As a deaf person, very much appreciate the video is subtitled. Thank you for sharing, I will watch later.
Having not watched the video, obviously hydrogen is a bad idea, but I’d also say no to helium airships until it becomes a replenishable resource through nuclear fusion.
Kerosene in airplanes is actually significantly more dangerous. Airships with hydrogen are the only realistic option and the safety of it is only a minor engineering problem today.
Hydrogen is a nuisance of a gas, though - it has a very wide combustible range of mixtures.
But an airship envelope containing multiple lifting units of hydrogen could be passivated by filling the envelope with a non-combustible gas like helium.
So, there’s a big sausage providing structure and that’s full of helium (or nitrogen, or CO2, or anything else which doesn’t react with hydrogen in normal conditions)… and it contains balloons full of hydrogen. If one of them springs a leak, the leak won’t be going into an environment that supports fire. And if the leak then proceeds into surrounding air, the hydrogen is hopefully diluted beyond its combustible range.
Considerably less expensive than using helium only. But considerably safer than using hydrogen among air.
Do you have any idea how much fusion you’d have to do to have it be a significant source of helium?
*edit: I was curious but had to guess ranges to do the maths. To fill a single Flying Whale airship, a 2 GW fusion plant needs to run between 90 and 850 years.
Technology and materials sciences have come a long way since the 1940s. For example, we can probably skip sealing the gasbag with solid rocket fuel. Hydrogen gets better lift than helium, it’s not a limited resource with higher-priority medical uses, and doesn’t require petroleum-style drilling. It’s flammable, as we saw in the past, but with modern engineering, modern materials, non-conductive pressure vessels, emergency release valves, no ignition sources or sparks in proximity, it seems like it can be done pretty safely.
Until recently, I think, modern aviation had been admirably safety-focussed, in everything from engineering to operation. I’m not a fan of the airline industry and especially Boeing’s recent shortcuts, but I think solarpunk is very much about picking and choosing which parts of our society to keep and which to reexamine to see if they can be done better. Aviation safety is one of those things our society does know how to do well, and that seems very much worth keeping to me. Overall I trust aviation engineers to find ways to do hydrogen airships safely.
Part of the safety focus is from sticking so many people in the same fuselage - which, being big, has no individual rescue equipment and cannot be brought down by parachute either - so nothing critical is allowed to fail.
Side note: that’s not the only possible model, however - one can also design heavier than air craft that are smaller, almost passively safe (falling controllably without power, at somewhat above parachute speed), and design small aircraft that have rescue systems (parachutes which can land the whole aircraft).
Size itself is then a function of economic realities (air travel has undergone explosive growth).
Blimps would have to somehow fit in. Having considerable air resistance, blimps cannot travel as fast. Being unable to travel as fast, they would fall behind at moving X people per hour - while a blimp makes one roundtrip, a jet aircraft would make multiple roundtrips.
If however a jet aircraft is deemed environmentally unsustainable on account of fuel use - then the milestone to compare a blimp against will be a propeller-electric aircraft. Which is more limited in speed, requires charging time, is more limited in range - and therefore makes less roundtrips in an unit of time.
From one viewpoint then, the success of airships thus depends on whether fast aircraft can reduce their environmental footprint. If they can, blimps will not be widespread. If they cannot, blimps might become widespread.
Overall, a fast airplane is effective at getting results (transporting people) but not necessarily efficient at doing that. There is perhaps only one aspect where a high-powered aircraft is more efficient… use of space. But space is not a scarce resource in the atmosphere. Only on the runway.
Out of the previous considerations, I come to the conclusion: blimps probably won’t replace airplanes. Especially for longer trips, having to wait less is what makes people prefer speedier travel. Blimps cannot provide that. However, airships might carve out a niche for servicing shorter routes and local traffic.
Blimps would have to somehow fit in. Having considerable air resistance, blimps cannot travel as fast. Being unable to travel as fast, they would fall behind at moving X people per hour - while a blimp makes one roundtrip, a jet aircraft would make multiple roundtrips.
