Not true. Most hydrogen atoms are are one proton and a negligible in mass electron. Most Helium atoms are two protons and two neutrons, and they mass approximately four times that of a hydrogen atom. So a hydrogen molecule has half the mass of a helium atom/molecule. (Unless of course it’s all deuterium.)
The Hindenberg cruised at an altitude of 650 feet. At that altitude you’re subject to thermals, crosswinds, rain, hail and icing The Akron crashed during a thunderstorm when it hit a downdraft so fierce its tail struck the water. Unless your passengers were happy with a bumpy ride, you’d pretty much be limited to flying only in the best weather, and for safety reasons you’d have to land if nasty weather threatened.
Skyship offered passenger flights in Switzerland for three years. The company’s website says its ships normally cruised at 1,500-3,000 feet, but could go as high as 8,000 feet. Still not enough to get above the weather, though. And there’s not much explanation why Skyship quit offering passenger service.
Dealing with the weather is a major problem. Less so back in the '30s when planes didn’t fly in bad weather either. The Hindenburg couldn’t even service NYC in the winter because of the threat of ice forming on the skin. There were plans to use Miami as a port for winter service, but nothing came of that. The Franfort-Rio route operated year-round. As to the actual flight experience my aunt described it as being really smooth. Not once in the entire flight did she not feel like she was on solid ground.
My apologies for the explanation outside of my realm. The end result is the same. One cubic foot of helium is only a little heavier than one cubic foot of hydrogen under the conditions used in an airship.
You can quibble over what a great difference is, but the superstructure of a dirigible does not need to be very heavy. It’s purpose is to maintain the aerodynamic and balanced shape of the envelope without pressurizing it. Composites wouldn’t change that very much. The skins would be somewhat lighter also. But I don’t think any of those factors make a dirigible practical for modern use.
Here is a cite for the conclusion (not the explanation).
Given their history, I don’t think you want to advertise a dirigible ride as “something you’ll only do once before you die.”
There are still sight-seeing vacation trains. Of course a train carries more people than an airship.
Unlikely. Trains can haul it about as fast at much lower cost (due in part to much better fuel efficiency). Aircraft can haul it much faster, and still probably more efficiently.
As others have noted, if lighter-than-air craft have any viable niche, it’s as a specialized high-cost novelty carrier.
Yes, you’d use composites because they’re light. It’s half the density of aluminum, with twice the modulus. That’s a big difference, and the reason that man-powered flying machines (like Daedalus) were made of composites rather than aluminum. A factor of two in weight is a considerable difference, especially if it can be made stiffer.
There’s one other, specialty niche for airships – heavy-lift vehicles. Suppose, for example, you want to place a three-ton turbogenerator in a power plant adjacent to and old but intact dam, access to which is across a nature preserve, or you want to transport some large heavy object to a mountainside or mountaintop structure. Rather than building a road that could handle the three-ton load plus a vehicle that could haul it through the middle of the preserve, or up the slopes of said mountain, you use a LTA craft with adequate lift to bring the heavy object in – and they can handle much heavier loads than helicopters.
There’s one othert point worth making – jet fuel is not always going to cost what it does today; as the cost of crude and of refining increases, the price of jet fuel will skyrocket. Plus we are using the figures for 1936 airspeeds in calculating airship travel times here – which to be frair should be equated to 1936 aircraft, not modern jets, or else a reasonable estimate of what it would be possible to fly an airship safely at today substituted for the 75-80 MPH of 1936.
I’m sorry. I left out a statement from that post that would explain why rigid airships are still not practical. You are correct, the use of carbon fiber should cut the weight of an airship superstructue significantly, but making airships practical requires more than that. Helium has been available for a long time, and I believe some of the early airships used steel frames. So the weight could have been cut by a third, and the danger of using hydrogen eliminated long ago. But all airships are dangerous because they are buoyant, and vulnerable to wind. They are also very slow for aircraft, and subject to the loss of the gas that keeps them up. The Graf Zeppelin managed a circumnavigation of the globe, but was extremely lucky to do so. Most of the airships ever made were destroyed in accidents, or decommisioned because of safety concerns. There is no way to make them safe to land or remain on the ground safely, and some were damaged in their immense hangars. And not all airships disasters were due to fire. If an airship were to spring a non-catastrophic leak in flight over the Great Plains it could land safely. But over an ocean or mountain range the landing could be catastrophic even if not from the result of a rapid descent. Because they are slow, dirigibles have to stay in the air for a long time to travel great distances increasing the chances of problems. The cost of using lightweight materials would increase the cost of an airship tremendously, along with the necessity to use helium for safety. Blimps and semi-rigid airships are still in use because they cost so much less to make, and the only reason for making a rigid airship is to exceed a practical size for a pressurized envelope. The outer envelope of a dirigible could be much lighter since it doesn’t have to contain the gas, but with helium the gasbags would have to be made of heavier material to keep from leaking helium rapidly. So all those factors together are the reason I don’t think rigid airships are now practical, and the reason there are none flying. Reduction in weight of materials alone will not resolve the other problems they have. It would also only serve to increase the maximum size of a rigid airship. Using carbon fiber composite construction in all the rigid components would only allow airships of the same payload capacity to be made smaller, and below a certain size, a non-rigid or semi-rigid would be much less costly.
Yeah, helium balloons provide almost as much lift as hydrogen because the lift is related to the difference in weight between regular air and the gas inside the balloon - so even though helium is around twice as heavy as hydrogen for the same volume/pressure, regular air is so much heavier than both that the difference between air and helium/hydrogen is almost the same.
How maneuverable are airships? It seems to be possible to design them to be dynamic so they can be neutrally buoyant at various elevations, so likely they would be able to go up and down fairly efficiently, so I’m curious as to whether they might be viable competition for helicopters for sightseeing tourism. Why do we have traffic helicoptors instead of traffic blimps?
As an aside, I seem to remember hot air balloons being relatively common when I was young (Calgary in the late 80’s/early 90’s) - there were times when there would be a dozen or more in the sky at once. I can’t remember the last time that I saw a hot air balloon in Calgary, but there must be some reason that they’ve gone out of style.
Thank you very much for using the proper wording for the effect I was trying to describe and explain.
Just came in to say that the FX spy-comedy series Archer did a funny show, “Skytanic,” on a modern passenger dirigible. You can see it on Hulu, I think.
You mean non-flammability.
[Dr. Nick]Who knew inflammable means flammable![/Dr. Nick]
Yeah! That’s the one I thought I was going to get called on :o I remembered Dr. Nick when I realized I did that. It was worse when I was kid and some things were still marked as ‘imflammable’ with an im- at the beginning.
Regarding the weather, would it be possible (perhaps with some future technology) to have zeppelins rise up to airline cruising altitude at 40K feet, or even near earth orbit at 80K feet? No pesky storms up there, and (especially for the latter) a much more spectacular view.
Earth orbit is a lot higher than 80K feet.
Granted, but I’m pretty sure you can see the curvature of the Earth at that height and the sky above you is black, so in terms of advertising . . .