On Fri, 24 May 2013 15:18:35 +1200, george152 wrote:

A cross country at 45 knots ?????
That's a toy!

Agreed. But a fun, unlicensed toy none the less. Add transponder, and it
could get me from a remote strip atop Point Conception to my airport-car at
KSBA to facilitate grocery shopping. Call me a dreamer ...

Battery technology is constantly improving:

http://www.gizmag.com/researchers-increase-lifespan-lis-batteries/26911/:
Though more powerful and less expensive to produce than the more widely used
lithium-ion batteries, lithium-sulfur batteries have typically sported a
comparatively poor lifespan. However, the Dresden-based researchers have
successfully developed a new design that increases the charge cycles of
lithium-sulfur batteries by a factor of seven.

“During previous tests, the batteries scarcely crossed the 200-cycle mark,”
said Dr. Holger Althues, head of the Chemical Surface Technology group at IWS.
"By means of a special combination of anode and cathode material, we have now
managed to extend the lifespan of lithium-sulfur button cells to 1,400 cycles."

IWS researchers expect to refine the lithium-sulfur batteries to the point
where they reach an energy density of up to 600 watt-hours/kilogram (Wh/kg).
This would beat the lithium-ion density record of 400 Wh/kg claimed last year
by Envia, and more than double that of Li-ion batteries currently in use.

"Lithium-sulfur technology might even make electric flying a realistic
possibility,” said Althues. “Although such progress is still a long way off.”