The "Whirl": More Efficient Rotary Craft?

An interesting concept. Large chord and relatively slow turning wings
(rotor blades) may work, but it's maximum forward speed is probably very
slow.

Perhaps an unmanned modern airship, particularly if it is filled with
hydrogen, might do just as good. In fact, in a no-wind or low-wind situation
the airship should offer a better loiter time.


"sanman" wrote in message
om...
Here's something I was reading:

http://www.newscientist.com/news/news.jsp?id=ns99996380


So beyond the mere claim of being more efficient, why would it actually be
so?

The claim of hovering for 4 days is quite a jump, when compared to Global
Hawk.

Is this even vaguely realistic?