Standard pressure and temperature

Lawrence C Leung l.leung at juno.com
Wed Mar 21 19:12:48 EST 2001


I've skied at 12,000 ft (Taos, NM). Trust me you can breathe (just not
well). On any type of run, I could only go about 100 - 200 yards and then
HAD to stop, just to get oxygen. Too bad that they didn't sell it in
bottles there, 'cuz I would have bought up the venders stock just then.
Otherwise, totally awesome skiing!

LL (sea level) NY

On Wed, 21 Mar 2001 01:33:44 EST RubEric at aol.com writes:
>In a message dated 3/20/01 10:58:34 AM Pacific Standard Time, 
>audi at mediaone.net writes:
>
><<  >  This can make a big difference - at 100 degrees F and 10,000 
>feet
> > (altitude
> > >  of Leadville, CO, for instance), the density altitude is now 
>equivalent
> > to
> > >  about 15,000 feet, and the outside air pressure is only 15 
>inches of
> > >  mercury, which means we need THREE bar showing on the boost 
>gauge to get
> > >  sea level air pressure (1 bar) plus .5 bar boost (total 1.5 bar) 
>in the
> > >  manifold and thus sea level performance.
>
>No. You still need TWO bar on the boost guage to equal sea level 
>performance. 
> If the maximum you can get at sea level is 2 bar, you will get 
>proportionately less at altitude.
>
>The boost guage is absolute. At 18,000 feet the guage would read .5 
>bar (or 
>15 inches of mercury, or 500 millibars, or ~7psi).  If your 
>turbo/engine 
>combination is CAPABLE  of generating  15 lbs of boost (1 bar), your 
>guage 
>then would read 1.5 bar at max boost. To get 2 bar on the boost guage, 
>you 
>would need a turbo/engine combination capable of generating 22.5 lbs 
>of 
>boost. 
>
>(Note: A racing P-51 pulls about 120 inches of manifold pressure in 
>racing 
>trim. That is about FORTY FIVE lbs of boost!!!!!  Normal maximum boost 
>for 
>the P-51 in wartime trim was about 60 inches for take off.)
>
>
> 
> <<<can you even *breathe* at 0.5 bar???  Just barely.  In an 
>unpressurized 
>aircraft, a pilot must breath supplemental oxygen above 10,000 feet 
>but a 
>passenger is nor required to breath supplemental oxygen until 12,000.  
>People 
>do heavy work above 12,000 feet, however.  It does require some 
>acclimation 
>to avoid "altitude sickness".  The acclimation is to give the body 
>time to 
>generate additional red blood cells in order to extract the necessary 
>oxygen 
>from the lower pressure air with lower partial pressure of oxygen. 
>
>Atmospheric pressure is half of sea level pressure at about 18,000 
>feet.  
>There are other considerations of partial pressure of gases that are 
>involved 
>with being able to breathe not at issue with a turbocharged engine.
>
>
>  >>



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