Water vapor is indeed the main reason to NOT use compressed air in
tires for critical use. I can only speak from my racing experience, but
when we set our tire pressures, it is only a starting point and we must
fine tune from there. You see what is important is the hot pressures,
and how much the pressure builds from the cold setting. My tires like
to be at 26 psi at operating temperature, more than that and they get
to sliding too much and building even more heat, and sometimes when
using air the hot pressure will be hard to control and gain as much as
6 psi during the race. I believe the reasons are the same for aviation
where if using air, the intense heat generated during touch down will
send the pressures soaring, adding to the risk of blowouts and wheel
damage.
John
Fogelsville, PA
Geoff Branch wrote:
>Charles and Boyles gas laws say that the composition of the gas doesn't
>matter.....provided it's pure gas....throw a little water vapor in and
the
>bets are off.
>
>One of the reasons nitrogen is used in aviation is that it comes from a
>bottle so is DRY.
>
>Of course it's more expensive than compressed air which is another
reason to
>use it the military and aviation bidness!!
>
>Geoff Branch
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