DIY Vertical Axis Wind Turbine

After watching this video on recycling 12V rechargeable drill-screwdriver mechanisms to generate DC power to recharge batteries...



...I decided to design a recycle-built VAWT to test the idea

I got my hands on a scrapped rechargeable drill, stripped the body-shell and the rest of the electronics (including the blocking-diode across the motor's +/- terminals) and tested it by powering the drill-mech with another cordless drill running at full-charge. When connected up to the multi-meter this gave a reading of just over 11.5V at around 150-200rpm




Rather than go for the split-drum Savonius type I've decided too go for a more elegant Helix design, inspired by this idea...



The 'ribs' that will form the helical structure were cut from scrap 3ply corrugated cardboard used to transport flatpack furniture, I've got almost 30 blade-templates cut-out so far and have a dilemma over which would be the best arrangement...

Double helix?



Or a triple helix?




This is an individual 'wing structure' that needs a few more steps before its finished...



The plan is to hot-glue all the cardboard layers together and smooth modelling clay over the surface to take-out the steps in the layers and provide a uniform aerodynamic flow.

Once that is done, the whole wing will be wrapped in fibre-glass mat and resin to create a mould, and when split open, should be able to use the mould to cast enough blade-sections from expanding polyurethane foam (such as the cans used to repair/inflate car tyres by the roadside) to stack into a 2-3mtr tall helical VAWT structure...

...photos of casting/mould-making, plus the rest of the mechanical bits to come soon!

The drill idea is nice. Got the gears right there. Not sure about load though. A little fan like in the video is only 30 or 40 watts. Around 3A@12V, assuming the fan was running at full speed. If that's the best a typical drill motor can do it'd only be practical for survival/camping situations or powering small systems like well pumps or weather stations. You could always build multiple turbines and wire them in parallel to provide usable power for off-grid or grid-tie type setups. Say you have a 200Ah battery bank for a very small home. You only want to discharge 100Ah max per cycle to preserve longevity. Just to make it easy assume 10 hours of full wind per day, with losses, so 4 turbines to recharge. Definitely something to use in combination with solar or humans.

The drive axle will have to be quite tough. On a stormy day there will be a lot of stress placed at the point where it enters the stand. But it's much more attractive and gives a more artistic appearance than a big mill.

I vote double helix to catch the most air but with how large you're talking about (2-3m!) I wouldn't bother with little drill motors. A good sized DC motor at least 150V with a gear set designed for wind turbines would make best use of the force generated. Then you'll probably just need one.

WOW!
Awesome..
I'd never even seen this design before you posted the video.
You could get four of these up in the average back garden and two on the roof.

Wind is something we're seldom short of in the UK.. Must be the Spicy Punjab on Westgate road in the North East.

Edit add..
You can use GRP coating to 'finish' off the PU Foam blades to give a weather proof coating.
You can get a 'Gel coating' paste from boating or windsurfing stores anywhere if not just a DIY..Just a thin coating should do and a bit of a polish..

[edit on 5-6-2008 by AGENT_T]

Yup! I printed out the PDF of the home sized turbine and put it on the fridge. It will be in my backyard in a few years i reckon. I would love for there to be a huge tax writeoff as well.


I read the OP with interest but I need and electrician guru to get me tinkering with that stuff.

[edit on 6/5/08 by stikkinikki]

thanks for your input folks

will be able to have a proper workshop session this weekend and go on the hunt for lots more cardboard and finish laying up the blades, ready for glueing and fibreglassing...

also on the scavenge list is an old mountainbike...the front and rear chainsets and shift-mechanisms are going to be used to build some kind of greabox (not sure how yet tho...) and the rest of the frame and bottom bracket crank assembly can be re-cut and arc welded to make the frame and base-bearing...this point is already designed to take heavy rotational loads from the loads on the pedal-arms so should be robust enough if the blade sections are all balanced

the project so far..

...and lots more cardboard to hack to carve the other 100 to finish the section for casting



...will update with more photos and stuff at the weekend, but please, keep the suggestions for stuff coming...

smith

[edit on 5-6-2008 by citizen smith]

Go Citizen!

With my up and coming Solatronic Generator and your Windatron we can really show folk what us Brits can knock up

Necessity is the mother of invention!

Hey citizen smith!

Once again youve give us some great vids to rack our brains over, I like your 3 blade assembly cannit wait to see the finished model!

Keep up the good work!

