Question about being unpressurized at higher (Class A) altitudes

[es330td]

My father has a C182 in which I have been to about 10K ft MSL. I am
currently working on my license and am considering building a Velocity
or Aerocanard, both of which have ceilings up into Class A airspace,
one as high as FL250. (Before anyone cautions me about building one
of these, I know two people with Velocities and a local builder who
has built multiple canard aircraft. I will have lots of support and
will have logged PIC time in one long before mine is built.) While I
know that oxygen is required at altitude, what is the effect of the
lower pressure on pilot and passengers? I am doing this in part for
the purpose of transporting myself and family to visit friends and
relatives and am curious about the effect on my two children,
currently 3 and 5, and whether this will make them less pleasant to
fly with.

TIA

[Robert M. Gary]

For a variety of reasons pilots usually don't fly in the flight levels
unless there is some clear advantage to doing so. This usually
involves trying to top weather or pick up a strong tailwind. At flight
levels you'll need an O2 mask (not a cannula). I'm not sure if that
will work for a 3 or 5 year old. However, realistically, you are
probably unlikely to ever want/need to actually fly that high. Being
able to fly comfortably above 12K is very advantageous, being able to
fly above 18K is much less so.

-Robert

[Dudley Henriques[_2_]]

es330td wrote:
> My father has a C182 in which I have been to about 10K ft MSL. I am
> currently working on my license and am considering building a Velocity
> or Aerocanard, both of which have ceilings up into Class A airspace,
> one as high as FL250. (Before anyone cautions me about building one
> of these, I know two people with Velocities and a local builder who
> has built multiple canard aircraft. I will have lots of support and
> will have logged PIC time in one long before mine is built.) While I
> know that oxygen is required at altitude, what is the effect of the
> lower pressure on pilot and passengers? I am doing this in part for
> the purpose of transporting myself and family to visit friends and
> relatives and am curious about the effect on my two children,
> currently 3 and 5, and whether this will make them less pleasant to
> fly with.
>
> TIA
>
I'd give this a lot of thought before doing it. You can of course fly an
unpressurized aircraft at altitudes requiring O2 if the aircraft is
capable and you have the correct O2 system installed, but I'd be
particularly careful with children this young. Mask feeding is dependent
on a careful fit of the mask to the face and any movement of the mask
could cause insufficient O2 flow to the user.
To be blunt, it's doable, but would require constant monitoring of
children this young.
If ity was me, I'd not consider flying at these altitudes with young
children. There are just too many possibilities for problems, and a
young child deprived of oxygen caused by moving the mask could easily be
come something you wouldn't want to deal with I'm sure.
I've flown high altitude many times in unpressurized prop fighters and
even I had a serious incident in a P51 Mustang caused by an improper O2
feed.
Be careful.

--
Dudley Henriques

[John[_1_]]

On Sep 13, 9:47 am, es330td > wrote:
> My father has a C182 in which I have been to about 10K ft MSL. I am
> currently working on my license and am considering building a Velocity
> or Aerocanard, both of which have ceilings up into Class A airspace,
> one as high as FL250. (Before anyone cautions me about building one
> of these, I know two people with Velocities and a local builder who
> has built multiple canard aircraft. I will have lots of support and
> will have logged PIC time in one long before mine is built.) While I
> know that oxygen is required at altitude, what is the effect of the
> lower pressure on pilot and passengers? I am doing this in part for
> the purpose of transporting myself and family to visit friends and
> relatives and am curious about the effect on my two children,
> currently 3 and 5, and whether this will make them less pleasant to
> fly with.
>
> TIA

I am not at all sure if this is accurate, but Ernie Gann in his book
"Fate is the Hunter" described an episode where he was carrying troops
in the back and they were getting a bit out of hand. He climbed and
the reduced oxygen resulted in a cabin of slumbering souls. Two
caveats: I am not sure . . . but alcohol may have played a role in
the story and . . . my experience with high altitude unpressurized
flight is that by the time I get back to the ground, I have a headache
that would make most migranes blush. Obviously, not everyone has the
same experience.

