I was just wondering....is it possible to have a UAV to be launched at altitude and then find thermals to stay up all day (and maybe night)? I don't mean for UCAVs or for UAVs required to move all that much...more for ones that would be for surveillence over a fixed area (of which it could vary around to keep in thermals as necessary).

Also when was the last time a glider was used by an air-force for offensive operations? Are there any uses for them in the modern combat field?

Or the Blimp Lockheed is going to build for Homeland Security which can stay up for months at a time in the same position. It would carry surveillance equipment and chemical detection equipment for the Department of Homeland Security. It is technically an UAV.

Acually SHADOW if I remember right they kept crashing so they cancelled that program, the had trouble keeping themselves up let alone pounds and pounds of equiptment.

Dont forget helios, in essence a glider with electric motors and solar cells. Climbed to like 90,000 feet in one test and could stay aloft for days on end.

Originally posted by FredT
Dont forget helios, in essence a glider with electric motors and solar cells. Climbed to like 90,000 feet in one test and could stay aloft for days on end.

But when does a motor glider like that become a powered plane. I argue that the helios is a plane as the enigines stay on continuously don't they?

Originally posted by Infidellic
But when does a motor glider like that become a powered plane. I argue that the helios is a plane as the enigines stay on continuously don't they?

At night, the plane would loose alot of altitude because of the lack of solar power and the limited capacity of the batteries. Your right its not a glider, but fairly close, the engines are pretty weak and it is in essence a giant solar panel.

[edit on 9-8-2004 by FredT]

I could definitely see a glider being made, actually more of a sailplane since gliders have much smaller wings and don't take advantage of thermals. Check out the model airplane magazines. Modelers have been making amazing sailplanes for decades.