SoLong Solar-Electric UAV 48 hour flight

On 19 Oct 2005 20:47:6 -0500, "Ash Wyllie" wrote in
::

Larry Dighera opined

I ran across this flight earlier. there is less here than meets the eye. During
the day the pilots, all of whom are experienced RC glider pilots, used thermals
so all the solar power collected could be used to charge the batteries for the
night time.

Where did you get that bit of information?

If the aircraft had had to circle over the same spot, the flight would have
been much shorter.

Agreed, if atmospheric convective lift was indeed used to sustain the
aircraft during daylight hours. While it's still solar power, but not
photovoltaic, it would not be of practical use for sustaining the
aircraft indefinitely.

Solar cell efficiency and battery storage density need to at least double before
true stay aloft forever is going to happen.

How did you calculate that factor?

Triple-Junction Gallium Arsenide solar cells with efficiencies of
about 31% under terrestrial conditions are the most efficient of which
I am awa

http://www.boeing.com/news/releases/...r_030725s.html

HIGH-EFFICIENCY SOLAR CELLS
July 25, 2003
News Release
A Spectrolab, Inc. associate places wafers on platters for epitaxial
growth. The wafers are then fabricated into solar cells that will be
capable of an unprecedented 36.9 percent efficiency in converting
sunlight to energy when exposed to concentrated sunlight. Spectrolab,
a Boeing subsidiary, uses these state-of-the-art photovoltaic solar
cells in concentrator modules of various sizes and power-generating
capabilities. Several modules are already being tested throughout the
world by photovoltaic concentrator system manufacturers. These
Spectrolab products could be part of terrestrial systems that
dramatically reduce the cost of generating electricity from solar
energy.

Contact:
Spectrolab, Inc.
Public Relations Department
P.O. Box 92919 (S10/S323)
Los Angeles, CA 90009
Public Relations (310) 364-6363
www.boeing.com/satellite
http://www.spectrolab.com/

Triple-Junction with a minimum average efficiency of 26.5%) developed
and manufactured at Spectrolab. Ultra-Triple-Junction solar cells,
with a minimum average efficiency of 28.3%, are now in production

http://www.spectrolab.com/stores/
Spectrolab has a variety of solar cells in inventory and available in
limited quantities. Some of these solar cells are rejects from the
production line, others are surplus material from space programs. All
are limited to small batches and sold on a first-come first-serve
basis.

Improved Triple-Junction Gallium Arsenide with efficiencies of about
26.8% (AM0) or about 31% under terrestrial conditions.


Some of these solar cells are in excellent condition while others are
functionally limited to a certain type of application. Call Mike
Kalachian at (818) 898-7540 or send an e-mail to: Mike Kalachian to
inquire about what is currently available.


If you are ready to place an order, please download the appropriate
form, fill it out appropriately and fax it to Mr. Kalachian's
attention at: (818) 361-5102

The era of silent, zero emission flight is upon us. Never run out of
fuel again.


http://www.acpropulsion.com/whats_new.htm
AC Propulsion SoLong UAV Flies for 48 Hours on Sunlight
Two Nights Aloft Opens New Era of Sustainable Flight
[...]