From: camelsho@sportster.ksu.ksu.edu (   James A Seymour)
Newsgroups: sci.energy
Subject: Popular Science Fly Wheel Article
Date: 21 Dec 1992 01:51:19 -0600
Organization: Kansas State University
Distribution: world
NNTP-Posting-Host: sportster.ksu.ksu.edu

I'm not sure if this is the article which started the
whole fly wheel discussion.  However, its probably
the one most widely read.

Just so we are not talking apples and oranges, I am
posting the text of that article with out permission.
This comes from the January '93 issue of Popular 
Science, page 27.

There is also a drawing that helps explain the text.  If you
are at all interested, I suggest you locate a copy of the
issue and to see the diagram.


******************** Article Follows *****************************
                   
                       FLYWHEEL POWER

A Seattle company claims its flywheel battery is the "missing link"
that will enable electric cars to match the performance of vehicles
powered by internalcombustion engines.

The American Flywheel Systems (AFS) battery contains a pair of 
counter-rotating "rim wheels," suspended by magnetic bearings in a
vacuum housing.  The rim of each wheel is made from a high-tensile-
strength fiber, such as Kevlar.  Spoke tubes containg magnets connect
the rims to lightweight hubs.  An electric charge sets the wheels in
motion, and they can perform work as they continue spinning--like a 
potter's wheel.

The idea of using a flywheel to store energy is not new, but designing
a device that works efficciently and safely has jproved difficult.  To
power a car, a flywheel battery must be capable of rotating at 150,000-
200,000 rpm.  If the flywheel is a metal disc, it could break into 
shrapnel at that speed.  And if it is a spoked wheel, the rim pulls
away from the hub at high rpms.

AFS claims to have solved some of these provlems.  For example, the
new battery's spoke-tube assembly allows the flywheel rim to expand
without separating from the hub.  And when the rim is spun so fast 
that it fails, the Kevlar fibers simply turn into "cotten candy,"
says Edward W. Furia, chairman and chief executive officer of AFS.

Furia says his new battery could make GM's proposed Impact electric
car go as far as 600 miles on an overnight charge.  The Impact now
runs on 32 lead-acid batteries and has a range of about 80 miles.
Replacing the lead-acid batteries with 20 flywheel batteries, each
weighting 30 pounds, would also improve the car's acceleration, 
according to Furia.  He says flywheel batteries have a high power
density--they can give up energy quickly.

"It's very important to overcome the perception of electric cars as
glorified golf carts of greenmobiles," says Furia.  "Electric cars
should be capable of dazzling performance."

The flywheel battery would last about ten times longer than a lead-
acid basttery--which must be replaced after 25,000 miles.  And since
it uses no chemicals, it wouldn't create corrowsion or disposal
problems.

For now, the flywheel battery exists only as a computer simulation.  
It will take a bout two years to build a protype for a car, Furia
estimates.  The battery could also be aused to store electricty
generated by solar or wind power.--Dawn Stover

*****************************  End Article *****************************

james seymour/camel/camelsho@matt.ksu.ksu.edu