Looking for A-14 (or similar) pressure breathing diluter demand regulator

TW,

Not so. FL500 is the generally accepted altitude where pressurized suits are required and by FL620 your blood at body temperature boils.

I think you are mixing up pressurized breathing with pressurized suits which is needed above FL400. I've flown to FL280 with an Alps mask on a MH system and had no difficulties. I know pilots who pushed this limit to FL320 with a MH system and an unpressurized system but this is certainly not recommended. The A14 will allow you to pressure breath at FL400 and above and apparently even a short duration trip to FL500 is possible. I personally would not go above FL450.

If you recall the recent passing of Bob Harris you will note that he flew to FL490 with a redundant A14 system. Probably the best lesson learned from his flight was the importance of having a well secured mask. Apparently he had to limit his climb because he couldn't keep his mask on as the pressure increased! He did not have a pressure suit.

Jim
VVII

The A-14 system, so I thought, is not a true pressure-demand type required at greater altitudes, but is a diluter-demand pressure regulated system with manual pressure valving available(?) Not to be confused with "pulse-demand" EDS. If needed I have a diluter-demand mask with microphone that can be loaned to Keith for his adventure.

While a cup of blood (or water for that matter) will boil at that altitude, circulating blood in a semi-sealed body will likely not (look up "Myth, boiling blood"). Mouth saliva would freeze first. Amazingly, experts say the astronaut in "2001 a Space Odyssey" caught in open space could theoretically have survived his short exposure.

If there's one locally, take a "flight" in an altitude chamber to discover how you function under hypoxic conditions (or you can try breathing a mixture of N2 with air/O2 to get your blood sat to 90% and less).

The A-14 system, so I thought, is not a true pressure-demand type required at greater altitudes, but is a diluter-demand pressure regulated system with manual pressure valving available(?) Not to be confused with "pulse-demand" EDS. If needed I have a diluter-demand mask with microphone that can be loaned to Keith for his adventure.

While a cup of blood (or water for that matter) will boil at that altitude, circulating blood in a semi-sealed body will likely not (look up "Myth, boiling blood"). Mouth saliva would freeze first. Amazingly, experts say the astronaut in "2001 a Space Odyssey" caught in open space could theoretically have survived his short exposure.

If there's one locally, take a "flight" in an altitude chamber to discover how you function under hypoxic conditions (or you can try breathing a mixture of N2 with air/O2 to get your blood sat to 90% and less). "drunk" pilot: https://www.reddit.com/r/videos/comm...are_emergency/

The diluter-demand function of the A14, from what I have read, occurs below a certain altitude, 30,000' if I recall correctly. In this mode the mixing chamber mixes cabin air with O2 and the amount of O2 increases with altitude. Above this altitude it supplies 100% O2. The pressure breathing function is a separate function that has different dial settings for increasing altitudes. Here the pressure of the O2 supplied not the mixture to the mask increases. The markings on the A14 dial suggest 5 different pressures for settings of Safety, 41,000', 43,000', 45,000', & above 45,000'. Not sure why the 1st dial setting is marked Safety but it is the 1st position when the dial is turned off normal.

I've read the same about blood boiling. I think, as you have pointed out, they are referring to an uncontained and uncirculating liquid and meant to make a point about how low the pressure is. Articles I've read also use statements like "seems to boil" instead of boils. I guess the body can contain the vapor pressure sufficiently so it doesn't reach atmospheric pressure and really boil. Apparently the skin will expand and early experiments with dogs in space or a vacuum chamber discovered this. Saliva boiling on the tongue makes sense.

I do plan to get experience in a hypobaric chamber and am hoping they will let me use my own mask, regulator, and bottle however, I suspect this might be considered a liability for then to allow. I still plan to ask. What better way to test the performance of the system I intend to use at FL350-400!