Blimps are far worse than airships; the fundamental advantage of airships is that they scale up well (doubling the size nets you 8x the volume), which blimps just don’t. And blimps are far less safe, due to their gas bags needing to be pressurized where airships’ gas bags can be unpressurized. More specifically, if you puncture a pressurized gasbag, then its contents spray out due to the pressure, which in the context of hydrogen would mean it rapidly mixes itself into large amounts of hydroxygen just begging to explode, whereas unpressurized gasbags will just slowly diffuse hydrogen like piss in water. Still potentially dangerous, but far less so.
Weirdly, when it comes to cargo airshipping, airships are actually faster than cargo freight (not to be confused with parcel freight, which is what post (e.g. Amazon packages) uses). Cargo freight takes 4-5 days, which airships can easily beat via shipping point-to-point.
Yes, but for passenger service rather than cargo. Passenger jets are too fast, too uncomfortable, and cause too much pollution.
Because I think it’s bad economics to try to transport finished goods over long distances quickly. It’s better to transport raw materials long distances slowly (ship and rail) and employ people to manufacture things near where they are needed.
What’s the advantage to transporting raw materials as opposed to finished goods? You’re giving up economies of scale and support infrastructure, I’m not clear what you are getting in return.
Passenger jets are too fast
People complain about that? If they were too fast - impossible concept - then I wouldn’t complain. After the first two hours I don’t need to see the empty sky so much, and judging by the video panel use I’m not in the minority thinking so. If it became faster to get between the biggest 10 airports in the world, because of some super passenger rocket, then I’d be all for it. Even the best flight home from NZ is 16 hours I can’t ever get back; and even the best flight is still a horrible time stuck in a tube with a few hundred people I don’t want to know by smell.
Airlines are too fast in several senses. First, people don’t usually need to get somewhere as quickly as an airline allows. Someone who is really on urgent business can use telepresence or a charter instead. Second, the airports on either end of a trip are frequently too slow, making airlines and example of “hurry up and wait”. Third, airlines move people through timezones very quickly, exacerbating jet lag.
I agree with you that airlines are too uncomfortable even for their speed to overcome. Slow travel can be much more comfortable. For example, many people are willing to spend days on trains and cruise ships.
Yes.
That is all.
Very comprehensive video.
H2 is by far the best gas choice, and part of H2 economy.
airships are also a great vehicle to transport H2 as needed without pipeline permitting. Providing green energy resilience to anywhere. They are faster than trucks for distance cargo.
Designs that include wing based lift are a winner. Aircraft attitude can be changed by compressing to/from back/front of airship, and management of cargo/ballast/pull force on ropes is made easier.
They mentioned using compressors for ballast. Having center rigid sections able to hold H2 or air or vacuum can be used to move H2 out of the center before landing, and then replace cargo with air for ground/rope attachment stability.
Another airship application is replacement of yachts. There is very little weight variation from residents and “groceries” being inside vs out. There is massive solar production capable surface that can generate H2 fuel for power, and then get water back from consuming the fuel in fuel cells. 20ft fiberglass trailers weight 1mt. 900 m^3 of H2. 1500 m^3 for people + baggage. 2500 m^3 for solar + fuel cells + electrolyzers + prop engines. 25m long airship with 1m extra length for each extra ft of “furnished cabin+luggage space”.
Another airship application is replacement of yachts.
I think we have enough of those. In fact, we need less, both water and air yachts.
Something that happens with self driving cars is that you can live in your car without having to park it anywhere. Airships hovering is a similar “freedom”.
That makes sense to me - the word yacht might be implying too much a certain use case (it’s the name of a class of vessel but I think it also says ‘rich people toy’ on first impression). But house boats have been around for a long time and when they’re someone’s primary residence they sometimes represent a cheaper model of living, not unlike a mobile home. An airship houseboat is an interesting idea, I think it showed up at the end of Cory Doctorow’s Walkaway.
I like your math here. You should bring this up with !hydrogen@fedia.io , the largest Mbin magazine. Somehow nobody on slrpnk.net subscribes to them, so they’re not that well federated. While they mostly focus on H2 power, I agree that hydrogen should return as a lifting gas for airships.
