Airship-to-Orbit?

Pete Schaefer wrote:
"Wright1902Glider" wrote in message
...

What happens to the gas bag once it makes orbit? Am I correct in assuming

that

there will be a serious pressure differential between the interior and

exterior

of the bag? I'm thinking "World's Largest Baloon Goes POP!" ?????


Maybe they're going to stress the skin so that it pops open at the back end,
with the escaping gas supplying thrust.

Hey, good idea!

I am wondering about possibly using Hydrogen. At the extreme altitudes
considered, I'd think the flammability issue would be much less. And
Hydrogen is significantly more bouyant than Helium. Maybe a mix of the two?

The hydrogen issue is more of a psychological one. It's pretty well
understood now that the Hindenburg thing was more a problem of skin
materials that became extremely flamable when heated (chemical change).
Hydrogen fires generally blow themselves out. With a different skin, maybe
only one or two cells on the Hindenburg would have blown out from the
lightning strike.

Still, anytime anyone mentions using hydrogen as a lifting gas....."......OH
NO!!! NOT ANOTHER HINDENBURG!"

And you're right. What little concern you might have about flamability would
pretty much go away, unless you were using regular air for ballast and there
was potential for mixing (which would probably mostly be gone by the time
you got up pretty high).

"nafod40" wrote in message
...
I am wondering about possibly using Hydrogen. At the extreme altitudes
considered, I'd think the flammability issue would be much less. And
Hydrogen is significantly more bouyant than Helium. Maybe a mix of the
two?

I would think hydrogen would be an obvious choice. Helium molecules are so darn
small that they leak out of practically anything. That is why the coated mylar
party balloons are used instead of latex.

Hydrogen likes to be H2 which is huge compard to a single helium, and lighter
yet stronger materials can be used to hold it.

-- Charlie Springer

"Regnirps" wrote in message
...
I would think hydrogen would be an obvious choice. Helium molecules are so
darn
small that they leak out of practically anything. That is why the coated
mylar
party balloons are used instead of latex.

I have never noticed that helium filled latex balloons lose buoyancy any
faster than the Mylar ones. I thought Mylar was used because it is bright
and shiny. I have also heard that birds are less likely to eat it and die,
which probably ranks right up there with urban legends about wedding rice
and birds. Back in the old days (when I was a child) I used to sell balloons
to raise money for Rotary and the local rodeo. No such thing as Mylar
balloons then, but they were filled with helium. The balloons would hold
their helium for a week or more. I also recall latex weather balloons filled
with helium. Although I personally launched literally thousands of toy
balloons filled with helium, I never heard of a bird being killed by one. I
have seen toy helium filled balloons at 11,000 feet.

When we lived in the Philippines in the 70's they still sold balloons filled
with hydrogen, which has been banned in the US because of its flammability.
Let one of these toys near a lit cigarette and you could have one badly
burned kid.

"C J Campbell"

I have never noticed that helium filled latex balloons lose buoyancy any
faster than the Mylar ones.

A regular ballon is usually limp in less than 24 hours and useless shortly
after that. The Maylars are good for about a week I think. I either case, I
wonder how much is escaping through the knot or filler adhesive?

-- Charlie Sprinher

A regular ballon is usually limp in less than 24 hours and useless shortly
after that. The Maylars are good for about a week I think.

I've had a 12" (30cm) Mylar balloon hold its lift for over a month.

I either case, I
wonder how much is escaping through the knot or filler adhesive?

Sometimes a plastic plug is used in He-filled rubber balloons. Might that work
longer?

(G EddieA95) wrote:

Sometimes a plastic plug is used in He-filled rubber balloons. Might that
work
longer?

It might help a little, but the helium is diffusing right through the rubber.
The stuff is notorious. Many a physics graduate student has spent years chasing
down helium leaks in high vacuum and cryogenic equipment.

-- Charlie Springer