Hydrogen has more lift, it's cheaper, and it's easier to contain
(molecule's roughly twice as big, doesn't slip through the pores
so quickly).
For the record - yes, the hydrogen molecule is actual bigger in
the 'long 'dimension than helium because the helium 'molecule' is
the *same* monatomic unit as the atom. IOW there is NO such animal
as He2, and the helium atom itself is quite compact, due to the
higher bonding energies of the electrons. OK that much is true.
But the decision to use helium these days is both political and
economic - but not really related to any significant (true
scientific) explosion risk. The so-called 'cheapness' of hydrogen
quickly disappears when other cost factors are added-in.
Furthermore, it should be noted that the real problem is that
hydrogen IS considerably harder to contain - but not because of
its molecular size. It is harder to contain only because it
quickly forms ions and free protons at the interface of many
materials, even non-electrical-conductors ... and, yes, the lone
proton IS indeed millions of times smaller than any molecule.
The nucleus is ~10,000 times less diameter than the atom, and the
volume size difference would be the square of that - now that IS a
huge difference compared to helium. Many nonmetals, even ceramics,
are good proton conductors (and that is why we have fuel cells)
and in general the 'problem' with hydrogen - and its resultant
higher "net cost" was in finding a thin non-porous AND
non-proton-conductor for coating the fabric skin of the LTA
airships to prevent losses.
There is little problem with helium 'bags', which need no
complicated coating as does hydrogen. Almost any rubber or plastic
based paint will contain helium whereas most of these same
coatings are proton conductors. The proton is extremely mobile at
the quantum level. The cost and extra weight of hydrogen
*containment* in the LTA, therefore outweighs the much higher cost
of helium compared to hydrogen, and when you add in the higher
weight of the special coatings (often double) then there is little
'net' weight saving over helium.
The real 'problem' with Hindenburg - as all careful historians
have noted: 'paint' not the 'fill.'
That and Germany having no helium resources. Which is what makes
this subject matter "On Topic" for LENR as arguably the very
genesis of LENR is to be found in the German (European) attempts
to manufacture helium from hydrogen - since the USA had the
monopoly on helium in that time period.
It was the airship coating - the paint - which caught fire
initially. The coating was a resin containing aluminum powder -
thus the 'silver' color. The powdered aluminum in the paint, and
probably in proximity to an engine exhaust manifold, caused the
fire, not the hydrogen, which when it burns produces no color - so
you would have seen no 'fire' anyway from just hydrogen, had that
been the problem.
All of this is well documented in the literature by now, but as
these messages on Vortex demonstrate, not well understood or
appreciated by even the most interested observers.
Jones
- Re: Air Rotors to Ship this Fall Jones Beene
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