From: Ad 

http://www.gizmag.com/go/7046/

Tell me this is just "blue sky....."

"With all the effort we are witnessing in developing environmentally
progressive technologies for automotive applications, it’s great to see
that Boeing researchers and industry partners throughout Europe are
planning to conduct experimental flight tests this year of a manned
airplane powered only by a fuel cell and lightweight batteries. The systems
integration phase of the Boeing Research and Technology Europe (BR&TE)
Fuel Cell Demonstrator Airplane research project was completed recently and
thorough systems integration testing is now under way in preparation for
upcoming ground and flight testing. The Boeing demonstrator uses a Proton
Exchange Membrane (PEM) fuel cell/lithium-ion battery hybrid system to
power an electric motor, which is coupled to a conventional propeller. The
fuel cell provides all power for the cruise phase of flight. During takeoff
and climb, the flight segment that requires the most power, the system
draws on lightweight lithium-ion batteries."


Looks like Long Range quiet drone tech is being civilianized.

For drones it's a combo of the above + solarpanels etc. so as to give a
very long period of endurance possibly at very high altitudes (neither
solar cells nor batteries nor fuel cells require atmospheric
oxygen.....(e.g. the new "conventional" very quiet submarines).


Fuel cell at night & to top up the batteries if required, solar panels
& simple good gliding for the rest.

Adam

--- BBBS/NT v4.01 Flag-5