Just a few data to show that in some particular cases two gases other than
hydrogen and helium can be useful to inflate balloons: natural gas (mainly
methane) amd ammonia.
Rough figures are as follows:
Specific weight Lift/volume Volume/lift Weight/lift
kg/m3 kg lift/m3 m3/kg lift kg /kg lift
Hydrogen 0.09 1.20 0.83 0.075
Helium 0.18 1.11 0.90 0.162
Natural gas 0.72 0.57 1.75 1.26
Ammonia 0.77 0.53 1.89 1.45
The first two gases had been discussed in depth at the reflector so no need
to insist.
Natural gas is readily available as domestic combustible. In my opinion
using it outside has no significant risk.
Ammonia has ample use in industry and agriculture (as a fertilizer). Can be
transported in liquid state (about 1.5 litres/kg) in closed containers
designed for relative low pressures in the 20-30 kg/cm2 range. Certainly it
is labeled as toxic but again its outside use have not significant problems.
If somebody has comments to do I beg of him (or her) to send it directly to
me, not to Reflector and if necessary I will do a final resumee.
Jose EA3VY
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