Updated 5 Sept 2022
Developed by: Daniel Connell
English Tutorial Text: Daniel Connell
Tutorial Animation: Daniel Connell
Contents of this tutorial:
Description
Tools
Materials
Resources
Step By Step Instructions
Configurations and Applications
The turbine uses the 35-40% mechanically efficient Lenz2 lift+drag design. It is made almost entirely from scrap materials, and should cost about $15-$30 for the six vane version, which can be made by two people in four hours without much effort.
The three vane version has been successfully survival tested to 80 km/h sustained winds and the six vane version to 105 km. Both will do more, but exactly how much has not yet been ascertained. The current longest running version has been up since early 2014, through reasonable storms, with no noticeable wear and tear as of yet.
Full power curves have yet to be calculated for this particular build, but according to Mr Ed Lenz's calculations a six vane at 0.91 meters diameter and 1.1 meters high with a 90% efficient alternator should produce at least 130 watts of electricity in a 30 km/h wind, and 1 kilowatt at 60 km/h.
The materials listed in this tutorial are to make the six vane version. Halve everything except the bike wheel for three vanes. |
Power drill |
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4mm and 5mm Metal Drill Bits |
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Craft Knife or Stanley Knife / Box Cutter |
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20mm x 20mm angle aluminium About 1 meter long, an extra 30cm length is also handy. To be used for ruling and bending. |
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Tape Measure |
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Pop Riveter |
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Marker Pen |
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Sticky Tape |
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4 Clothes Pegs Springy or the other kind. |
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Computer and printer Low quality black and white is fine. And 2 pieces of A4 or US Letter paper. |
| Optional: |
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7mm Socket / Nut Driver |
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11 Aluminium lithographic offset printing plates These are pure aluminium sheets used in a printing process fairly common with newspapers and packaging. A medium sized printing company may recycle hundreds of plates every week, so it's usually easy to pick them up cheap. Ring around any local companies offering offset printing. Any size, thickness, or type is fine as long as they're larger than 67cm on the long axis. They'll probably be quite inky when you get them, it washes off your hands easily enough with soap and should be non toxic. |
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280 4mm Diameter Pop Rivets |
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30 M4 Countersunk Head Bolts/Machine Screws About 12-20mm long. Strictly speaking only 9 need to be countersunk, the rest can be pretty much anything, such as hex head or socket. |
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30 M4 Nylocs/Lock Nuts These are nuts with a ring of nylon to stop them rattling loose. If you can't find these a normal M4 nut with a spring washer will do the same job. |
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48 Small Washers 4mm inner diameter to fit the pop rivets and bolts, outer diameter about 10mm. |
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42 Large/Penny/Repair Washers 4mm inner diameter to fit the pop rivets and bolts, outer diameter about 20mm. |
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2 x 26 Inch Bike Wheels Exactly how bike wheels are measured is slightly complicated, basically you want one which is about 58cm total outer rim diameter, give or take. The wheel should: ~ Not be quick release ~ Have a normal thick axle (about 10mm diameter) ~ Have 36 spokes ~ Run reasonably smoothly ~ Have enough axle showing to attach to your pole mount, at least 3-4cm. ~ Only needs gears if you're going to be running a chain off them, which you probably aren't. It may be helpful to take the wheel hub apart using spanners and a bike cone spanner and give the bearings a bit of a clean and re-grease, and to extend the axle as much as possible on one side for attaching. If you've not done this before take it along to your local bike servicing place and they'll be happy to show you how. Shouldn't be necessary tho if the wheel runs nicely enough and has enough axle showing. |
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12 bike wheel spokes Any length, type, or condition is fine. |
Resources:
| Print Templates:s | 3D Model (zipped) |
VAWT_template2022_A4_01.pdf VAWT_template2022_USLetter_01.pdf |
Rhino .3DM (41.2 MB) |
Step by step build instructions:
These relate to the animation to the left.
Step 1:
Download and print the two template files from the links above. Make sure they're printed at 100% (300 dpi). When printed measure the distance between the dimension arrows, it should be 10cm on both pages. If it's a couple mm off that's probably ok.
