PVC sounds interesting . The problem with most stuff that people are using here is hard to get. Like the fiberglass resin often mentioned, draw knifes, etc. Maybe it's better in the south of The Netherlands, but here where I live it isn't that common. PVC is available everywhere ofcourse

Let me search around in some DIY shops...

[Norm]

   By all means try PVC it's easy to work with, I smooth and round the edges by scraping with a pocket knife. They spin like crazy, its true that they slow down drastically under load...but with a small motor like you have that shouldn't matter...maybe a 3-6 blader?? there so easy to make with that saw that you have pictured will work,  saw with an acute angle to the work (makes nice straight even cuts)

                    I think you'll really like how easy it is to work with.

                Have fun! ( :>) Norm

[wayne]

Hi

My first thoughts is your motor looks very small and power output won't be that much. And the bearing's or bushing on motor you have to be careful to keep your prop light. My question is I have so many H/D dead units as I work in this field and was thinking or trying the magnetics but sounds like you did not get much power from them. Maybe I will not use them now.

Thks

Wayne

[Ungrounded Lightning Rod]

The problem with most stuff that people are using here is hard to get. Like the fiberglass resin often mentioned, draw knifes, etc.

Got any boatyards or auto body shops nearby?  Ask them where THEY get their fiberglass and resin.

[Sponge]

don't give up on the harddisk engine, I've een once 12v from them. It was in a very hard storm: something broke and the magnets rushed over the coils, they got a little bit damaged, but would still work. But, the windmill is to hard to turn if it's too close to the coils, making more distance will make it turn, but the power output is minimal.

It was my first windmill, with all kinds of magnets, they are very hard to psotiion correctly. I think, if I amde another HD windmill, I would break all the harddisk magnets, so I could fit them more properly. I stacked two of them btw.

Also: Some harddisks (new ones) have smaller magnets. old SCSI/RAID drives have enormous magnets, that are nearly impossible to break apart. if I had 8 of those, or 6 or something, than the windmill would have been definetly a performer!

Check my windmill photos for how I did everything...

Thanks for al lthe comments, I'm probably going to try PVC blades. looks quite nifty and a lot easier.. Still, is the above design really bad? All those kid wind toys use something like this. Those ducks with rotating wings, etc..

[whatsnext]

Are you making a kid's toy or a real generator? If you really like the idea of using flat stock for your blades why not soak them for a while in water and then form(twist) them into a proper blade shape? Boatbuilders use this technique all the time to reshape wood. You may be able to shape all three blades at the same time and end up with a consistant pitch, blade to blade.

[Sponge]

Generator

I was just wondering about it .

[whatsnext]

Now I'm intrigued with the yard duck genny idea. If you built a few of them with a little genny in their gut and then adjusted each one to start generating at a different wind speed you could make a neat wind speed indicator out of them and bug the folks next door too. Perhaps their eyes could light up with little diodes making it possible to gauge wind speed at night.

John.............

[Sponge]

The neighbours have one, it's a little bit annoying . I remember when I was a child, we had a big one, I think the plade was like 1.5 foot, and it worked pretty well.

ack to the foam stuff. IS it simmilar to "PVC-Foam"? I've been wondering what it's called over here in NL. (http://www.netcomposites.com/education.asp?sequence=48 about the foam).

[DanB]

Id suggest that without an airfoil the results might be dissapointing...

but there are plenty of fairly efficient wind turbines which have no twist at all - I think that folks get a bit too concerned about having proper twist on the blades.  Some twist on the blades probably makes them stronger... and they look much neater, and they  are surely a bit more efficient, but I don't think much.  Old winchargers worked great with no twist.  Bergy wind turbines have impressive power curves for their diamter, with no twist.

[scoraigwind]

Those blades are at a coarse angle.  This will turn slowly, which is just as well since it has no airfoil shape and the drag will be bad.

Sharpen the trailing edges and set it at a finer pitch and you will get much better speed.  A small motor like that is going to need all the speed it can get.  Even if it means using a higher voltage, use it because the current it puts out will be very limited.

I bought my last drawknife in a big US hardware chain - forget the name but it is a household word.

Where do the rest of you guys get your resins?  Isn't there a good mail order stie in the US?

[Sponge]

Thanks

The biggest problem right now is finding proper PVC. Since PVC tends to shatter beloew 5 degrees. Unfortunatly, I can only find grey/white PVC. The white PVC has exactly the same description as grey PVC (and looks the same exceptfor color), so I think it's just similar stuff.

3 big companies down.. hm.