Fiber-composites really shouldn't considered as a "one disaster fits all" kind of thing because it's inherently different. For instance, two composites that I know of go like this: water repellent-generic binder - tear resistant - compression strength binder - wear-resistant material is good for certain things but lousy at others, meanwhile, tear resistant - compressed binder - water repellent - generic binder - wear-resistant is good at the things the first is lousy at but bad at the things the first is good at. This probably isn't the best way to explain it, so think of it like this: how you layer the composites and the material you use make a _BIG_ difference in how they are used and how they react to disasterous failures. One could explode from pressure and send pieces flying everywhere, another could not only become stronger due to high pressure, but when damaged keep the hole small and dissipate the pressure in a controlled manner.
However, one problem with composites is lifetime. Regardless of how they're made, most have a limited active life. True, there are ways to extend the life and they're working on making them better, but I wouldn't be surprised if you had to replace the composite air tank on these things every four years or so, if they use composite tanks at all.
As for what they say the energy numbers are, I never go by that. People always quote the best, or worst, possible numbers regardless if they are "best possible lab conditions" or "theoretical extremes." The only numbers I go by are when they have independent labs run the tests on the actual product, then I make sure the labs are really independent. I look mostly at how things would work in the real world and the possibilities for diversity/advancement. The air engine has a lot more going for it in this respect not only because there are better ways of designing the engine (which use less moving parts, fewer resources, less mass, etc.) but also because the air compressors can be made to handle a lot of diversity. For instance, you could have a quick-charge compressor at a gas station that's powered by a high-octane biofuel with a heavily filtered exhaust, or a home unit that's slow to recharge but uses wind and solar power to fill up while you're at work or asleep.
Still, neat as this idea is, I'll believe it when I see it on the road.
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branchandroot
Re: Also
Date: 2008-01-08 01:21 am (UTC)However, one problem with composites is lifetime. Regardless of how they're made, most have a limited active life. True, there are ways to extend the life and they're working on making them better, but I wouldn't be surprised if you had to replace the composite air tank on these things every four years or so, if they use composite tanks at all.
As for what they say the energy numbers are, I never go by that. People always quote the best, or worst, possible numbers regardless if they are "best possible lab conditions" or "theoretical extremes." The only numbers I go by are when they have independent labs run the tests on the actual product, then I make sure the labs are really independent. I look mostly at how things would work in the real world and the possibilities for diversity/advancement. The air engine has a lot more going for it in this respect not only because there are better ways of designing the engine (which use less moving parts, fewer resources, less mass, etc.) but also because the air compressors can be made to handle a lot of diversity. For instance, you could have a quick-charge compressor at a gas station that's powered by a high-octane biofuel with a heavily filtered exhaust, or a home unit that's slow to recharge but uses wind and solar power to fill up while you're at work or asleep.
Still, neat as this idea is, I'll believe it when I see it on the road.