Building a Lenz2 turbine from recycled materials

This is a short instructable showing how I built a small lenz2 turbine from recycled materials.
The Lenz turbine is a type of VAWT designed by Ed Lenz. See here for the full details. There's no generator yet, as I am converting an small induction motor to permanent magnet, this will be covered in another instructable. The turbine is 40 cm diameter and the blades are 35cm tall.

Materials :

An old oil drum
Plywood (I used 12mm, but 18mm would be much better!)
An old rear bike hub
Screws, lots of them. 10 - 12mm pan head and 25mm wood screws
Scraps of 2x6
Piece of mild steel approx 150mm x 30mm x 3mm
Washers to fit bike hub shaft, or thick sheet metal to make tour own.

Step 1 Building the base and bearings

The base is made from 2x6 timber which holds the bike hub. I marked out a square piece of the 2x6 and marked the centre. Drill a hole in the centre the same size as your the middle part of your hub. Then cut the block to size and cut it in half, so that it can clamp around the bearings.

To stop the wood splitting I used a piece of mild steel as a washer under the long screws. Cut it to length and drill two holes either side. Countersink the holes, if you are using counter sunk screws. The screws I used were wood screws about 3" long.

After that I screwed two "legs" to either side. They are about a foot long. These are screwed onto  a piece of plywood later on, to give the base some stability for testing.

Comments

[andyk75]

Very nice instructable, but I wonder why you chose to make the blades open on the outside instead of on the inside?
This way you would have had less hassle with passing the center arm through the blades.
Did you do it for any special reason?

Thanks for your answer
Andreas

[bobby sissom]

your design has inspired me to attempt this on a scaled up version,i envision a fiftyfive gallon drum sized copy on top of my shed providing power for all my shop tools,do you think lighter plastic will allow me to still get away with a bike hub for this size

[Dr Qui]

Hey Bob,

Take a look at my video of my Lenz wing VAWT running in a 10 mph wind and you may think of larger bearings than a bike hub, I think you would be pushing the limits of a bike hub,

I don't even think my turbine mounted in a frame with bike hubs top and bottom would last to long. This thing is seriously scary compared to my last squirrel cage turbine.

My turbine is 1mtr tall x 1.1 wide and the clunking sound you hear is the roller taper bearing riding up the taper and dropping when it gets a strong gust. its lifting upwards of 20kg like a feather. I will need to a taper lock bearing to the bottom of the axle to stop this.

My VAWT is about 1mtr off the ground, on top of your shed a similar sized turbine on bike hubs may end up in next doors garden causing havoc and putting an end to you fun.

I would like to see your finished turbine,

Good luck with you build.

Andy.

[Culturespy]

Wow Bobby, you have to post an Instructable when you build that!

[scraptopower]

That would be awesome! I don't see a problem with the bigger drum and the same bearings. Post us some piccies or an 'ble when your done please :)

[garrett10]

This is so cool! I would love to make one, but how fast is the wind in the video? Thanks!

[scraptopower]

It was between 4 and 6 mph I think, not very much.

[Dr Qui]

Fantastic job, plywood is fantastic stuff in the right hands. My only advice is if you plan to leave it outside is paint it. Paint it until you are sick to death of painting it, at least 3 coats. I only gave my first turbine 1 coat of Yacht Varnish and it was falling to bits in just over a year or so. A friend of mine once met Hugh Piggot and he said that 2-3 coats of exterior gloss was as good as anything to keep the damp out. Are you making your own generator? I would be interested in seeing what you are going to use.

[Bujholm]

I am always wondering - how did you select this size and shape? I mean, flat side 113 mm long - and why not 150 mm? Or why not make it flappier in general, with the round part radius of, for example, 50 (or 150) mm instead of 28 and other dimensions to match?

[scraptopower]

Sorry, I should have mentioned in the instructable. I worked out the sizes from the formula on Ed Lenz's website.

[firstchameleon]

Nice! I can envision a lot of these on the roof of my house (when I find one). Make sure the bearings on the hub you use are good. If you are not sure spin the axle with your fingers it should spin smooth. If it feels 'crunchy' use a different hub. If you are not sure your local bike shop mechanic should be able to tell you if the bearings are good by doing the test hi/herself (they shouldn;t charge anything unless they have to take the hub apart). Most bike shop service areas have old parts they keep (like hubs), usually tucked away in a box under heir workbench. If you don't have a hub; you might be able to talk the tech out of an old hub or two for free , or a little cash under the table (or some cans of liquid made from hops... nudge-nudge-wink-wink). This from a long-time bike shop tech...

[taz699]

Nice :-)

[merijnvw]

Very cool, thanks for sharing

[celalboz]

Great, what size stepper or other generator can this take? what kind of circuit does it need to rectify? same as your AA charging circuit ? Al

[scraptopower]

I don't know yet, I'm still experimenting. Ed's figures seems to suggest I should see about 2.5W in a 10mph wind, but no generator yet!

[rimar2000]

Seems a good design. I regret that in the area where I live is always very little wind, here it is not worth the trouble of making a home unit. And when there is wind, it is swirling and strong.