A quick note on airships (2020)
caseyhandmer.wordpress.com
caseyhandmer.wordpress.com
> It is unfortunate that in the public mind, hydrogen as a lifting gas is associated with the Hindenburg disaster. Actually, hydrogen filled airships were extremely difficult to set alight. Just ask the Brits in WWI.
> The RAF could easily hit the German airships with gun fire, but couldn’t get them to ignite until they developed special phosphorus filled ammunition. They used sustained machine gun fire to rip a section of the gas bags to get the hydrogen to mix with air at their surfaces. Then, the small number of phosphorus burning bullets could ignite this hydrogen air mix. Even then, the RAF brought down very few of them.
> Because of this knowledge of how difficult it is to get a hydrogen filled airship to burn, there has been much speculation that the Hindenburg was sabotaged, set to burn deliberately, in a very public act of terrorism / economic / public relations warfare against the NAZI regime (and who could blame them?).
I had no idea that there were controversies regarding the cause of the disaster, nor that hydrogen was (arguably, at least) dangerous more in the public eye than in reality. I'd be interested to hear other modern engineering perspectives on the hydrogen issue...
https://www.irishtimes.com/polopoly_fs/1.4532919!/image/imag...
The story about him seeing Shaq is an interesting example. If you already know that Shaq lives in your apartment building, how much visual acuity do you need to make an educated guess that the large form waiting for the elevator is probably Shaq? There's also no one to tell us if he ever stood there talking to thin air thinking it might be Shaq ;)
It also seems like the kind of thing that would be difficult to give a satisfactory description of, so being coy about it is probably for the best.
https://www.thelancet.com/journals/lancet/article/PIIS0140-6...
Hydrogen is still widely acknowledged to be extremely flammable (see all the references here https://en.wikipedia.org/wiki/Hydrogen_safety). We have had many many disasters with hydrogen explosions pre and post-Hindenburg.
Otherwise, you are only be able to light the part of the fuel that leaked into the atmosphere.
Just wanted to chime in on this - it's impossible for most bullets to cause a spark, unlike what TV and movies show. Most projectiles (including the .303 round the British were using back then!) are lead with a copper plating, which are both non-ferrous metals.
Some Soviet era and US military ammunition (specifically m855 rounds) have a steel core, and those can cast sparks, but almost all handguns, and most rifles, aren't using ammunition capable of doing do.
I know next to nothing about chemistry or materials science, so offer no explanation of why this would be the case but a gas tank is difficult to ignite. The only layman intuitive answer I can think of is that a high speed projectile traveling through wood generates a lot more friction than one traveling through a liquid or gas, and something has to happen to that energy.
This scenario also fails to address the numerous failure modes of airships, including but not limited to the extraordinarily wide range of explosive mixes of hydrogen and air, as well as the rapidity and violence of hydrogen combustion and explosions.
I love the old sci fi where they extrapolate (incorrectly) new inventions such as the dirigible to the future.
This was well worth the read! Thanks!
https://www.pbs.org/video/hindenburg-the-new-evidence-3hjhu3...
But the idea of air travel where you watch the trees, rivers, pass as though you were on some "elevated train" is fascinating to me.
They could not have flown as high as modern jets, the air is too thin to breathe at that altitude.
Being limited to low altitudes means that practical airships cannot fly over the weather, and their low speed limits alternative destinations. Three of the four helium-filled rigid airships operated by the US were brought down by bad weather. These days, we have much better materials and weather forecasting, but I think operations would still be quite frequently constrained by the weather in most parts of the world.
On the other hand, if the stream of powered sightseeing aircraft over the Grand Canyon could be replaced by a few electric airships... Well, we can dream.
I did a hot-air balloon flight in Southern England several years ago and this low-level aspect was an unexpected bonus. The hills and rolling countryside seemed much more three-dimensional than I have seen from light aircraft, for whatever reason, especially in the low early-morning sun angles. It was also possible to hear ground noise (e.g. dogs barking at the balloon). You could also see the slow reaction of flocks of animals (e.g. sheep) that moved in their fields away from the balloon.
1. Put a few hundred well off people in luxury and slow air ship them to locations hard to reach by ships. Maybe with both top and bottom decks
2. ???
3. Profit
Everyone thinks of Hindenburg disaster when they think of blimps, yet infamous Titanic and Costa Concordia didnt sink the cruise industry.
The problem is that the infrastructure required for a blimp to land and takeoff might be significantly less expensive than a port but it's still many times larger than what an helicopter would need.
VIP services are banking on the new AW609 Leonardo[0]
Tradeoffs.