On 12/19/2018 8:34 AM, wrote:
The diluter-demand function of the A14, from what I have read, occurs below
a certain altitude, 30,000' if I recall correctly. In this mode the mixing
chamber mixes cabin air with O2 and the amount of O2 increases with
altitude. Above this altitude it supplies 100% O2. The pressure breathing
function is a separate function that has different dial settings for
increasing altitudes. Here the pressure of the O2 supplied not the mixture
to the mask increases. The markings on the A14 dial suggest 5 different
pressures for settings of Safety, 41,000', 43,000', 45,000', & above
45,000'. Not sure why the 1st dial setting is marked Safety but it is the
1st position when the dial is turned off normal.

FWIW...
Everything I've read (inhaled, unavoidable pun) since the early 1970s -
primary source: "Soaring" mags" (multiple/excellent "near-first-hand"
articles/columns throughout '70s/'80s) - said the same thing(s). Nothing on
RAS to which I lend credibility (i.e. "hearsay" seriously discounted) has
contradicted any of the above, since my RAS-introduction/continuing-exposure
ca. '96.


I've read the same about blood boiling. I think, as you have pointed out,
they are referring to an uncontained and uncirculating liquid and meant to
make a point about how low the pressure is. Articles I've read also use
statements like "seems to boil" instead of boils. I guess the body can
contain the vapor pressure sufficiently so it doesn't reach atmospheric
pressure and really boil. Apparently the skin will expand and early
experiments with dogs in space or a vacuum chamber discovered this. Saliva
boiling on the tongue makes sense.

I do plan to get experience in a hypobaric chamber and am hoping they will
let me use my own mask, regulator, and bottle however, I suspect this might
be considered a liability for them to allow. I still plan to ask. What
better way to test the performance of the system I intend to use at
FL350-400!

That's "exactly" what the late Bill Ivans (ca. '92) told me he did in the
years after WW-II before setting the world-altitude soaring-record (42,100',
as I seem to recall; '52?) that Paul Bikle broke (1961); memory sez both were
set in Schweizer 1-23s. Excerpts of my tape-recorded interview with Ivans
about those years of his soaring can be found in the book "Exploring the Monster".

Kinda-sorta related, I also interviewed (several times) Dr. J. Kuettner
(credited with the "scientific discovery" of standing lee waves, & Lead
Investigator of the subsequent Sierra Wave Projects), about: wave; his
experiences in same; his involvement(s) in illuminating waves' atmospheric
physics; his perception of "existing knowledge" of high-altitude physiology in
the timeframe ~'35-'55; etc.

My takeaways from my brain-picking - and a "chamber ride" ca. early-'80s) -
were/remain several...

- humans are physiologically complex critters, and one size definitely does
NOT fit all; almost certainly YMWV
- any "cast in concrete" safety claims regarding "high-altitude (say 35k'),
unpressurized-cockpit, supplementally-O2-assisted" flight beyond "It's
definitely life-threateningly risky," are likely misleading/inaccurate. "Back
then," high-altitude human physiology was FAR from being "pigeon-holed by
science" in "absolute safety" terms, and in a related vein,
"personally-derived high-altitude limits" seemed to be the accepted norm, at
least among the Sierra Wave Project participants. (Anecdotes below...)

Bill Ivans couldn't remember exactly how high he'd been taken in his chamber
ride, but "definitely" above 40k' (possibly 46k'). Without digging into
ancient notes, I can't remember how-high he set his personal limits prior to
his record-setting altitude flight, but I DO remember him chuckling that the
flight completely satisfied his "altitude curiosity!" I took that to mean he
felt he'd no continuing need to soar "near the physiological edge" going
forward. His job prevented him from piloting during the Sierra Wave Projects,
and I don't know if he was sounded out about doing so or not, but had he been
able, my long-after-the-fact guess was he might've declined.

