Friday, 4 April 2014

Wow, I have really not been keeping this blog up to date.
Things are definitely afoot tho. I'm currently in Germany, flying to India in less than a month to start the approtech building trip through Asia. I'll be documenting that (as in, actually documenting it) through a separate blog, the address of which I'll post here when it's up.

Meanwhile, I'll be giving another couple of wind turbine building workshops in Berlin on April 26th and 27th ( after the quite successful ones given in Perth and Melbourne. Also a talk at Sublab, Leipzig's hackerspace, on the 13th.

In other news, the vawt tutorial is now available on ( and of course the SolarFlower website ( I'd recommend viewing via the latter, layout's a bit more useful.

Since leaving New Zealand last September I've spent three months in Western Australia with mum, working on getting the vawt plugged into the airconditioner prototype via a very simple and seemingly quite effective bellows pump made from an old biscuit tin and other bits and pieces:

This seemed like it probably would've worked out reasonably well, but unfortunately as I was preparing to haul the whole apparatus up the side of mum's house I discovered that the brickwork on the roof I was planning to attach it all to is extremely dangerously unstable, and not something you want to be ever standing under, let alone attaching a wind turbine to.
So instead I had to put the aircon back on a vacuum cleaner motor, which then proceeded, due to the new 40mm hose replacing the 18mm, to blast most of the water out of the ground tank and melt a hole in itself.
Mum's since moved house (for unrelated reasons), so when I'm back over that way round the end of the year I'll take another crack at getting all this going. Though it'll probably come up on the trip and get more nicely prototyped somewhere in Asia.

From Perth I was originally going to be heading to Alice Springs, until enough people finally convinced me that going into the outback in December is both dangerous and pointless, as everyone else has the good sense to clear out til it cools down a bit, so instead I flew into Brisbane and headed down the east coast, visiting mates along the way, then flew to Alice mid Feb.

Australia is a mess, for reasons that are too extensive to really go into here, so plans to work in with remote communities didn't really pan out. Instead I played with plugging a photovoltaic panel into the aircon instead of the vawt:

Then drove to Darwin, flew to Germany.

So really things are ticking along until I hit India, at which point it all goes pretty crazy, I should imagine.

Monday, 26 August 2013

Failing so hard and so consistently that the words that come to mind are nesting and recursive.
So I'm just going to go with The Only Failed Experiment Is One You Don't Learn From, and reclassify the whole week as a series of staggering successes.

First, it turns out the wind turbine is waaay too intense to do as a one day workshop where everyone takes one home.
The materials I managed to get sorted, tho that was largely the luck of stumbling over a guy with a couple hundred bikes in his garage and a strong desire to extract nine of the wheels I needed and sell me them cheap.
It ended up seventeen participants instead of the intended twelve, but even with the extra hands there was just never any chance of getting that much work done in that timeframe. Seems things take two to three times longer to make in a workshop dynamic, and that's with folks working pretty solidly.
Live and learn.
So am now looking for a venue to have a second day of it on Saturday and get everything finished off. Figure in future it'll be like I did the Solarflower builds; where we just as a group make one of the thing.

And fail the second; in that I'll be hitching down to Christchurch soon as the workshop's done on Saturday, I've basically run out of time to get the alternator nicely attached to the turbine and tested for output.
The chain drive is I think a good way forward, but tried revving up the benchtop test rig today, powered by the vacuum cleaner motor (with a derailleur sprocket driving a chain driving a bike wheel rim bolted to another wheel driving a chain driving a derailleur sprocket attached to the alternator) and it all kind of exploded a bit. And often.
The derailleur is too small (tho it needs to be that size or smaller to get a high enough ratio to kick in the alt at 1500 rpm), the teeth are too short, and it's made from nylon which just isn't going to hold up for long. You can get metal ones, but having to order them on the internet kind of defeats the purpose of what I'm trying to do.
So I think I'll end up chucking a sprocket set in there somewhere as a wee gearbox, have the rim driving that and it driving a 50mm small but steel sprocket on the alternator. That'll give me about 30:1 instead of 15, and be a bunch more robust.
But I don't have the time to get that in place before Saturday, so it can just go on the worryingly long and lengthening list of things to do in Australia.

Also, I broke a glass.

But screw it, leaving NZ isn't a deadline, prototypes (of which the workshop was one) explode until they don't, and I know many more ways in which things don't function than when I arrived.
And a couple in which they kinda do.