It's worth it to them to plop a bunch of marines down with helicopter speed faster/farther than you normally can with a helicopter.
The military generally doesn't uncritically accept "but muh safety and liability" arguments like private industry does because the cost of doing things less efficiently (trying to refuel helicopters in hostile airspace, airborne operations, etc) comes with a statistical body count as well and they have some degree of sovereign immunity.
In a non-military context the pros and cons would weigh differently.
But from other responses it seems that these aircraft can in fact auto rotate and glide in an emergency.
https://verticalmag.com/features/20112-flying-the-v-22-html/
"The V-22 is a tiltrotor and does not rely on autorotation for a survivable power-out landing. The wide separation of the engines and the ability to drive both rotors with one engine make a power-out landing extremely unlikely. However, if required, the V-22 can glide for a predictable run-on landing in airplane mode, much like a turboprop"
https://aviation.stackexchange.com/questions/22491/can-the-v...
The cost of helium is the reason you don't see the Goodyear blimps just floating around anymore.
As for the Hindenburg vs. Titanic: The titanic wasn't filmed going down. And the footage of a huge ball of fire with "Oh the humanity!" is a bit more dramatic than even the film representation of the Titanic sinking.
Back when the first ships failed causing the death of all the occupants , human lives were just not worth much , so humans kept building ships.
And also mass media wasn't there yet, so there could be no way to massively distribute content of a ship sinking and all the bodies floating around.
Same thing with planes, had we discovered flight in the Middle Ages we would have loaded 100+ people in wooden planes as fast as humanely possible because of the enthusiasm for the new technology would have vastly surpassed the fear of being harmed by it.
What are you talking about? The Goodyear blimps are still out and about providing video for major live TV broadcasts. It's not like they drain the helium and fill it back up each time it goes out.
For what it's worth, I see six scheduled appearances in two cities, all in January and February of next year. That's not a lot, especially when I used to see them about 3-4 times a year out in Montana (AKA, the boonies).
> It's not like they drain the helium
No, but they naturally lose helium at a fairly regular rate, since there's no blimp envelope systems that can prevent all helium loss. RC blimps, as an example, lose about .5% to 1% of their helium daily. Commercial blimps appear to have a couple of months until they've lost their bouyancy.
EDIT: A single Goodyear blimp requires approximately 300 mcf (1mcf = 1,000 cubic feet) of helium, and helium prices are around $700 per mcf when sold in bulk. That puts a blimp's helium costs alone in the $200,000 range for a blimp that can carry 14 people.
Back in 2000, the price per mcf was in the $40 to $50 range.
There's a common misconception that the Hindenburg failed because of hydrogen. That's not the case (he said confidently.)
The Hindenburg burned - it didn't explode. Hydrogen doesn't burn, it explodes. What burned on the Hindenburg was the skin, a mixture of all kinds of inflamable things including silver, dope and cotton. The same materials that made WW1 airplanes somewhat risky. When you watch footage of the Hindenburg you see the skin burning, the hydrogen escaping, and it falls to the ground, because, well, gravity.
Even then it happens really slowly - some people on the airship escaped by just waiting till it reached the ground then running away.
These days we regularly use flamable materials in transport - think Avgas, petrol, and to a lesser extent diesel and jet fuel (kerosene). The "hydrogen vs helium" issue is overrated in my opinion.
If it doesn't contain its own oxygen it can't realistically "explode".
(edge cases involving novelty chemical reactions that go solid/liquid -> gas by some other means notwithstanding)
You need precise fuel and oxygen ratios to burn things. Burning is basically just runaway oxidation. Burn enough stuff fast enough and you get an explosion. Contain a fairly rapid burn and you can fudge the same pressures as an explosion (this is what happens in a spark ignited combustion engine). Both these require the fuel any oxygen to be in sufficient proximity and mixture to each other.
Airships, propane tanks and other sources of fairly pure gasses can't explode until after you break them and let the contents mix them with the atmosphere. Now, a trashbag full of pre-mixed oxygen and acetylene. That will go bang real good.
>When you watch footage of the Hindenburg you see the skin burning, the hydrogen escaping,
You see the hydrogen burning as it mixed with the atmosphere in the presence of an ignition source. The airship casing on its own doesn't have enough fuel to burn that energetically.
> The "hydrogen vs helium" issue is overrated in my opinion.
I agree but for totally different reasons that boil down to "people overrate risks they don't understand".
Static electricity (from a potential difference with the ground, St. Elmo's fire, or other sources) likely also contributed. Forensic analysis strongly supports leaking hydrogen from the aft part of the airship, given the nose-high, tail-low attitude and handling difficulties.
