Things to remember in very hot weather

In article ,
Michael Ash wrote:

In rec.aviation.student Steve Hix wrote:
In article ,
Michael Ash wrote:

At the risk of turning this thread into something useful,

Heaven forfend!

does anyone have
any recommendations as to when it's a good idea to give oxygen to
passengers? I'm not talking about the legal requirements, but just when
it's the smart thing to do. For example, as the pilot I like to start my
oxygen at about 10,000ft even though it's not required until quite a bit
higher. But then again, it doesn't really matter too much if my passengers
have mildly impaired judgement during the flight, even though I'd really
want to avoid that myself.

This is really an academic question since I don't plan to take anybody
that high to begin with, but I'm curious.

Depends on the person, really.

Good point!

I have a friend who begins to exhibit severe headaches and some cyanosis
(his lips and fingernails start to go purple) above about 8000'. He's
been warned to be very cautious about higher elevations, as he's
probably a prime candidate for mountain sickness. So much for his dreams
of trekking the Himalayas.

That's a bit extreme, but it's worth watching for if you have a
passenger who's never been at altitude before.

Heavy smokers, or anyone with compromised cardiopulmonary function
should be cautious, probably.

Do I correctly understand that you would be happy with monitoring for
symptoms during the flight and making the decision then? I don't want to
do this as the pilot, but only because judgement is one of the first
things to go. For passengers this seems to be entirely reasonable.

For passengers, mostly.

I've done some testing previously, and have determined that up to at
least 11,500' there're no noticeable effects for me. (Modulo fatigue,
recovery from illness, etc.) The initial checks I did with another
pilot, my instructor at the time, and he brought oxygen along.

Over the past several decades, I've been tested for VO2max, and I'm on
the high side of the population. I used to cycle competitively, which
was initially the reason to check, after that just curiousity.

Has to be careful choice of grandparents; I've lived essentially at sea
level for my whole life (California coastal, mostly).

My son smokes; him I'd want to check if we cross the Sierra Nevada or
points east.

In article PTV9k.157$K%2.34@trnddc02, "Mike"
wrote:

"Mxsmanic" wrote in message
...
Mike writes:

The "real thing" doesn't necessarily require a compressor.

So how does it work?

Some older planes had a non-compressor based system that required water. I
assume it was some sort of evaporative cooling setup. I lived in El Paso,
Texas where the temps routinely got above 43° C and I had an evaporative
cooler in my home that worked just fine.

You can also buy aftermarket systems that use ice.

There are also state-change systems that just need a heat source to
drive them, like Dometic kerosene refrigerators. Not very useful for
aircraft use, granted.

"Mxsmanic" wrote in message
...
muff528 writes:

I would extend that thought to include *any* plane :-)

High-performance aircraft that can fly well above mountain ranges
shouldn't be
a problem.

Well, wouldn't that be considered "avoiding the mountains"?

TP

muff528 writes:

Well, wouldn't that be considered "avoiding the mountains"?

Potentially, yes.

On Jun 29, 7:23 pm, Steve Hix
wrote:
In article PTV9k.157$K%2.34@trnddc02, "Mike"
wrote:

"Mxsmanic" wrote in message
.. .
Mike writes:

The "real thing" doesn't necessarily require a compressor.

So how does it work?

Some older planes had a non-compressor based system that required water. I
assume it was some sort of evaporative cooling setup. I lived in El Paso,
Texas where the temps routinely got above 43° C and I had an evaporative
cooler in my home that worked just fine.

You can also buy aftermarket systems that use ice.

There are also state-change systems that just need a heat source to
drive them, like Dometic kerosene refrigerators. Not very useful for
aircraft use, granted.

Turbine engined airplanes don't have AC compressors. They bleed
some compressed air from the compressor stage of the engine, run that
through an exchanger to cool it, then drop its pressure, which lowers
its temperature a whole bunch. Mixing this really cold air with hot
bleed air provides whatever temperature the pilot wants.
A piston engine with a larger turbocharger could use some of
the same effect but it would be less effective since the pressures are
lower.

Dan

wrote in
:

On Jun 29, 7:23 pm, Steve Hix
wrote:
In article PTV9k.157$K%2.34@trnddc02, "Mike"
wrote:

"Mxsmanic" wrote in message
.. .
Mike writes:

The "real thing" doesn't necessarily require a compressor.