*

nice job
can i make a small suggestion?
just build up 1 blade, then take amold if it, and cast as many as you need from light layers of glass cloth and resin
should be better to able to balance them, all be excatly the same, and can make several sets right off the bat
might be less work then doing 3 full sets, and less hassle aswell
anyway, keep us updated

update II

after a day of mostly carving-up cardboard i'm beginning to wish I'd paid attention to my maths teacher at school...the one time in my life when I actually need to know how many 'x' to take from 'y' and give to kevin who has 24 oranges...

I'm now back to the twin-helix-blade design as I now have 60+ blades cut to the original 2-blade template and can't be doing with more work than necesary...i blame cold beer and left-handed cigarettes for that 3-blade sidetrack idea...dammit

more photos and a proper write-up to come soon!

I'd just like to add that for those of you who are mechanically/electrically minded or who have a bright idea and wish to contribute, whatever you post here, I intend to compile into a freely available Instructables project

survival is about the sharing of ideas for the betterment of all, is it not?

karma

[edit on 7-6-2008 by citizen smith]

You must use only 2 "blades" if the wind direction in your location it's usually the same and the wind speed its high. If you're planning to set up the turbine in a place with a lot of changes of wind direction you must use the 3-blades model, because it will capture better the wind in every direction but it will run slower than the 2-blades model.

I don't like the savonius class turbines, there are other designs that work better on vertical axis and they are not very expensive/hard to build.

If it's your first time trying to make a wind generator, don't give up if the first time doesn't work like you want. It took me four attempts until I get my windmill working properly. If you live in the countryside consider taking a lightning rod, preferably from a church or a gov building (it's more funny) and add it to the top. The voice of experience it's talking here, I've lost the windmill and a good alternator because of a lightning.

Good luck, I'll be around seeing your progress

reply to post by nsk123


Hi, sounds like good stuff, d'you have any fotos of the windmill-setups that you built? would be great stuff to add to the thread!

OK, this is awesome. I especially like your concept of using cardboard stacked to create the turbine. Are you planning on fiberglassing the completed assembly to reduce friction? Fiberglass epoxy isn't expensive and it's very tough and easy to work with.

I know that chimneys tend to generate their own wind in most cases, due to the higher velocity winds being faster in the higher atmosphere. Now you have me thinking about making a chimney to power a turbine.

Sheesh, that's all I need, another project. OK, back burner for now, just let me know how yours works out, OK?

TheRedneck

reply to post by TheRedneck


The more I work on the project, the more I'm beginning to realise just how mathematecally complex a structure a helix is to make out of cardboard or other materials...the principle behind the idea is that as the turbine spins on its vertical axis, incoming air is drawn upwards in a spiralling pattern, creating a rotational spiralling upward draught that would stabilise the spinning structure...the more blades added to the helix, the greater the rotational stability, and less wear on the bearings and drive mechanism to the generator.

Also, I've realised that for a first model I'm going to have to build the whole thing out of laminated corrugated cardboard, bond all the sections together in a helical stepped-profile and then fibreglass the lot...

...what fun is engineering if things go right all the time, eh?

reply to post by citizen smith


i love the idea and design of the blades it is so simple and yet elegant ant it does not need to stick up 40 to 100 feet in the air .simple and yet beautiful.as to the blades being made up of cardboard and fiber glassing it .we use a heavy ribbed plastic piping in the factory where i work it comes in 12 to 24 inches across the center.the ribs are 1/2 x 3/4 inches, if we cut one in half length ways we could twist and form it to the exact shape shown in your video.if we silicone spray the outside so nothing sticks to it we could use it as a reusable form.buy using stainless steel tig welding rods -which are small and yet strong and light weight and they don't rust.why not use the ods to bend up a frame fitted to the outside of the 1/2 tube tig it together them lay it on a bed of glass resin over the tube then apply another thin coat of resin on top -fast simple and easy and very strong attaching to the uprights would be simple

Good idea. Have you seen these? I thought they might be useful as some inspiration for you.


www.turby.nl...

Also, for a biodegradable alternative to fibreglass, check this stuff out, called Zelfo.
www.zelfoshop.com...