Friday, 16 August 2013

I now know several ways in which rope belts don't work, and none in which they do.
Last week and a half I've been trying to attach the turbine to the alternator in a way which is a) not going to slip, b) runs smooth and easy, and c) isn't going to chew holes in itself. There's several ways I've found which will satisfy any two of these, but none that'll do them all.
So I've pretty much given up on that, and have gone for what I should've just done from the start, and used a bike chain. Or at least, one and a half.
I didn't want to do this for the two reasons that it's a little more resource intensive than I'd like (but at this stage, screw it), and that the smallest sprocket I can use, the one off the derailleur, only gives a gearing ratio of 15:1 from the turbine's bike wheel rim, and I was under the impression I've been needing at least 25:1 to get the alternator up to speed and kicking in at a low enough wind speed.
However some actual research has revealed that most car alts come in around one thousand to fifteen hundred rpm, not the twenty four hundred I was led to believe.
So 15:1 is actually perfect and I can use the chain after all. It's definitely and by far a more robust solution.

So that's all in place in terms of the benchtop test rig, which tomorrow I'll get the vacuum cleaner motor back on (after it rather catastrophically failed on the first firing up and sent a length of rope at my fathers head with not inconsiderable speed, luckily he's got fairly snappy reflexes) and we can get the thing tested before strapping it all on the back of the car and doing some actual power output runs.

That'll have to wait a week tho, as I'm off to Nelson on Sunday to get the construction workshop prepped for the following Saturday. Then it's back here for a week or so, then down to Christchurch for similar, then flying out to Perth.
Busy busy.
As according to the universal constant I've got exactly half done of what I'd wanted to, but it's all good. Just glad to be getting anywhere at all, really.

Sunday, 21 July 2013

This is the second test of the super low cost (NZ$30), easy to construct (6 hours for two people) build of the Lenz2 vertical axis design, with the intention being of surviving sustained 100 km/h winds. I didn't log and graph the RPMs on this run as I did in the last, as we had a gusty tail wind which kind of messed up the data. I'm pretty happy with 105 km, and the next step is attaching a car alternator with a rope belt and getting some usable power off the thing.

Thursday, 18 July 2013

Well that was emotional.

Had what I hoped to be the final destruction test today, which I've been a little nervous about as I need to sign off on the thing being able to take 100km wind so as to let the Nelson Environment Center know I'm able to go ahead with the first construction workshop, and they need at least a month's notice.

She peaked at 105k, backed off and held 100 for maybe ten seconds, and then catastrophically failed all over the road and very nearly took out a kid on a bike.
You can just make him out at the top left of the debris field photographed below.

So, success!

I'll of course be posting the video soon, but cursory examination has it looking very much like what gave is the bolts, or rather the alu around them, which connect the vanes to the wheel rim. Which is by far the best thing to have failed, as it's the easiest bit to make stronger.


Wednesday, 10 July 2013

Realised the reason for the thing being off center was a rather dumb and unnecessary mistake of my own, won't bore you with the details, am today fixing. Also looking at ways to economise on constructing the vanes, timewise. Reckon there'll be some economy of scale doing three at once, can hopefully get it down somewhat from the current hour forty per, which is frankly already pretty much ok.
Picked up a car alternator yesterday for $40, which is pretty good, and had a look at the Nelson Environment Center where I'll hopefully be doing the first construction workshop mid next month. They want at least four weeks warning tho, so I'm going to have to hustle getting it all signed off on and good in the next week or so.

Monday, 8 July 2013

Well that didn't go well.
I've made another turbine with an aerodynamically better and much! stronger vane design, and today did another Definitely Not Destroying My Father's Back Windscreen speed trial. Thing didn't even make it to the testing road. Twice. First time the bracket holding it to the pole was too small and chewed the wood, so we had to head home and quickly make up a better one, second time the bloody bike axle bent.

It was vibrating and wobbling like crazy, I managed to put two of the vanes on rather unaligned and somehow that made the difference between the previous 80 km/h and everything's fine, and a bent axle at 65.

So I'm going to align and center the vanes like they should be, and add another three more on the bottom of the wheel so that the force is all sideways rather than levering the thing against its contact point.
This was always the plan anyway, I just didn't think it would be necessary for this test.