Tape the pages together so that the 10cm dimension marks overlap as closely as possible. Best way to do this is on a window pane during the day, so you can see both pages showing through.
With a craft knife and the angle aluminium as a straight edge, cut out the outer border of the template.
Any time you're cutting, always make sure your other hand is never in front of the knife, so if you slip you're not going to slice yourself. The angle aluminium is good for this, as the vertical bit effectively shields the hand holding it.
2:
Take an aluminium sheet and measure a box 42cm x 48cm. Draw a line half way up the 48cm length so you have two boxes measuring 42cm x 24cm. Score the outer lines with the Stanley knife and straight edge. You're not trying to cut through the metal, just create a line that can then be popped out later. A good method is to score once lightly, then a second time a bit deeper.
Do not score the 24cm halfway line.
Flex the metal so that it bends at a score line, then flex back the other way. Do this a couple times and it should split. Do the same for the other score and remove the outer metal.
3:
Tape the template to the metal rectangle (from now on to be referred to as a 'former') so that the long edge of the paper sits on the middle line and the right hand edges of both line up. Don't worry if the other edges don't align perfectly.
With blade and straight edge, score out the template curve, including the triangles at each end. It's not essential that this be 100% perfect, but try to get the first one reasonably nice as you can then use it as a template for the rest.
Score, flex, and remove the two triangles of metal outside the template.
4:
Mark the centers of the little circles on the paper template with a marker pen so that they're visible from the other side and flip the paper over so that the printed side is down on the other half of the former, keeping the long edge on the middle line. Retape so it doesn't shift.
Give the curved score several light flexes, near the edge, and tear it out. Remove the two small triangles. Be careful not to bend the unscored metal too much as you're doing this as it may weaken it.
You now have your first former. Repeat steps 2 through 3 so that you have a total of 12 formers. You can use the first former as a cutting template rather than the paper. On three of the formers have the 24cm line drawn on the front, the other three on the back.
5:
Take all 12 formers and peg them together so that they are as nicely aligned as possible.
Use tape to attach them if you don't have clothes pegs.
Drill each of the 18 holes through all 12 formers with a 4mm bit. It can help to put a bolt through the first hole to keep the formers from shifting around as you drill.
Remove the template and unpeg the formers.
Place a former with the 24cm line slightly overhanging the edge of the table. Place the straight edge on the middle line and bend up to 90 degrees. Repeat with all 12, with 6 formers bent shiny side up and 6 bent shiny side down.
Put the formers aside.
6:
Take an aluminium sheet and flatten out any bends in the metal. Cut the long edge down to 67cm.
Draw a line 2cm from one of the 67cm edges, flip the sheet over and draw another line 2cm from the opposite edge on the other side of the metal.
repeat with 5 more sheets and peg all 6 together so that each drawn line is aligned to the edge of the sheet above it.
Mark the edge at 4cm, 6, 8, 10, 18, 26, 34, and then every 2cm up to and including 64cm
Keep in mind that one side has a score at 4cm from the edge, the other at 3cm.
Flip the sheets over, making sure they don't lose their alignment. Mark and score the same as the first edge. Make sure both have the 4cm gap on the same edge.
7:
Tap the sheets on the table so that they are aligned on top of each other.
From the 4cm end draw a vertical line at 19cm from the edge, and one at 33cm from the edge.
Mark each line at 3cm and 20cm from both ends.
Drill all 6 sheets with 4mm holes at all 8 marks.
Unpeg the sheets.
8:
Place a sheet so that the second 3cm edge is overhanging the table. Place the straight edge on the second score mark in and triangulate the edge as shown in the animation.
Triangulate the 4cm edge in the same way.
Pre-bend the sheet so that it'll be easier to place in the formers. Don't bend it so tightly that you crease the metal.
9:
Flip the sheet upright and insert into the curve cut into a top former (the uncut half of the former should be pointing upwards).
The best way to do this is to first place the 4cm edge triangle into its slot, then the 3cm edge, push in the inner flap, then work the rest of the sheet through the cut.
