🚀 go-pugleaf

In article <BzE2oz.I4H@ns1.nodak.edu>, csmith@plains.NoDak.edu (Carl Smith) writes:
>I am not going to argue the above point, but consider this.  If you are
>going to measure danger by the amount of stored energy, then which is
>more dangerous when it explodes?  A flywheel that has enough energy to 
>move a car 100 miles at freeway speeds, or a tank of gasoline with enough 
>energy to move a car at greater-than-highway speeds for 300 miles?

The tank of gasoline, of course.  I certainly wouldn't want to be standing
anywhere near a fuel/air bomb using ~8 gallons of gasoline if it went off.  Of
course, should the gasoline ignite after a car's been in an accident, you're
highly unlikely to have much fuel-air mixture that's at explosive proportions. 
That 8 gallons of gasoline will take quite some time to burn off.  The same
can't be said for your flywheel.

>>Unless you wrap the flywheel in a massive enough container that it can absorb
>>all that energy without vaporizing, you're going to have an explosion.
>
>Why bother, we don't wrap our gas tanks in a container that would contain
>their explosion?

There's no way you're going to burn a full tank of gasoline in a fraction of a
second.  The difference in the power of the two explosions in question will be
orders of magnitude.

>The point I am trying to make is that flywheels may be dangerous, but driving
>around with 20 gallons of gasoline strapped to the bottom of your car in a
>thin sheet metal container is A LOT MORE dangerous.

Depends on which is more likely to fail.  If the flywheel fails, you're going
to have a lot more powerful failure mode than if the fuel tank fails.

>But we consider that 
>risk as acceptable considering the convenience that we get from our cars.
>So, why the worry about deriving the same convenience from a lesser danger?
>Because people are not used to doing it every day...

Show me a flywheel which, if it fails, will take on the order of half an hour
to spin down, and I'll grant that your claim has some merit.  However, if your
flywheel spins down in a fraction of a second, it's going to be a lot worse
than a fuel tank rupturing and igniting, unless you've got something that can
absorb all that energy.
--------------------------------------------------------------------------------
Carl J Lydick | INTERnet: CARL@SOL1.GPS.CALTECH.EDU | NSI/HEPnet: SOL1::CARL

Disclaimer:  Hey, I understand VAXen and VMS.  That's what I get paid for.  My
understanding of astronomy is purely at the amateur level (or below).  So
unless what I'm saying is directly related to VAX/VMS, don't hold me or my
organization responsible for it.  If it IS related to VAX/VMS, you can try to
hold me responsible for it, but my organization had nothing to do with it.