In article 41b7993d-0921-4844-a040-b30d717782d6
@g20g2000prg.googlegroups.com, says...

On Nov 8, 1:10*pm, Jeff Findley wrote:

That said, there are still very real risks of using H2 as a lifting
gas. *
Great care has to be taken to insure that H2 doesn't escape into
enclosed areas of an air ship which are filled with air, because a
flammable, or even explosive, air/H2 mixture can be created in such a
situation. *H2 leaks into the atmosphere are far less of a fire risk.

Note that H2 leaks in the aft section of the space shuttle have been an
issue on several shuttle missions. *When such leaks are detected and are
above a certain level, the launch is scrubbed until the leak is fixed. *


In a typical terrestrial blimp application, H2 only leaks upwards.
When's the last time any cabins or equipment was located directly
along side or much less above the H2 cells?

Who said anything about cabins or equipment?

Interactive Hindenburg diagram:
http://www.pbs.org/wnet/secrets/html/e3-diagram.html

In the above, please note the areas which are inside the middle of the
H2 cells. Such areas could become filled with a hydrogen/air mixture if
one of the hydrogen gas cells leaked or ruptured.

It's my feeling that there just weren't enough Hindenburg like air ships
built and flown to find all of the possible failure modes involving
hydrogen. As a thought experiment: In an alternate history where the
shuttle program ended after the Challenger disaster, the failure mode
which led to the loss of Columbia would never have been found.

Jeff
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