Yes, helium costs would be a problem for large-scale use of airships. Yes, it’s possible to use hydrogen in airships safely. This has been noted by many people.
Hydrogen has some properties that make it relatively safe:
it’s light so it rises instead of accumulating on the ground or around a leak
it has a relatively high ignition temperature
and some properties that make it less safe:
it has a wide range of concentrations where it will burn in air
fast diffusion, that is, it mixes with air quickly
it leaks through many materials
it embrittles steel
it causes some global warming if released
Regardless, the FAA does not allow using hydrogen in airships, and I don’t expect that to change soon. Especially since accidents still happen despite the small number of airships.
In any case, the only uses of airships that are plausibly economical today are: advertising and luxury yachts for the wealthy. Are those things that you care about working towards?
Have to divide by number of airships, which probably makes them less safe than planes, if not cars. I think the difficulty is mostly with having a large surface-area exposed to the wind making the ships difficult to control. (Edit: looking at the list on Wikipedia, this is maybe not totally true. A lot of the crashes seem to be caused by equipment failures too.)
Are those things that you care about working towards?
No, and I don’t work on airships and have no plans to do so. I mainly just think it’s an interesting demonstration of how weak electrostatic forces can be.
Yes, helium costs would be a problem for large-scale use of airships. Yes, it’s possible to use hydrogen in airships safely. This has been noted by many people.
Hydrogen has some properties that make it relatively safe:
it’s light so it rises instead of accumulating on the ground or around a leak
it has a relatively high ignition temperature
and some properties that make it less safe:
it has a wide range of concentrations where it will burn in air
fast diffusion, that is, it mixes with air quickly
it leaks through many materials
it embrittles steel
it causes some global warming if released
Regardless, the FAA does not allow using hydrogen in airships, and I don’t expect that to change soon. Especially since accidents still happen despite the small number of airships.
In any case, the only uses of airships that are plausibly economical today are: advertising and luxury yachts for the wealthy. Are those things that you care about working towards?
Your ‘accidents still happen’ link shows:
One airship accident worldwide in the past 5 years, in Brazil.
The last airship accident in the US was in 2017.
The last airship accident fatality anywhere in the world was in 2011 in Germany.
The last airship accident fatality in the US was in 1986.
I think that this compares favorably with very nearly everything.
Have to divide by number of airships, which probably makes them less safe than planes, if not cars. I think the difficulty is mostly with having a large surface-area exposed to the wind making the ships difficult to control. (Edit: looking at the list on Wikipedia, this is maybe not totally true. A lot of the crashes seem to be caused by equipment failures too.)
No, and I don’t work on airships and have no plans to do so. I mainly just think it’s an interesting demonstration of how weak electrostatic forces can be.
I think this is mostly about how weak air is against dielectric breakdown.
On the other hand, the hydrogen pushing against the airship membrane is also an electrostatic force.