What is the best lifting gas for an airship?

Technical discussions regarding LTA-technology.

What is the best lifting gas for an airship?

Hydrogen
10
34%
Helium
11
38%
Methane
0
No votes
Hot Air
0
No votes
A combination of one/more of the above
8
28%
Other
0
No votes
 
Total votes: 29

turtleairships
Posts: 138
Joined: Sun Mar 06, 2016 10:15 pm
Gender: None specified
Contact:

Re: What is the best lifting gas for an airship?

Postby turtleairships » Mon Sep 05, 2016 1:42 am

Alas, no diagrams available at the moment. a very few crude, not quite accurate illustrations. Here is one: Image

Yes to the twin wall.......however, only outside to be CF, inside ideally to be "continuous ceramic fiber reinforced aluminum".....with an aerogel-like matrix between. Interior framing is necessary, but minimal, as the geodesic construction of the hull provides for a sturdy framework, something akin to a metal standing seam joinery.....

"ground impact" GROUND IMPACT!? why, the very idea! what, we're Airlander???
heh heh!

No.....I certainly understand your point.
and so........actually, Turtle Airship's primary landing choice is into water (three longish cabin/gondola hull portions act as a trimaran boat )
Terra Firma as well, of course............there is some flexibility to those same three hull portions that will serve to absorb shock......

using methane of course, will have some negative connotations, since it is considered to be the worst "greenhouse" gas. On the other hand, we can simply point out that it would vent naturally into the atmosphere anyway, so we are just gaining some usefulness out of it beforehand....

pyronaught
Posts: 123
Joined: Thu Jul 07, 2016 2:04 am
Gender: Male
Flag: United States of America

Re: What is the best lifting gas for an airship?

Postby pyronaught » Mon Sep 05, 2016 5:27 am

I wouldn't call medical use of helium wasteful. In the grand scheme of things, saving lives is more important than floating around in airships. The industrial uses are probably pretty important too, and both groups would likely consider airships the more wasteful use of helium due to the massive quantities consumed for what currently is nothing more than marketing campaigns. Personally I think party balloons are the main waste of helium. Hanging them from the ceiling works just as well as floating them with helium and looks exactly the same.

yama
Posts: 31
Joined: Wed Aug 31, 2016 7:47 pm
Gender: None specified

Re: What is the best lifting gas for an airship?

Postby yama » Mon Sep 05, 2016 9:02 am

I wonder if the dangers of hydrogen could be mitigated somewhat by using mix of hydrogen and helium? I see this is a question asked before: I found a mention that under US law, "Section 14, Transportation, the
sheet states mixtures of 8.7% or less hydrogen in helium may be shipped as non-flammable gas."
8% hydrogen mix with helium would be probably not worth the hassle. In Zeppelin NT-sized ship it would produce just some 50kg more lift and not much, if any, cost saving. If it could be demonstrated that richer mix - say 30% hydrogen - would produce major improvement in safety, it might be worth consideration? (even though such a mix would probably still be flammable, just not as violently. It would be interesting to see some practical experiments).

For party balloons, maybe they could use 50-50 mix of helium and nitrogen? That would cut helium wastage by half AND make the balloon gas cheaper as well. It's not like party balloons need maximum lift.
Ah, again this was not a new idea, it seems that "party balloon helium" is nowadays often 20% air for exactly that.

meme
Posts: 8
Joined: Fri Sep 02, 2016 8:55 pm
Gender: None specified

Re: What is the best lifting gas for an airship?

Postby meme » Mon Sep 05, 2016 1:51 pm

pyronaught wrote:I wouldn't call medical use of helium wasteful. In the grand scheme of things, saving lives is more important than floating around in airships. The industrial uses are probably pretty important too, and both groups would likely consider airships the more wasteful use of helium due to the massive quantities consumed for what currently is nothing more than marketing campaigns. Personally I think party balloons are the main waste of helium. Hanging them from the ceiling works just as well as floating them with helium and looks exactly the same.


The problem is not usage of helium, it's the lack of recapture. An MRI operator makes regular purchases of liquid helium for cooling and just vents the boiled off helium into the atmosphere. Some have begun installing recapture systems, but it's a minority at present.

I really feel that people blaming lifting purposes are missing the point, because lifting purpose simply don't consume that much helium. And modern fabrics have literally several orders of magnitude less permeation than old ones, and new techniques help reduce or eliminate the need for venting. Airships are a highly visible user of helium, but not a major one.

Re, party ballons: Indeed they are a waste - but then again, what kids toys (and let's face it, party balloons are kids toys) aren't a total waste of resources? And again, that's still a minor use of helium compared to industry and medicine. Party balloons and lighter than air vehicles combined are something like 11% of global helium consumption.

yama
Posts: 31
Joined: Wed Aug 31, 2016 7:47 pm
Gender: None specified

Re: What is the best lifting gas for an airship?

Postby yama » Tue Sep 06, 2016 8:14 am

Yes, according to USGS: "Estimated 2014 domestic consumption of helium was 34 million cubic meters (1.2 billion cubic feet) and was used for cryogenic applications, 32%; for pressurizing and purging, 18%; for controlled atmospheres, 18%; for welding cover gas, 13%; leak detection, 4%; breathing mixtures, 2%; and other, 13%."

marts
Posts: 11
Joined: Mon Apr 04, 2016 12:25 pm
Gender: None specified

Re: What is the best lifting gas for an airship?

