I read about this about 13 years ago in Discover: http://www.mega.nu/ampp/bitterly.html http://www.mega.nu/ampp/bitterly.html Seemed like a fantastic idea at

I read about this about 13 years ago in Discover: http://www.mega.nu/ampp/bitterly.html http://www.mega.nu/ampp/bitterly.html Seemed like a fantastic idea at the time, but the problem then was that the wheel would explode at high speeds. Apparently these are very challenging to manufacture.