zlacker

Isn't H2 better because better lift and being a molecule of two hydrogen atoms it is not quite as slippery as helium and quite easy to make?

From wikipedia "lifting gas"

"Helium is the second lightest gas (0.1786 g/L, 14% the density of air, at STP). For that reason, it is an attractive gas for lifting as well.

A major advantage is that this gas is noncombustible. But the use of helium has some disadvantages, too:

    The diffusion issue shared with hydrogen (though, as helium's molecular radius, 138 pm, is smaller, it diffuses through more materials than hydrogen[4])."

>>airbre+(OP)
and at this scale it seems like the hazards of h2 would be pretty minor. You're not exactly going to have a Hindenburg situation with only a couple dozen liters of H2.

>>mlsu+n8
No but you might get serverely hearing impaired..

>>airbre+(OP)
It really seems like there is no downside to this, other than the minuscule risk of a low-altitude puncture + spark causing a fire, and even there the exposure is small because the amount of hydrogen gas is so much small.

Not to mention that hydrogen is free for anyone who has water and a power source.

>>airbre+(OP)
The diffusion is the main advantage of using helium, it takes ~3x longer to leak out, which directly affects flight time.

Hydrogen is actually harder to buy in my experience, helium is sold everywhere for cheap in small canisters for parties, whereas the second requires like, industrial welding suppliers that will want to sell you a large tank for a few thousand or making your own electrolyser and compressor. There's no common use case for it you could piggyback on.