The long-standing 2-seater world-soaring-altitude/gain flight of ~42k' set in
a Pratt-Read by Larry Edgar and Hal Klieforth (broken by Einar Enevoldsen and
the late Steve Fossett, I believe), had been intended to go no higher than
40k', the nominal limit the Sierra Wave Project soaring participants
pre-selected as their safety-limit for physiological reasons. The extra height
was due solely to the search time required to find descending air, once the
crew had decided "enough for today."

None of the Sierra Wave Project pilots could remember, or admitted to, any
"serious physiologic issues" on/after any of their high-altitude forays
(intestinal gas and cold temperatures notwithstanding). They all practiced
"best practices" before/during each flight, e.g. dietary choices, sleep
practices (not always hewed to, per Dr. K., commonly becuzza the need to
change-out batteries post-flight during a spell of more-or-less-daily standing
waves good for research), pre-breathing 100% O2, etc.

My sense is much of the "high-altitude-physiological-related" institutional
knowledge within the general sport-soaring world (U.S. anyway) has been
gradually lessened/lost due to the passage of time/aging/decreasing
availability of high-altitude chamber access for civilians/etc., to be
"commonly replaced" by a generation of pilots having distinctly different
norms for acceptable risk than the WW-II and immediately-following generations.

Insofar as deciding to take up a voluntary sporting activity (soaring, in this
case), some level of general ignorance is normally the beginning state.
Sometimes (often?) this natural ignorance is expressed in
needlessly/misguidingly stated maxims that quite simply are incorrect. This -
IMHO - is fairly common regarding high-altitude soaring flight...which is
definitely increasingly-seriously risky with increasing altitude, but those
risks are "adequately comprehensible and systematically-addressable," as
(thinks I) the history of post-WW-II high altitude soaring in the U.S. well
documents.

Personally, have at it and may good fortune accompany your preparations!

Bob W.

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Wow, thats quite some history Bob! I need to read up on wave history a lot more! Did you ever track any of the flights from up in Cowley, Alberta at the so called Diamond Mine? I had my 1st wave flight there about 9 years ago and I was hooked! I also learned a few new acronyms from you-FWIW and YMWV I could decipher but RAS? Silent Leader? Appreciate all your comments and I do look forward to a chamber ride before committing to anything above FL300! This is purely a recreational pursuit and one of several gliding challenges for me but it's definitely not to be taken lightly as my two favorite aviation sayings remind me......1) takeoffs are optional but landings are mandatory &...... 2) I'd rather be on the ground wishing I was in the air than (very high) in air wishing I was on the ground!

Jim
VVII

FWIW.....for what it's worth
YMMV.....your mileage (situation) may vary
RAS......recreational aviation....Soaring...(this forum where you're posting...)

Got the 1st two. RAS, of course-too obvious!

Jim
VVII

On 12/19/2018 3:05 PM, wrote:
Wow, that's quite some history Bob! I need to read up on wave history a lot
more! Did you ever track any of the flights from up in Cowley, Alberta at
the so called Diamond Mine? I had my 1st wave flight there about 9 years
ago and I was hooked! Snip...

The only "tracking" of which I'm aware related to Cowley wave soaring is the
book "Stalking the Mountain Wave" by Ursula Weise. My (autographed!) 2nd
edition copy has a 1997 copyright. I've never been to Cowley. In fact, the
only time I've been to Canada (with a friend to purchase an L13 some years ago
for a 3rd party), U.S. Customs didn't want to readmit us...so I've been
reluctant to leave the country ever since, eh? (True tale!)

Bob W.

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Yes, I met Ursula. She's married to Tony Burton an active CuNim pilot. I have the book as well but mine is not autographed! Cowley is THE wave destination in Canada.

Wonder if that L-13 you picked up was from CuNim? They sold one to Lee Cook I think flying out of Crystal. ISK if I'm not mistaken. I trained in that ship and I heard it got written off not long after it arrived in CA. Most of the L13s were grounded soon after that. Great 2-place workhorse.

Jim
VVII