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.