I just heard about a new airship today on PBS

[Guest]

I thought this sounded pretty cool.

http://www.thestory.org/stories/2013-05/flying-submarine

[Kerbface]

It does sound cool, but I still wish they would make one with hydrogen. From what I can tell, there's no real disadvantage and it has much more lifting power, plus helium is rare and costly. Apparently nobody wants to use hydrogen because of the Hindenberg, though maybe there's another reason I haven't heard of.

And compressed lifting gas to allow for carrying different cargo... they didn't do that before? I was under the impression that that was how airships controlled their height.

[Phoenix Aerospace]

It does sound cool, but I still wish they would make one with hydrogen. From what I can tell, there's no real disadvantage and it has much more lifting power, plus helium is rare and costly. Apparently nobody wants to use hydrogen because of the Hindenberg, though maybe there's another reason I haven't heard of.

And compressed lifting gas to allow for carrying different cargo... they didn't do that before? I was under the impression that that was how airships controlled their height.

I agree with you totally. Hydrogen is perfectly innocuous so long as it doesn't come into contact with air, and even if it does, it requires a precise mixture in order to explode, as well as a relatively powerful ignition source. We use hydrogen for our High Altidude Balloon flights, and we have not yet had one single incident with the gas.

Also, airships use air-filled bladders as ballast in order to control height. Pump more air in = More weight = Less lift. Though I guess they would compress the gas cells, and that that would somewhat impact lift...

[Guest]

From what I heard on The Story today, this is a recent development. They said something about using a bladder to draw in air as the helium is being compressed. Not really sure, I would have to listen again. Anyway, the end result being no wasted helium. I don't think this has been tried before on this scale. Plans for a ship to lift 250 tons are in the works. Here is the link for the report : http://www.thestory.org/mediaplaylist/popup

[Phoenix Aerospace]

From what I heard on The Story today, this is a recent development. They said something about using a bladder to draw in air as the helium is being compressed. Not really sure, I would have to listen again. Anyway, the end result being no wasted helium. I don't think this has been tried before on this scale. Plans for a ship to lift 250 tons are in the works. Here is the link for the report : http://www.thestory.org/mediaplaylist/popup

Huh. I should really read more about this stuff, then.

[Nuke]

so pretty much they control the balance by re-compressing the gas to alter the buoyancy instead of dumping ballast like they used to do. its a good idea, im surprised no one has ever tried to do that before. i like slightly heavier than air designs too. only give it enough buoyancy so that the propulsion fans with or without possibly aerodynamic lift are needed to get it off the ground. regardless, wind is still an issue.