So how does it work?

Some older planes had a non-compressor based system that required
water.
I
assume it was some sort of evaporative cooling setup. I lived in
El Pas
o,
Texas where the temps routinely got above 43° C and I had an
evaporati
ve
cooler in my home that worked just fine.

You can also buy aftermarket systems that use ice.

There are also state-change systems that just need a heat source to
drive them, like Dometic kerosene refrigerators. Not very useful for
aircraft use, granted.

Turbine engined airplanes don't have AC compressors. They bleed
some compressed air from the compressor stage of the engine, run that
through an exchanger to cool it, then drop its pressure, which lowers
its temperature a whole bunch. Mixing this really cold air with hot
bleed air provides whatever temperature the pilot wants.
A piston engine with a larger turbocharger could use some of
the same effect but it would be less effective since the pressures are
lower.


Actually, some turbines do use compressers, like the old RR Dart, for
instance (they call it a spupercharger, it's a rootes type compressor)

The 787 is going back to them in an effort to get away from the problem
of cabin fumes...


Bertie

In article RgX9k.272$bn3.204@trnddc07,
"muff528" wrote:

"Mxsmanic" wrote in message
...
muff528 writes:

I would extend that thought to include *any* plane :-)

High-performance aircraft that can fly well above mountain ranges
shouldn't be
a problem.

Well, wouldn't that be considered "avoiding the mountains"?

Only for those thinking in 3D terms.

Nomen Nescio wrote in
:

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From: Mxsmanic

I know, but I prefer not to wait until the law requires it to take
precautions. Some people show signs of hypoxia at half that altitude.
Why take the risk?


Un-F**kin'- Believable!

An I the only one picturing the dip****, sitting in front of his
computer, shoving a tube up his nose at an "altimeter" reading
of 7000 ft?




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No, you are not alone in your picture. You just left out that he has the
other end up his ass so he can fart and pretent he is getting O2.

wrote in message
...
On Jun 29, 7:23 pm, Steve Hix
wrote:
In article PTV9k.157$K%2.34@trnddc02, "Mike"
wrote

There are also state-change systems that just need a heat source to
drive them, like Dometic kerosene refrigerators. Not very useful for
aircraft use, granted.

Turbine engined airplanes don't have AC compressors. They bleed
some compressed air from the compressor stage of the engine, run that
through an exchanger to cool it, then drop its pressure, which lowers
its temperature a whole bunch. Mixing this really cold air with hot
bleed air provides whatever temperature the pilot wants.
A piston engine with a larger turbocharger could use some of
the same effect but it would be less effective since the pressures are
lower.

Dan

Well...some turbine powered airplanes have AC compressors. The one I flew
had one, we used it to pre-cool the cabin and up to 18,000 feet. We also
used it as a de-humidifier when going into humid areas so the windshield
would not fog up.

--
*H. Allen Smith*
WACO - We are all here, because we are not all there.

On Sun, 29 Jun 2008 21:16:33 -0700 (PDT),
wrote:

On Jun 29, 7:23 pm, Steve Hix
wrote:
In article PTV9k.157$K%2.34@trnddc02, "Mike"
wrote:

"Mxsmanic" wrote in message
.. .
Mike writes:

The "real thing" doesn't necessarily require a compressor.

So how does it work?

Some older planes had a non-compressor based system that required water. I
assume it was some sort of evaporative cooling setup. I lived in El Paso,
Texas where the temps routinely got above 43° C and I had an evaporative
cooler in my home that worked just fine.

You can also buy aftermarket systems that use ice.

There are also state-change systems that just need a heat source to
drive them, like Dometic kerosene refrigerators. Not very useful for
aircraft use, granted.

Turbine engined airplanes don't have AC compressors. They bleed
some compressed air from the compressor stage of the engine, run that
through an exchanger to cool it, then drop its pressure, which lowers
its temperature a whole bunch. Mixing this really cold air with hot
bleed air provides whatever temperature the pilot wants.
A piston engine with a larger turbocharger could use some of
the same effect but it would be less effective since the pressures are
lower.

Or they can install a Keith style all-electric compressor rather than
the Malibu style compressor which is belt-driven off the engine next
to the alternator belts. Needs a beefy electrical system though, it
draws darn near 50 amps.