First question that comes to my mind is, “How much helium will this use if it scales”. Helium is still non-renewable, and it’s still pretty critical for MRIs among other critical analytical instruments.
Probably insignificant. But it’s still the question I have.
I think to have once read that World War I fights against Zeppelins showed that igniting the hydrogen proved to actually be quite hard. Only when they were able to open significant holes and used special ammunition did that work. Not enough hydrogen would escape and mix with air and remain in one place to accumulate to cause an explosion. There needed to be a big hole first for enough hydrogen to mix with air, plus the spark to ignite it.
That was WWI airplanes over Britain attacking Zeppelins with their machine guns.
There were a lot of compartments too, it was not all one giant space of hydrogen.
> That autumn, the British pilots deployed a new weapon. No longer dependent on dropping bombs or explosive darts over the side, nor on the standard machine-gun ammunition that appeared to have no effect whatever on the giant gas-bags, the home-defence squadrons now filled their ammunition belts with a mixture of tracer and newly-designed explosive and incendiary bullets. The idea was to blow a hole in the fabric of an airship and then ignite the escaping hydrogen as it mixed with air.
Of course, once successfully blown open and ignited it would go up in flames like a torch. But it wasn't quite that simple to get to that point.
It’s lighter than air so the flames burn hot but the gas is going up too - and the ship is losing lift and going down at the same time. It’s a good combination if you have to be on fire.
The main key would be a gasbag that’s not flammable.
Piggy-backing on your comment at a tangent - how did they make such large quantities of Hydrogen in the early 1900s (and store and transport it safely)? This[1] has some interesting reading on it; there were gas cylinders but no standardisation of valves, not good lubricants for compressors, a different set of pipes for airship filling and airship topping-up, some stations which could remove and re-purify the Hydrogen, and two different methods of pre-war and post-war production are described.
This[2] has much more detailed history of the options, including a Popular Mechanics article from 1908.
Depends on your metric. Sulfuric acid and iron is pretty simple if you don't count the blast furnace. Certainly a lot simpler than a gasoline generator. If you have grid power and a diode, electrolysis gets simpler --- though you probably want at least a transformer. Hydrolith is probably simpler and lighter than sulfuric acid and iron, though.
It's simple but surprisingly fickle, even more if you want industrial amounts of hydrogen safely. This is an example of a home setup and nontrivial considerations that went into it:
"Hydrogen can be made safe, and is renewable. For something like this to work we need to move past the Hindenburg."
Seems to me you're right. In some ways it's a damn shame that reporters and movie cameras were at Lakehurst that fateful day, unfortunately their presence set back airship development at least a half century.
The WWI matter that nosianu has raised about how hard it was to bring down hydrogen-filled airships due to the difficulty of igniting the hydrogen is well known and it ought to be a starting point for its reintroduction. New containment materials combined with what we've learned from the Hindenburg should also do the trick. On a regulatory point, if you kept hydrogen to cargo-only airships and where possible even routed them around heavily populated areas (at least until well proven) we could see hydrogen make a comeback.
Also, Hydrogen has that other advantage, it has about 8% more lift than helium. It occurred to me hydrogen's risk could be further mitigated if it were used in combination with helium where they shared the lifting - the hydrogen able of being vented, etc. and the helium bagged separately as permanent/primary buoyancy. Reckon that with a fresh look we've many new options to explore.
Probably insignificant. But it’s still the question I have.