Take care . . .

John

[Jim Stewart]

John wrote:

> I am not at all sure if this is accurate, but Ernie Gann in his book
> "Fate is the Hunter" described an episode where he was carrying troops
> in the back and they were getting a bit out of hand. He climbed and
> the reduced oxygen resulted in a cabin of slumbering souls. Two
> caveats: I am not sure . . . but alcohol may have played a role in
> the story and . . .


I've read "Fate is the Hunter" several times and I
don't remember that story. If you can think of
another Gann book that it might be in, I'd sure
like to read it.

[es330td]

On Sep 13, 9:47 am, es330td > wrote:
> My father has a C182 in which I have been to about 10K ft MSL. I am
> currently working on my license and am considering building a Velocity
> or Aerocanard, both of which have ceilings up into Class A airspace,
> one as high as FL250. (Before anyone cautions me about building one
> of these, I know two people with Velocities and a local builder who
> has built multiple canard aircraft. I will have lots of support and
> will have logged PIC time in one long before mine is built.) While I
> know that oxygen is required at altitude, what is the effect of the
> lower pressure on pilot and passengers? I am doing this in part for
> the purpose of transporting myself and family to visit friends and
> relatives and am curious about the effect on my two children,
> currently 3 and 5, and whether this will make them less pleasant to
> fly with.
>
> TIA

Thanks for everyone's responses. I am somewhat lacking in knowledge
at this point; I know my desires but not the specifics of
implementation. By the time this plane is built the kids will
probably be 5 or more years older but if my friend with the Velocity
lets me rent it it may be an issue sooner. I know that planes gain
efficiency at altitude but I don't know how high one must go to
realize those gains. I just assumed that with a service ceiling over
FL200 that pilots would generally want to go there. My CFI flies King
Air 350's and Citation Jets for hire so I am used to hearing about his
experiences, something very different than the flying I will be doing.

[Gig 601XL Builder]

es330td wrote:

> Thanks for everyone's responses. I am somewhat lacking in knowledge
> at this point; I know my desires but not the specifics of
> implementation. By the time this plane is built the kids will
> probably be 5 or more years older but if my friend with the Velocity
> lets me rent it it may be an issue sooner.

He can't legally rent you his Velocity.


> I know that planes gain
> efficiency at altitude but I don't know how high one must go to
> realize those gains. I just assumed that with a service ceiling over
> FL200 that pilots would generally want to go there. My CFI flies King
> Air 350's and Citation Jets for hire so I am used to hearing about his
> experiences, something very different than the flying I will be doing.

Ask you CFI about it. While the Velocity is a hell of a plane it isn't a
Citation or King Air.

[Al G[_1_]]

"Bob Moore" > wrote in message
46.128...
> es330td wrote
>> I know that planes gain efficiency at altitude but
>> I don't know how high one must go to realize those gains.
>
> Very true with jet engines....not so much with piston engines.
> If you aren't turbocharged, you'll never make Class A airspace.
>
> Bob Moore
>
>
Gawd, don't let the glider folks hear you say that.

Al G

[Robert M. Gary]

