RE: Slow planes was: Battle blimps

Another possibility is some type of "altitude bladder".  Since the lift
is generated by helium displacing an equivalent volume of air, if you
had a large center bladder that could be contracted or expanded as
needed, you could shift the amount of air displaced without having to
release gas.  You would just compress the helium in the bladder until it
was of high enough density to stop you from rising.

Perhaps modern/futuristic blimps will have fabric made from fullerene
strands or spider silk which might allow really high tensile strengths
but retain flexibility and allow you to withstand higher helium
pressures than is currently possible.

--Binhan

> -----Original Message-----
> From: Allan Goodall [mailto:agoodall@att.net]
> Sent: Friday, April 19, 2002 1:48 PM
> To: gzg-l@csua.berkeley.edu
> Subject: Re: Slow planes was: Battle blimps
> 
> 
> On Fri, 19 Apr 2002 13:56:57 -0400, Ryan M Gill 
> <rmgill@mindspring.com> wrote:
> 
> >The more advanced Zeps had a special pressure valve that vented when 
> >the airship went above "pressure altitude". The American made 
> >Airships (The Akron and Macon) were fitted with condensors that 
> >recovered water vapor from the engines in order to replenish ballast 
> >and reduce the loss of ballast weight as fuel was consumed.
> 
> They still had problems, though, even with the pressure 
> valve. A number of
> atmospheric effects could send them upwards, where they had 
> to vent gas, only
> to have the effect disappear and the ship sink without enough gas to
> stabilize. They were particularly tricky things to fly. The 
> idea posted here
> that they could stay in the air for weeks is perhaps a bit 
> optimistic. On the
> other hand, with "gas refueling" airships and such, maybe it 
> could work.
> 
> I'm not sure a condensor would be much good in the 80,000 to 
> 100,000 feet
> range, though. Not a whole lot of moisture up there...
> 
> 
> Allan Goodall 		 agoodall@hyperbear.com
> http://www.hyperbear.com
> 
> "At long last, the earthy soil of the typical, 
> unimaginable mortician was revealed!" 
>  - from the Random H.P. Lovecraft Story Generator