A myth has taken hold that the “paint” on the Hindenburg’s skin — rather than its flammable hydrogen lifting gas — was somehow responsible for the Hindenburg disaster at Lakehurst, and this myth somehow persists even though it has been debunked by photographic evidence, scientific analysis, historical research, and even the TV show MythBusters.
https://www.airships.net/hindenburg-paint/
The Mythbusters episode:
Then a reproduction lounge on the Hindenburg[3], compare with any of these on a cruise ship[4]. Ships are roughly as luxurious as you want to spend money to get, rivalling any hotel. (Water is ~750x denser than air, does that mean it can buoy up 750x more luxury per passenger for the same displacement vessel?)
[1] https://www.myswissalps.com/docs/SystemLibrariesProvider/swi...
[2] https://i.redd.it/abf8ipo9noj41.jpg
[3] https://www.myswissalps.com/docs/SystemLibrariesProvider/swi...
[4] https://duckduckgo.com/?q=luxury+cruise+ship+lounge&t=ffab&i...
https://en.wikipedia.org/wiki/CargoLifter
The German wikipedia article has a lot of more details (use Google Translate etc.)
https://de.wikipedia.org/wiki/Cargolifter_AG
And they planned to use helium:
Hence boomsupersonic and the like. Or some hyped loops for tunnel rats. Or rattling rockets by whomever.
I don't know where this assumption comes from. Airships were not silent, nor would you ever want to promenade the deck. These things moved very quickly. The wind/engine noise was considerable. If you opened a window you would be hit with a 50+mph blast of wind. Only during takeoff (liftoff?) and landing would there be any sense that you were floating as opposed to flying.
>> I think a modern Zeppelin could be built for less than ten million dollars.
No. Just no way. There is no possible scenario whereby one could develop a new over-ocean passenger-carrying aircraft for 10mil. Talk to Boeing/Airbus. You probably need to double that number and add at least one zero.
I can't wait to see this thing in the air, even just the hangars are quite an awe inspiring sight.
I'd also love to see more long-distance shipping move to advanced clipper ships using modern materials, computer-controlled rigging, highly optimized sail and hull designs, etc.
It’s technically feasible but economically infeasible right now, the headline below notwithstanding. https://www.greenbiz.com/article/sustainable-aviation-fuels-...
Also, the overall energy efficiency is very poor. A plant creating synthetic cerosene just opened in Germany, and the reporting said the electricity->h2->cerosene->aircraft movement efficiency is 10-15%. Ouch.
Good thing the CO2 doesn't stay there forever.
> Also, the overall energy efficiency is very poor.
And energy efficiency is a good proxy for economic viability when you are comparing similar things, but completely useless when you comparing it with something. Why does the 10% efficiency matters?
(By the way, expect that to increase. It always does.)
https://en.wikipedia.org/wiki/Environmental_effects_of_aviat...
The 10% combined efficiency of the three energy conversions matter because energy itself isn't 100% green. With the current energy mix, there are more emissions from synthetic fuels than fossil ones.
edit: Ah yes, see https://www.airbus.com/newsroom/stories/ascend-cryogenics-su...
addedit: Or less ambitious https://www.ainonline.com/aviation-news/air-transport/2020-0...
Just for fun: https://docs.google.com/presentation/d/1r6CPFJ1AX1ZULacguTf6...
I’ve wondered about a sea anchor turbine, where the lifting power changes from day to night would spin the turbine, and provide enough power to keep the airship or platform in place (eg, to do cloud seeding duties)
Riiiight? :)
The (defunct) Magenn co. had the idea of making Magnus effect pontoons that would stay aloft and generate electricity.
https://newatlas.com/magenn-mars-floating-wind-generator/111...
http://energykitesystems.net/0/Magenn/
https://en.wikipedia.org/wiki/Magnus_effect
I like to say that the Magnus effect is to the wing as the wheel is to the sled runner.
(BTW, the link on your HN profile has some sort of problem. "connection has timed out")
Do you know this paper? It’s a fave. Magnus effect ftw! https://royalsocietypublishing.org/doi/10.1098/rsta.2012.008...
I also didn't know someone seriously considered giant nuclear airships? Did this come straight out of Hollywood, or was it the other way around?!
But there is something in these concepts I don't get. In the depictions of the 'promenade' there is always solid ground where you stand on, and then have to lean over to look down through angled windows. Why not make at least parts of the promenade fully transparent, like it is on some observation decks in tourist destinations? Also the cabins seem to be a waste of room. I think something between a capsule hotel and https://sleepbox.com/ would suffice. In this mode of transport everything should be about maximizing the special viewing experience. The rest for lounge, bar, restaurant, salon, maybe selfcleaning toilets and washrooms. If tired? Sleep. Why would I need so much room for sleep? Given a travel time of some days to maybe two weeks? Just watch, watch, watch and relax :-)
But a glass bottomed ballroom would be a nice touch, if you ask me.
