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Statistics: Posted by Jockla — Thu Sep 25, 2014 11:42 pm
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Dirigibles have been around for a long time and are extremely safe and efficient. This is not "science fiction becoming science fact," it is merely a very positive evolution of an existing technology.
I do not believe the claim of 100 mph. Airships have very large surface area, therefore massive drag. To propel one of these at 100 mph would require so much energy it would be impractical.
The fire that destroyed the Hindenburg was not the hydrogen burning. It was the skin of the airship burning. The skin was a lightweight fabric made airtight by a doping compound which was highly flammable, and was ignited by the spark. The people who died in the tragedy were those who panicked and jumped to their deaths. Those who remained on board were mostly unharmed as the gondola settled slowly to the ground as the hydrogen escaped.
Mixing nitrogen (or any other gas other than helium) with the hydrogen will do no good. It will just make the gas heavier and therefore less buoyant. Helium and hydrogen are the only gasses that will work. Hydrogen is not free or 'easy" to produce. It requires energy to drive electrolysis (the separation of hydrogen from oxygen of the water molecule). But it's still much cheaper and more easily available than helium, which it would be good to conserve for applications where there is no other substitute, such as welding aluminum or deep-sea diving.
An airship held aloft by a vacuum is pure fantasy. It's not science and not even science fiction. There is no material known or reasonable to expect that is at once strong enough to resist the atmospheric pressure of 32 pounds per square inch and light enough for an airship which must, in the end, be lighter overall than the amount of air it displaces. A vacuum bottle will keep your coffee warm, but it will never be lighter than air.
Dirigibles are great for lifting and moving very large, heavy loads, and for carrying them over land or water. Equipped with luxury accommodations they are great for moving people who are not in a hurry. (Sort of like cruise ships.) They are susceptible to bad weather, but with present-day weather satellites, that can be worked around. They are very efficient. The flammability of hydrogen is not a problem except for the public perception. The hysterical radio announcer who famously reported on the crash of the Hindenburg did the world a great disservice, and subsequent reporting which emphasized the hydrogen rather than the real culprit: the flammable fabric doping, sealed the demise of the dirigible. Nowadays there are bound to be non-flammable materials. Dirigibles won't replace airplanes, because airplanes are much faster, and people are so often in a hurry. But there are many applications where they are ideal. Maybe the aircraft reported on in the article will re-introduce this promising old technology to a world badly in need of more efficient transportation.
Dale is actually very forward-thinking in using dirigibles in his books. They are not science fiction and they are not fantasy, though Dale does use fantasy for their propulsion. There is no technological reason not to build lots of them right now (with, of course, conventional motors).
Statistics: Posted by daniel1948 — Wed Jun 11, 2014 8:41 pm
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The engines would be below, if hydrogen escapes it will rise, not fall to whatever engine is in use.
I am not discounting the danger, just saying its a lot more manageable then a rocket...
We could use halon systems and emergency cut offs if for some reason the engine caught fire. We could also encase the engine in its own compartment, below where any leaking hydrogen won't reach easily.
We could use sensors that cut off the engine if all the above fails. Lastly less than half the the people died on the Hindenburg when it exploded and went down, which had a smoking section. That means despite the "danger" it was still safer then a jet airplane crash where there is usually a 100% mortality rate. Airplanes are much more dangerous statistically and using common sense, yet we have a pretty good safety record with those.
That said, dirigibles are probably to slow to really catch on for people who want fast travel. It would probably be used more for shipping/freight.
Statistics: Posted by David — Thu Mar 20, 2014 2:42 pm
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It is the smallest atomic particle and has the ability to sneak through other molecules - through the smallest holes and doesn't require much to ignite. Overall, something that anyone would need to be cautious of.
Statistics: Posted by ArgyrosfeniX — Thu Mar 20, 2014 9:18 am
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I think there is a programmed fear of hydrogen from when we were in grade school, learning about the Hindenburg and how dangerous it is, yet we use other combustibles in all our vehicles be them ground or air. We are programmed to fear it more than other combustibles, despite the fact we have come a long way in safety from back then.
Statistics: Posted by David — Wed Mar 19, 2014 4:37 pm
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Helium is stable, but we're running out.
(What, you haven't heard about the great helium shortage? No joke, Google that one.)
It's dangerous, but getting around explosions is something we're sort of good at, as a people.
Statistics: Posted by PS Power — Wed Mar 19, 2014 2:14 pm
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Kinda scary...
Statistics: Posted by ArgyrosfeniX — Wed Mar 19, 2014 12:21 pm
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I have no idea if anything would work for that! It sounds reasonable, if anything can be found.
Statistics: Posted by PS Power — Tue Mar 18, 2014 12:57 pm
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We don't need perfect containment, since it's nearly harmless when it leaks. And it will leak. Much like a vacuum, total containment is difficult to achieve.
So, rather than wait fifty to three hundred years to work it out, we can have cheap heavy lifting devices up in a year or two, that can work almost anywhere in the world.
The big problems with airships to my way of thinking are:
1. Public perception. "Oh, the humanity!"
Everyone expects them to explode, even if we have much better controls in place now.
2. Speed. Or the lack of it.
An airship can travel at about twenty miles per hour, under power, in calm winds. Less in most cases. At least if they're going to remain cost effective. On the good side, we can run them off of solar, using the latest materials.
On the bad, we're used to getting everything now. Now I said!
3. Initial investment for uncertain payoff. Without a large and obvious economic payday in the winds, few large companies (i.e. the ones with the cash to back such a project.) will attempt large scale airship practices. This may eventually change, if something better doesn't come along to replace fossil fuels, but until/unless that takes place, this will remain in the category of "interesting hobby."
4. Poor overall handling compared to modern aircraft.
They can't really outrun weather, and it's a bigger factor for them than for an airplane of helicopter. This means having the ability to tie down and deflate (Or go into a hangar) and good weather services, in most locations that the ships run in. This is really hard to do over the ocean, at the moment. That means being very aware of the weather. This is a thing we can do now, however, which will help prevent loss.
On the pro side:
1. They can carry very large payloads. Much more, far more cheaply, than any other form of air, or ground, travel. Especially if the system is worked out to run without fossil fuels.
2. They are in less danger of crashing and harming civilians than planes. They can crash, normally due to weather, but that was always rare. Once the explosion problem is taken out of the picture. They just move to slowly for that to be a vast issue.
3. Very smooth ride, making pleasure craft far more enjoyable. Comparable to a cruise ship, if done right.
4. Child friendly. Even a toy blimp or airship will be much to big to swallow! Yep, kids will love these things!
Statistics: Posted by PS Power — Sun Mar 02, 2014 5:36 pm
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I worked up a similar design to that one years ago. (Which isn't odd, since I cribbed off the same basic plan that they did for it, using a partial airfoil formed from the balloon in order to create massive lift, even at slow speeds.)
On the good side there is incredible amounts of lift that can be generated. On the negative, everyone keeps wanting, even insisting that we use helium for the darned things, but we're running out.
Hydrogen is the plain way to go, but the public doesn't trust it yet.
On the good side, the things can travel into a lot of places that we'd never send a plane at all. They don't do well in storms however.
Statistics: Posted by PS Power — Sat Mar 01, 2014 5:04 am
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