Hydrogen wouldn’t burn inside the balloon, because there’s no oxygen. If a fire started on the surface of the balloon, then it doesn’t really matter if it’s helium or hydrogen. Hindenburg would have happened no matter what it was filled with. IIRC, there’s an argument out there that hydrogen actually saved people in that case, though I don’t remember the physics of it all.
There’s some safety issues involving working with it on the ground, but you can mitigate that with procedures. Helium has an asphyxiation risk, especially when you’re working with enough to fill a blimp, so it’s not like it’s totally safe there, either.
Historically, the really bad thing with blimps/dirigibles is how the ground crew can get thrown into the air when they’re holding it down with rope and a gust of wind suddenly picks up. Hard to find numbers, but I wouldn’t be surprised if there’s more deaths involving ground crew operations of dirigibles than the 35 people who died on the Hindenburg.
gedaliyah@lemmy.world 3 days ago
The fact that helium is such a rare, irreplaceable, and scientifically useful material makes it wild to me that we use it to fill kids’ party balloons.
interdimensionalmeme@lemmy.ml 3 days ago
It’s not even being collected at the source (natural gas deposits) because it’s too cheap to be worth the extraction. This is because of the US liquidating its strategic reserve that it had been holding since the age of Zeppelins.
Also for unmanned aircraft, using helium instead of hydrogen is just crazy
5too@lemmy.world 2 days ago
Is it? Hydrogen is about half the mass of helium, but the trick is what you’re displacing to generate lift.
1 cubic meter of air is around 1.2 kilograms, depending on a variety of factors.
1 cubic meter of helium is around 0.18 kilograms, displacing the atmosphere to generate about 1.02 kilograms of lift.
1 cubic meter of hydrogen is around 0.08 kilograms, displacing the atmosphere to generate about 1.12 kilograms of lift, a shade under a 10% increase over helium.
That can be significant, depending on other engineering constraints; but is it “crazy” different?
(Numbers will vary with temperature and pressure, back of envelope calculations, etc. etc.)
humanspiral@lemmy.ca 2 days ago
H2 being 10% more lift while 500% cheaper still makes it the choice. A H2 economy is the path to 100% renewable energy, with a transportable fuel that in a fuel cell is also much more efficient than combustion engines/turbines. Lifting gas, chemicals, agriculture, rocket fuel, all of the existing uses for H2 is just icing on the cake.
interdimensionalmeme@lemmy.ml 2 days ago
0.18 to 0.08 is a gigantic difference, less than half the weight per cubic meter of displacement !!
Not only is cost an issue, but the larger the volume of displaced air, the bigger the dirigible, the harder it becomes to move through the atmosphere, more friction, more air resistance etc…
frezik@lemmy.blahaj.zone 3 days ago
Tom Scott visited the US National Helium Reserve and talked to the field manager of the facility. According to him, it’s not that big of a deal.
www.youtube.com/watch?v=mOy8Xjaa_o8
(Relevant bit starts around 2:58)
bladerunnerspider@lemmy.world 3 days ago
There are two grades of helium wells in terms of purity. Medical and kids’ parties… so that’s why it’s is still used for balloons.
aburrito@sh.itjust.works 3 days ago
Good news, it’s not that rare that that would make a difference. There’s plenty of it, just need different extraction techniques to further up the supply (unfortunately, that’s fracking lately iirc)