Now I really want to know where the "Zeppelin region" is located in Germany...
I have often wondered why no one has tried to design and build an airship with an envelope in the shape of a lifting body. The structure might have additional weight to hold the desired shape, and it would have to take off like an aircraft, but wouldn't the added lift provide significant advantages? I know I must be missing something fundamental.
Can someone more knowledgeable tell me what it is?
https://www.hybridairvehicles.com/our-aircraft/airlander-10/
It's possible to build a continuous rail link from the south of Africa to the British Isles, Siberia, and Malaysia.
Tunelling across the Bering Strait would be within reason for an Asian-American link.
Crossing the Atlantic is appealing as population centres are closer to both coast, though sea distances are greater. One possible answer might be a "floating tunnel", of the type envisioned for use in crossing Norway's fjords. Suspended from buouys and anchored to the seafloor, at a depth of about 30m, muliple bores could carry passenger and freight rail traffic. One possible route might extend from Scotland via Iceland and Greenland to the Labrador coastline.
For the floating tunnel concept, see:
https://en.wikipedia.org/wiki/Submerged_floating_tunnel
Transit times might range from 15 hours (at about 240 kph / 150 mph) to as little as 2.5 hours in a hyperloop-like evacuated tube at 1600 kph / 1,000 mph. The former is about a quarter the speed of present-day jet airliners, making short day excursions between continents infeasible but allowing for an overnight "hotel train" or working daytime trips. At higher speeds, service is comparable to present aircraft, and at the (admittedly unlikely) extremes, several times faster.
Similar crossings could be reasonably be made to Indonesia and on to Australia, crossing from Singapore, then to West Java and Timor Leste, and across the Timor sea to Darwin. A southern Atlantic crossing between Recife and Monrovia might also be possible.
There are of course formidible costs and risks. But the technology and routes are at least within the realm of possibility.
A north-Atlantic rail crossing was amongst the concepts mooted in a BBC piece some years back:
https://www.bbc.com/news/magazine-23969607
A more complete proposal is in this 2004 PopSci article:
https://www.popsci.com/scitech/article/2004-04/trans-atlanti...
Apparently also a 1935 film:
But it would be very vulnerable and probably protested for all sorts of business and political reasons. Just look at what happens with proposed pipelines, high-speed rails, the bitching about where to put stations, the NIMBYism about where not, and so on.
In this case there could be less NIMBYism, because open-seas, but think of the ship builders, and the giant complex of companies operating the built ships. Wouldn't you think they object to that? Just look at what ferry operators did when some tunnel or bridge opened, making them obsolete.
So we have them, and their interests, against a potential network of submerged floating tunnels enabling all sorts of nice things, making them almost obsolete, too. Similar for Aerospace. 500kph seems doable without vacuum. Half the speed of air-traffic. 350 to 400 kph even more so, and already IS in operation at 350. Now imagine freight trains running at 250 to 300kph on separate tracks. Which you would want to have anyways, if only as reserve/backup for maintenance reasons. And now imagine a grid of these. Criss-crossing the seven seas, and having transport-hubs/nodes, switching yards, resort cities, free towns, permanent in-situ sensors, whatever, out there.
Can't have pirates though, or war.
What do you think about that?
edit: I'd opt for smelting all the container giants, bulk carriers, and similarly obsolete stuff to build this. With nuclear power, if need be. I don't care. The same for most airplanes, because less noise.
Seawards, Ho!
ARCHER: Lana, no! You'll kill us all!
LAMMERS: For the last time, you idiot! It's not hydrogen! It's helium!
LANA: And what about that are you still not getting, exactly?
ARCHER: Well, obviously the core concept, Lana. Sorry I didn't go to space camp.
> It’s not called a Zeppelin unless it comes from the Zeppelin region of Germany, otherwise it’s just a sparkling airship.
It had three steerable propellors, two steerable. This made it far more manuverable than classic airships. No more needing an army on the ground to tie the thing down.
DARPA and Lockheed's Skunk Works built a airship in 2017 or so with even more steerable fans. That thing could fly itself out of a hanger, take off, return to base, land on a short runway, and taxi to the hangar.
High winds on the ground remain a problem. Just too much sail area.
Here's a comment from a couple of years ago with links to some Zeppelin information and my photos from the flight: