Alt-BEAM Archive
Message #12807
To: beam@sgiblab.sgi.com
From: Blumojo13@aol.com
Date: Thu, 30 Mar 2000 11:09:36 EST
Subject: [alt-beam] Re: delete
delete
12808 Thu, 30 Mar 2000 08:01:02 -0500 Re: glider. A blimp is easier :-) Justin
> >This maybe a 'cool' idea, but its also a bad idea.
> >An automated R/C aircraft falls under the FAA rules if operating out of
the
> >pilot's' sight.
>
> Methinks that having the necessary RC gear onboard but choosing not to
> use probably gets around this, because this means the plane is never out
> of your control - even if you're not controlling it :-)
>
> Personally, I'd be more interested in making a miniature helium blimp
> that navigates around the house, and it's a hell of a lot simpler to
> build (you could even use an off-the-shelf photopopper circuit if you
> really wanted to). "TPM" motors with tiny propellers put out a lot of
> thrust for their minuscule weight. (Unfortunately not _more_ thrust than
> their weight though, as far as I can tell...)
>
> Problem - actual balloons are no good for lift - they deflate after a
> while. The expelling pressure the rubber exerts on the gas is obviously
> a big factor, but as well as escaping through the knot, I wonder if the
> rubber itself might not be completely helium-proof. The first problem
> (rubber trying to expel the gas) is easily solved by using a slack
> bladder (reminds me of a Blackadder joke...), but if helium can actually
> pass through rubber, what else can it pass through - what material
> should we use that is helium proof?
> (I don't want to have to refill the thing will helium every few weeks).
>
> Waaay down the track, an outdoors unit that uses the sun to extract
> hydrogen from rainwater could act as a refilling station for any leaks,
> but that's not really plausible right now, and hydrogen gas has some
> er... drawbacks... :-)
>
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