Tomorrow we're heading into Nelson to, amongst other errands, find a car alternator to be getting actual power of the thing, and an old vacuum cleaner motor to rev up and test the alternator. And a couple more spare bike wheels to mess up.
Also visiting the Nelson Environment Center, where I'm supposed to be giving a construction workshop on all this soon, if I can get the damn thing to work.

Doing stuff is haard.
Can't believe I went through almost two years of this malarky with the solarflower.

Thursday, 4 July 2013

Other Tech.

Today I finally started documenting other bits of tech that I've been thinking of and possibly prototyped:

I'll be adding to it over the next weeks and months.
The idea is that the project will move to a point where the solarflower is one device of many, and this is the start of the process of getting other things documented, tested, tutorialised, and made generally available and useful.

Tuesday, 2 July 2013

More accurate wind power average calculations.

Been trying to get this trough to Wolfram Alpha, but their forum doesn't really get used and the FB page, like all pages now, is pretty much set up for ineffectual broadcast only. I'll put it out here to see if any of yall has input.

Basically there's a problem with how most people figure out the viability of home wind power in their area, which is that they'll take the average windspeed (let's say 15 km/h), figure a turbine's power output at that speed, and thereby see how much the turbine will put out per week/month/year.
And if the wind's blowing at a constant 15 km/h then that will be accurate. Let's say about 12 watts for a typical meter diameter turbine.
But, if the wind's actually not blowing at all half the time (0 watts), and at 30 km/h the other half (98 watts) then the actual average power output is gong to be 49 w, not 12. If it's 60 km/h a quarter the time it'd be 195 w.
It's because wind power goes up by the cube function of its speed. A little more wind makes a lot more power, and just taking the average (mean) speed doesn't at all accommodate this, so people are making the decision on whether to invest in a turbine based on erroneous information.

So what I'd like to see is a calculation in Wolfram whereby the windspeed data for an area is graphed for a given period, the area under the graph, ie the total wind power, is calculated, and a windspeed average given such that that's how fast the wind would have to be constantly blowing to give you that much power.
People can then multiply that by the output of their turbine and see if it's going to be a viable investment for them.

Sunday, 30 June 2013

First destruction test of the vertical axis wind turbine.
This was mainly to see what kind of winds it would take unloaded, and where would need strengthening. I also measured revs and tip speed ratio.
Overall it held together very well, mounted on the back of the car (slightly insane, but effective) at up to 80 km/h, the only point that seems to have failed is the area where the flat of the vane meets the curve, as shown at the end of the video. This is due to the flat flapping and flexing, which is what I'll now fix with the next build.
I'll be getting more plates this week, rebuild with an improved design, and retest (hopefully over 100 km/h).

Wednesday, 20 February 2013

$10 wind turbine prototype

The SolarFlower has pretty much been the flagship bit of tech for what is becoming a larger project.
So far I've documented the non electrical temperature regulation system and the mesh reflector dish, and in the next couple months I'll hopefully be adding an air coolant fridge/freezer, lattice polytunnel, loudspeaker linear alternator, and some kind of way of generating electricity from heat (probably along the lines of a thermoacoustic alternator, or liquid piston steam engine.) All will of course follow the angle of being open source, scrap makeable with basic tools, and be documented and posted to the Solarflower website.

But what I'm working on now is a vertical axis wind turbine.

 Providing the thing doesn't destroy itself in actual wind, this is so far a very cheap, easy, quick, and structurally sound way to make this turbine design. I'm using Ed Lenz's Lenz2 design, which has been tested at about 40% mechanical efficiency.
Materials used:
5 74 x 60 cm aluminium printing plates (£1 each = £5)
~100 pop rivets (~£5)
Bike wheel (free)
6 M3 nuts and bolts (negligible)

Tools used:
Rivet gun
Craft knife
Straight edge

Time taken was 2-3 days on my own, but that's prototyping which takes vastly longer than making something known. I'd expect it to come down to easily a day for one person at pottering around speed.

Power output (mechanical):
Still have to see if the thing survives, but according to the calculator for this design:

20 km/h wind = 28 watts
30 = 90 w
40 = 220 w
50 = 420 w
60 = 730 w
70 = 1,155 w

It's now set up at a mate's place out of town and we're waiting for some serious wind to come through to see if any structural improvements are needed. When I'm comfortable in signing off on the design I will tutorialise and post it to the website, and maybe look at doing some workshops on it here.

More updates to come.

Sunday, 3 February 2013

Quick teaser for upcoming big news for the project:

View The SolarFlower Trip 2013 in a larger map