From: carl@SOL1.GPS.CALTECH.EDU (Carl J Lydick)
Newsgroups: sci.electronics,sci.energy,rec.autos.tech
Subject: Re: Flywheel batteries as EV power source
Date: 17 Dec 1992 18:37:46 GMT
Organization: HST Wide Field/Planetary Camera
Distribution: world
Reply-To: carl@SOL1.GPS.CALTECH.EDU
NNTP-Posting-Host: sol1.gps.caltech.edu

In article <1992Dec17.170002.28389@u.washington.edu>, basiji@stein.u.washington.edu (David Basiji) writes:
=>You're saying, then, that you couldn't melt that container with a blowtorch and
=>on the order of a gallon of gasoline?  And that you STILL couldn't melt it if
=>you managed to apply all that heat in the course of a fraction of a second? 
=>Sounds like pretty impressive stuff to me.
=
=I haven't been following this thread for very long, so perhaps I should
=state my assumptions.  I'm assuming we're talking about a vehicle with
=a relatively low-power/high duty cycle motor that spins a flywheel to
=very high speeds.

Ah.  That accounts for a lot.  Perhaps you'd care to review the title of the
thread: "Flywheel batteries as EV power source."  That's why I was talking
about enough energy to travel for ~100 miles at freeway speeds.  Now, if you
simply want to use the flywheel for load averaging, then we're talking about a
LOT less energy stored in the flywheel.  In that application, I'd agree with
you that the dangers of a catastrophic failure of the flywheel would be quite
acceptable.

=It is the flywheel which provides the motive force
=for the vehicle via some clutch and gearbox or torque converter.

The idea in this thread was that the flywheel is part of a generator which
provides electrical power to the vehicle's electric motor.  That's what the
"EV" stands for in the title of the thread, and why it refers to the flywheel
as a "battery."

=The housing I've proposed is suited to these conditions.  Since we're 
=encouraging collisions between particles by containing them, much of their
=kinetic energy will be dissipated in collision-induced fractures of the 
=flywheel material. Heat is generated in the housing only in irrecoverable
=deformations of the flywheel materials and the housing itself, not fractures
=or elastic deformations. Assuming the flywheel is brittle, there will
=be fractures but not much elastic deformation.

I'm afraid you've forgotten the law of conservation of energy again.  I ask
again:  IF THE ENERGY THAT'S BEING DUMPED DOESN'T END UP AS HEAT, WHERE'S IT
GOING?  HOW'S IT BEING TRANSFERRED OUT OF THE SYSTEM?

=With proper engineering of the flywheel
=to shatter into uniformly-sized pieces (for maximum energy xfer in collision)
=and an appropriate weave or composite of Kevlar in the housing, it seems
=that it's within shooting range (pardon the pun) to develop a system where
=there's enough energy loss via particle collision and fracture that the
=heat generated in the housing materials will be manageable. 

Again you prattle of "energy loss."  WHERE IS THIS ENERGY BEING "LOST" TO?
It doesn't just go away because you find it inconvenient.  And the remnants of
the flywheel don't just keep orbiting the place where the shaft used to be.  So
where did all the kinetic energy go?
--------------------------------------------------------------------------------
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.