"Ray" <bpracing@worldnet.att.net> wrote:
:>
: <snip>
:> I ignore elevation because elevation itself doesn't have an effect
:> on your performance. Where elevation does come into play is with the
:> air density - the higher you go, the less the "column of air" pushing
:> down on you weighs, and the less the air pressure. However, this is
:> nothing more than barometric pressure. This is why I ignore elevation
:> and base everything on weather readings (temp, humidity, barometric
:> pressure)
: <snip>
:> That said, in general, yes, you will run slower at higher elevations.
:> :-)---- Jon Steiger ------ jon@dakota-truck.net or
: Very well put and excellent examples, Jon. I hadn't really thought about
: it to that extent as I have my weather gauges and that's all I go by. The
: higher the track elevation, the lower the barometric pressure you will
: generally see so you can expect your performance to suffer.
Yep, that is true.
: At exceptionally high elevations, however, wouldn't you expect to have less
: oxygen content as well? I'm thinking of Bandimere in CO which is, I
: believe, over a mile high.
Yes. In fact, this is the main reason why performance suffers.
As the air pressure decreases, the density of oxygen molecules in the
air decreases, and for a given volume of air, you will have less
oxygen molecules. Of course, oxygen is a primary requirement for
combustion, so the less oxygen present, the less fuel you can burn
and the less power to be made. Wether talking about barometric pressure
due to weather systems or altitude, its all about those little oxygen
molecules. :-)
Turbo and supercharged cars aren't as sensitive to these changes
because they can compensate for the reduced pressure, to a certain
extent, because they make their own atmosphere... in a sense. :-)
Turbochargers are fairly common on piston powered aircraft which cruise
at high altitudes for this very reason.
---Jon-
.---- Jon Steiger ------ jon@dakota-truck.net or jon@jonsteiger.com -----. | I'm the: AOPA, DoD, EAA, NMA, NRA, SPA, USUA. Rec & UL Pilot - SEL | | '70 Barracuda, '92 Ram 4x4, '96 Dakota, '96 Intruder 1400, '96 FireFly | `----------------------------------------- http://www.jonsteiger.com ----'
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