🚀 go-pugleaf

In article <Bz6nuM.LCo@acsu.buffalo.edu>, v064mb9k@ubvmsd.cc.buffalo.edu 
(NEIL GANDLER) writes:
>  I just have finished reading the latest Popular Science issue. Jan 93.
> On p. 27 they discuss flywheel power as a possible energy source for 
> future Ev's. Claimed advantges are a cruising rnage of over 600 miles
> on an overnight charge on GM's Impact. With a battery weight of only
> 600 pounds and a life of 25,000 miles and with no chemical waste when
> disposed this new power source could revolutionise the
> EV industry. Why is this technology not being looked into more. What
> are the dissadvantages. What is this technology exactly. How is
> mechanical energy stored in such great amounts. 

It isn't exactly "new" -- PS had a cover story on flywheel-based EVs something
like 20 or 30 years ago.  At that time there was a small fleet of
flywheel-driven streetcars in, I believe, Denmark. These did not use a
high-tech flywheel and could run for only ten minutes or so away from the power
source -- but that was sufficient to allow them to leave the overhead power
lines for a block or two. 

To be usable for an electric vehicle, you need a massy, large-diameter flywheel
that spins at phenomenal speeds.  It is made with high-tech materials (carbon
fibers, that sort of thing) so that it won't tear itself apart.  It must be
spun in a vacuum chamber or else a lot of the stored energy goes to heating the
air.  It must be Floated on near-frictionless bearings, such as magnetic
bearings, and coupling to the outside is via a magnetic clutch (ie the flywheel
shaft does not extend outside the enclosure).  

All of this is easy to dream up but a bit hard to actually build, especially in
production quantities. 

The flywheel must be arranged with a vertical axis so that gyroscopic effects
don't make it impossible to turn the car.  Still, you need to worry about these
effects whenever the car enters a sharply-banked road or freeway ramp.  

Popular Science publishes an awful lot of "gee-whiz" stuff, with the 
implication that these things are just around the corner.  It often isn't so,
and I don't think it's so with the flywheel-powered EV. 

	--- Jamie Hanrahan, Kernel Mode Consulting, San Diego CA
Internet:  jeh@cmkrnl.com, hanrahan@eisner.decus.org, or jeh@crash.cts.com
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