I look forward to seeing the results.

reply to post by citizen smith


not so many years ago tsc farm supplies used to sell wind generators to the farmers so you might like to check out the local farm supply places for one , if you cant get one there find -princess auto in Canada-they have an offshore which runs off of a gas motor -not needed try some type of gearing or belts and pulleys ,or chains ans sprockets to increase the out put shaft's speed.you might even try a car or trucks alternator and generator with a battery bank -deep cycle -these generators come in all sizes from 1 outlet at 120 volt cost $133.00 plus taxes to one with 4 120 and 1220 and 1 12volt outputs for $699.00 when on sale-you would only need to drive 1-120 motor at 3600 rpm to run the big one and they come bigger.

reply to post by picrat


I like your thinking, but s.steel tig rods would be incredibly expensive to use for this project...the idea is to beg/blag/recycle all the parts needed with no material costs at all if possible...i'd rather use 1/32" dia. 20" long bamboo kebab skewers that would do the same job

The cardboard for the blades is scavenged from local superstores (just ring up and sweet-talk them into the idea so they'll keep it for you rather than them running it through a compactor)

I'm trading a ripped-out central heating pipe and radiator system that i'm replacing, with a local scrap-merchent for bike parts and other handy mechanical stuff to cut down costs too.

The only thing I've spent any money on so far is for craft-knife blades for carving cardboard, and fibreglass matting/resin/hardener...not bad for £20 so far total costs!

reply to post by citizen smith
Yeah, the math for a wind blade is pretty awesome. It's based on the idea that the air moves at a constant rate through the turbine at all points, even though the blades are not moving as fast linearly near the center shaft compared to at the edge of the blades.

There have been a couple of times I wanted a set of blades similar to what you are creating, but for the life of me I couldn't figure out how to make them, just how to design them. That's why I love the idea so much.

And engineering is fun, period.

TheRedneck

Originally posted by babylonstew
can i make a small suggestion?
just build up 1 blade, then take amold if it, and cast as many as you need from light layers of glass cloth and resin
should be better to able to balance them, all be excatly the same, and can make several sets right off the bat

I've taken you up on the idea

I've used hot-glue to bond 40 of the wing sections into a single blade as you suggested (as in image #4 in the OP) and step-rotated each section by eye to make a 250mm high blade-unit with a guesstimated 60* twist

The next step would be to use modelling clay to smooth over the stepped cardboard profiles to give a cleaner airflow over the wing surface, and then a mould created from fibreglass...

similar to the 'helix-wind' design in the youtube vid, of using just reinforced flat-surfaces, the same surface shape could be cast from either the outer or inner face of the wing for a truely lightweight turbine sail


I also seem to have blown the drill-motor somehow during the voltage output tests and now barly registers on the multimeter when the chuck is cranked, so I now have to find an alternative junked DC motor to use that could be geared up using a mountainbike drive-train assembly

...any electro/mechanical suggestions would be much appreciated!

reply to post by citizen smith


I'm watching this thread with Great Interest, Citizen Smith, and I wish you the best on this project.

I have shown this to several of my friends, and we are all amazed.

I cant contribute anything much at this point, but I totally understand your drive to complete this blade.

The modeling clay is brilliant, to smooth out the steps.

I can say this in all honesty, if you keep posting results, we will be copying your design immediately.

What was ever decided on the "spray foam" insulation for the final blade structure? I still like that Idea.

Also, would it be possible to build a "rib cage" type framework out of light plastic or aluminum, and cover that in canvas, silk, nylon or some other flexible material? ( eliminating the cardboard cutouts for the "FORM") I see you mentioned Bamboo Kabobs for rigidity earlier.

It seems to me it might be lighter weight, and you could actually SEW it to the framework. Something like a "FISH BONE" but twisted to make the blade shape. Of course it would need to be relatively rigid, ( the BASE framework ) but that "rigidity" could almost be "sprayed" on the fabric, in a light coat of "epoxy" paint, or "clear cast" acrylic WITH a good rigid framework.

I keep seeing these "wind mobiles", that people hang on thier patio. Wire frame covered in nylon... spins really fast....

Anyway, just thinking out loud.

Keep up the Great Work! You really sparked an interest over here.

Best Regards,

Blitzkreigen


One More Quick Suggestion.....

Instead of using fiberglass to make a Mold, why not use Plaster bandages, like for making a cast on your arm? Seems like it would be easier, faster, and less smelly to use plaster of paris, and gauze wrap. I know you already bought the Fiberglass, but its just an idea.



[edit on 12-6-2008 by Blitzkreigen]

[edit on 12-6-2008 by Blitzkreigen]

[edit on 12-6-2008 by Blitzkreigen]