Postby marts » Tue Sep 06, 2016 9:49 am

Helium for party balloons is the lower purity gas that may go to waste if they did not sell it during purification processes. The income generated keeps the costs down for other helium users. Info from former UK helium supply manager.

pyronaught
Posts: 123
Joined: Thu Jul 07, 2016 2:04 am
Gender: Male
Flag: United States of America

Re: What is the best lifting gas for an airship?

Postby pyronaught » Tue Sep 06, 2016 10:33 pm

The party balloon helium is the same stuff you get from industrial gas suppliers for a welding shield, which would then be the same thing that everyone fills their RC blimps with. Thus I'm guessing it is the same grade used to fill full size blimps, as paying medical grade prices just to get some tiny bit of increased purity would make something that is already expensive even more expensive for little gain.

yama
Posts: 31
Joined: Wed Aug 31, 2016 7:47 pm
Gender: None specified

Re: What is the best lifting gas for an airship?

Postby yama » Thu Sep 08, 2016 9:57 am

yama wrote:I wonder if the dangers of hydrogen could be mitigated somewhat by using mix of hydrogen and helium? I see this is a question asked before: I found a mention that under US law, "Section 14, Transportation, the
sheet states mixtures of 8.7% or less hydrogen in helium may be shipped as non-flammable gas."
8% hydrogen mix with helium would be probably not worth the hassle. In Zeppelin NT-sized ship it would produce just some 50kg more lift and not much, if any, cost saving. If it could be demonstrated that richer mix - say 30% hydrogen - would produce major improvement in safety, it might be worth consideration? It would be interesting to see some practical experiments).


Continuing on the point, in this video someone tries it out by burning out bags containing hydrogen, helium and presumably 50-50 mix of hydrogen-helium (or thereabouts, the setup is not too scientific and seems slightly hazardous). Predictably, hydrogen bag burns out violently, helium bag slowly, and mixed gas burns readily but somewhat less explosively than pure hydrogen. So if this video is a guideline, using 50-50 mixture would probably lessen the risk of ignition somewhat, and reduce the explosivity of fire if it does break out, but basically one would have to take all the same precautions as using pure hydrogen.

Crunching some numbers, mixing just little bit of hydrogen into helium might be actually worth it for a very large operator. I Don't know helium's retail cost but according to USGS, "estimated price of Grade A helium in private industry is $7.21 per cubic meter". So going by that number, inflating a 50 000m^3 airship (as envisioned in Zeppelin Euro Tour) would cost about $360 000. Saw a mention that hydrogen costs about 1/10th, so mixing in 8% hydrogen would save roughly $25 000 per fill. Also, it would produce ~350kg more lift. This would allow maybe two extra passengers carried. This all might seem insignifant, but those two extra passengers would be pure profit and that we're talking about an enterprise based on carrying maybe 40-50 passengers per flight, in an industry where profit margins are wafer-thin. This all IF it was shown that such a lean mix is for practical purposes no more dangerous than pure helium.

Mack
Posts: 27
Joined: Sat Apr 02, 2016 10:51 am
Gender: None specified

Re: What is the best lifting gas for an airship?

Postby Mack » Fri Sep 09, 2016 3:07 pm

The only LTA-craft I'd fly with hydrogen is a gas balloon, on the condition that I can carry a parachute.

The super large amounts of hydrogen that would be needed in large airships is too scary for me. And truth be told, I prefer no airships over airships filled with hydrogen. Another Hindenburg-type disaster is the last thing the world and the industry needs to see.

User avatar
flyhigh
Posts: 130
Joined: Fri Mar 25, 2016 10:04 pm
Gender: None specified
Flag: United States of America

Re: What is the best lifting gas for an airship?

Postby flyhigh » Sun Sep 11, 2016 9:55 pm

@Mack I think you make a realistic point. I believe most here don't think that some large airship currently in existence or being designed is going to use hydrogen. The public perception for such an endeavor is very negative, and the need for airships is too low compared to 100 years ago.

Making hydrogen more accepted for LTA would have to come gradually.

For large rigids there would need to be some large Airship Association full of enthusiasts (some with big money) that has lobbying powers. But I am skeptical if this could ever come...interest isn't very high.

In the mean time, it could start out with expanding the sport of gas-ballooning with hydrogen. Get in touch with the Hot air balloon crowd and show them the benefits of gasflights. Then after a few years or decades of successful gasballoon flights, the perception of using hydrogen would change positively. If gasballooning could become as popular as hot air ballooning, we'd be a long way. Than the road to using it in smaller blimps would open naturally, or of course blimps with an outer helium and inner hydrogen cell as mentioned earlier. This could at least make blimps more prominent, cheaper to run and maybe open up the a sport-blimping market for rich folk, just as there are sport planes and whatnot

I too am skeptical about large passenger rigids using hydrogen again, I feel there's just so little demand for it, it all depends on the demand of the public. Because of that I am more interested in blimps aka smaller non-rigids. I hope that I can contribute to this field within 10 years, when I've accumulated enough capital and have more free time. It'll probably be a thermal airship...
blimps don't crash, they sink.
~don't tread on me~


Return to “Technical Aspects”

Who is online

Users browsing this forum: No registered users and 2 guests