Fold down the tabs so that the first three at each end fold out, then alternate. You will probably need to give the score marks a couple of flexes before tearing them, or use pliers if they're being particularly stubborn. If you find that you've bent a tab the wrong way leave it as it is, bending it back the other way will weaken the metal. Make sure the three long tabs alternate to each other.
Push up the former so that it's level with the bent flaps.
Place 2 bike spokes in the fold of the former and bend it closed. If you squish the edge of the metal around the spoke with pliers or similar it'll stop it from falling out.
Flip the vane, place the other former, and fold down the tabs in the same manner.
10:
Slice and remove the former's two outer corners. Cut the smaller triangle level with the edge of the other former half, but give the larger triangle a 2cm offset, so that it overlaps.
Repeat for the other former.
11:
Take one of the offcuts left over from cutting a former. Cut out a strip which is 7cm wide and then cut 4cm off the long length.
Triangulate the strip as shown.
Mark the rough middle of each end of the 3cm wide face with a line a couple of centimeters long.
12:
Place the triangulated strut inside the vane so that the 3cm face sits on the row of drilled holes closer to the back edge. Sight the drawn lines through the top drilled hole to check that it's centered.
Drill the strut through the hole in the vane and attach with a rivet. Repeat for the bottom hole, then the two in the middle.
13:
Take a fresh sheet, smooth out any bends, and cut the long length down to 67cm, then cut in half so you have two pieces 33.5cm wide.
Cut off 4cm from one of the short edges of both pieces.
Repeat so that you have 6 33.5cm sheets. Align and peg all three together.
From one of the long edges, draw three vertical lines at 1cm, 9cm, and 19cm.
Mark these lines in from both ends at 1cm and 20cm.
Drill a 4mm hole at each of the twelve marks.
14:
Mark the sheet at 5cm in from the opposite edge.
Triangulate the edge as shown.
15:
Place the half sheet inside the vane so that its un-triangulated edge is aligned with the vane's back edge. It's ok to have a small gap or bowl at either end if it doesn't fit perfectly in the vane.
Drill and rivet the row of holes in the half sheet closest to the back edge.
16:
Stand the vane upright. Push the half sheet's triangulated edge in and forward so that it's against the other sheet and somewhat tight over the strut.
Drill through the row of holes on which the half sheet's triangulated edge is sitting and rivet in place.
17:
Drill through one of the middle holes in the half sheet's back most row, making sure to keep the drill reasonably straight, and attach with a rivet and washer, so that the washer is on the inside of the vane. This bit is much easier with a second pair of hands. Try to keep the washer fairly flat on the metal.
Repeat for the other three holes.
Drill, rivet and washer the remaining row. The half sheet should be tight across the strut. You should notice that the vane is now a lot stronger and more rigid.
Fold up the overlap on both formers to 90 degrees.
18:
Drill through all the holes on either one of the formers.
Drill into a small block of wood or rolled up tube of aluminium offcut so that the metal doesn't get pushed in and so that you don't risk drilling your hand.
Rivet each of the holes except for the ones marked.
It's very easy on some of the holes to just push the inner layer of metal away with both the drill and rivet, so check that each is properly holed and attached. If any aren't you may need to drill out and replace the rivet.
Repeat drilling and riveting on the opposite former.
19:
Take your bike wheel. Drill three 5mm holes evenly spaced around the rim. Your wheel should have 36 spokes, so drill a hole every 12 spokes. The hole should be fairly close to the rim edge.
Poke a countersunk head M4 bolt up through one of the holes in the wheel and through the back most unriveted hole in the bottom former of a vane.
The purpose of the larger hole is so that the head recesses further out of the way if you want to put a belt around the wheel rim to drive an alternator or similar.
Place a large washer and a nyloc on the bolt. Make sure the bolt is against the bike spoke you put inside the former's folded edge, and the washer is over it. This is so the bolt, and therefore the whole vane cant rip either sideways or upwards off the wheel.
Don't fully tighten the nyloc yet.
Align the vane so that the other unriveted hole sits near the edge of the wheel rim and mark with a pen through the hole, and also the unriveted hole in the middle of the former.
Rotate the vane away so that you can drill the two marks.
Move the vane back and lock down with two bolts, large washers, and nylocs. Fully tighten all three. This is where the 7mm socket / nut driver comes in handy, as tightening these by hand is a bit of work.
20:
Repeat twice from step 8 to assemble five more vanes from your remaining formers and sheets, attach two more to the top of the first wheel, and the last three to the underside of the second wheel so that all six can connect to each other, facing in the same direction.
Bolt all six vanes to each other, in a staggered overlapping configuration, with the rear unriveted hole next to the bike spoke attaching to front unriveted hole of the vane behind it. Use two large washers per, one under the bolt head, the other under the nyloc.
The remaining unriveted holes can now be bolted to each other in the same way. It should be fairly obvious which connects to which as they'll be sitting more or less on top of each other. Moving them into alignment will force the vanes into a balanced six way symetrical hexagon.
Congratulations, you've made a wind turbine!
These are some potential ways to attach applications to your turbine so that it can do useful work. There's not really a one size fits all answer to exactly what or how you should go about this, as it will depend heavily on your particular situation, and these possible solutions are meant only as a guide. If and when you get to this part of the process please email me directly or check out the Facebook group, where the community can help you build what you need and you can follow what others have done already. Most builds are pretty straightforward, and it's all been done before.
A: Hoverboard Wheel
This turbine can be plugged into and used to power a variety of applications, such as mechanically attaching a pump in order to move water and compress air, but you're probably going to be using it to generate electricity to charge batteries.
One of the easiest to source solutions for this is to use a permanent magnet (as in, it uses actual magnets rather than electromagnets) direct current motor in reverse as a generator.
Probably the best option for this is the wheel off a hoverboard/balance board/segway, as they are pretty powerful, hard wearing, weather sealed, three phase AC, do good volts per rev, and can be usually found for about $£€20-30 second hand in the local classifieds in regions with those kinds of consumer items.
Probably the easiest way to attach and drive this is with a ~2.5m alternator belt from a van/truck/bus/large car, looped around the bottom bicycle wheel of the turbine and the hoverboard wheel minus its tyre, with a tensioning system as shown in the animation. You'll probably want to attach a loop of nylon strap or leather around the bike wheel, for cushioning and grip.
B: eBike Wheel
The perfect solution for generating electricity from the turbine is to use an electric motor hub bike wheel. If you can find one. The design uses a wheel anyway, and pretty much every aspect of power inputs, outputs, rpms etc fit quite nicely into a direct drive ~300 watt eBike wheel. All you do is build the turbine on it and plug the wires into your electrical system. Unfortunately however, outside of a few countries they can be difficult and expensive to source.
C: Motorbike Alternator
In parts of the world where the above two items aren't as readily available, probably the best option is the alternator (also called a stator) from a motorbike, scooter, or tuktuk. These aren't usually quite as powerful or high volting as the others, but still do a fairly decent job. A general rule of thumb is the bigger and slower the bike, the more volts it'll do per rpms, which is what you usually want.
The one main drawback to these is they don't have their own bearings. I usually mount them on the hub from a bicycle wheel, as documented in this tutorial:
youtube.com/watch?v=jLVcbd0C9Ns
There are two main ways to attach these to the turbine; with a belt, similar to Configuration A, or with a short loop of bicycle chain from the sprocket set on the turbine's wheel to the one on the alternator assembly. The former will give a lot higher revs and therefor volts due to being geared up, but an advantage to some bike alternators is they have a high voltage coil, which usually does about ten times the volts per rev of the other coils, but at a tenth the maximum amperage rating (ie, before it melts). But if you're only wanting say 10-15 watts to charge some phones or USB batteries for LED lighting, then this should probably work ok, and since the resistance on the turbine is so much lower than with other options you should hopefully be able to generate power more or less constantly, even in low winds.
If you have any questions please email me at opensourcelowtech.org@gmail.com, or join the $30 Wind Turbine Makers Facebook group.