On Sep 13, 9:59 am, John > wrote:
> On Sep 13, 9:47 am, es330td > wrote:
>
> > My father has a C182 in which I have been to about 10K ft MSL. I am
> > currently working on my license and am considering building a Velocity
> > or Aerocanard, both of which have ceilings up into Class A airspace,
> > one as high as FL250. (Before anyone cautions me about building one
> > of these, I know two people with Velocities and a local builder who
> > has built multiple canard aircraft. I will have lots of support and
> > will have logged PIC time in one long before mine is built.) While I
> > know that oxygen is required at altitude, what is the effect of the
> > lower pressure on pilot and passengers? I am doing this in part for
> > the purpose of transporting myself and family to visit friends and
> > relatives and am curious about the effect on my two children,
> > currently 3 and 5, and whether this will make them less pleasant to
> > fly with.
>
> > TIA
>
> I am not at all sure if this is accurate, but Ernie Gann in his book
> "Fate is the Hunter" described an episode where he was carrying troops
> in the back and they were getting a bit out of hand. He climbed and
> the reduced oxygen resulted in a cabin of slumbering souls. Two
> caveats: I am not sure . . . but alcohol may have played a role in
> the story and . . . my experience with high altitude unpressurized
> flight is that by the time I get back to the ground, I have a headache
> that would make most migranes blush. Obviously, not everyone has the
> same experience.

I've done this with my boys. However, I usually raise them to about
12K, not 22K to make them sleep. I've also spoken with C5 pilots who
do the same fro the troops in the back when they get worked up.
However, we're talking about 12Kish, not 22K.

_Robert

[Robert M. Gary]

On Sep 13, 2:12 pm, "Al G" > wrote:
> "Bob Moore" > wrote in message
>
> 46.128...> es330td wrote
> >> I know that planes gain efficiency at altitude but
> >> I don't know how high one must go to realize those gains.
>
> > Very true with jet engines....not so much with piston engines.
> > If you aren't turbocharged, you'll never make Class A airspace.
>
> > Bob Moore
>
> Gawd, don't let the glider folks hear you say that.

Piston powered glider??

[Kloudy via AviationKB.com]

Al G wrote:
> Gawd, don't let the glider folks hear you say that.
>
> Al G

Hey!

I heard that...

--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums.aspx/aviation/200709/1

[es330td]

On Sep 13, 2:40 pm, "Gig 601XL Builder" <wrDOTgiaconaATsuddenlink.net>
wrote:
> es330td wrote:
>
> He can't legally rent you his Velocity.
>
I didn't know that.

[es330td]

On Sep 13, 4:24 pm, Bob Moore > wrote:
> es330td wrote
>
> > I know that planes gain efficiency at altitude but
> > I don't know how high one must go to realize those gains.
>
> Very true with jet engines....not so much with piston engines.
> If you aren't turbocharged, you'll never make Class A airspace.
>
> Bob Moore

The specs on the Aerocanard FG state that with an LIO-360 engine the
service ceiling is FL250. Not that I would be trying to make Class A
but according to the definition of service ceiling shouldn't this
plane be able to at least make FL180 and then some?

[Newps]

es330td wrote:


By the time this plane is built the kids will
> probably be 5 or more years older




No way you get it done in less than 10 years. I've seen it countless times.


My CFI flies King
> Air 350's and Citation Jets for hire so I am used to hearing about his
> experiences, something very different than the flying I will be doing.


You won't be going that high.

[Dan Luke[_2_]]

"es330td" wrote:

>
> The specs on the Aerocanard FG state that with an LIO-360 engine the
> service ceiling is FL250. Not that I would be trying to make Class A
> but according to the definition of service ceiling shouldn't this
> plane be able to at least make FL180 and then some?

Yes, but you probably wouldn't want to do it.

It would probably take a long time to climb that high in a naturally-aspirated
airplane, then there's the bother and discomfort of wearing a mask once you
got there.

I think you'll find the low teens is as high as you'll want to go in the
airplane you're proposing.

--
Dan
T-182T at BFM

[Morgans[_2_]]

"John" > wrote

> I am not at all sure if this is accurate, but Ernie Gann in his book
> "Fate is the Hunter" described an episode where he was carrying troops
> in the back and they were getting a bit out of hand. He climbed and
> the reduced oxygen resulted in a cabin of slumbering souls.

In airliners, all you have to do is change the cabin altitude pressure
setting, and you can do the same thing, and they do occasionally do this on
(especially on) oceanic red-eyes.

They don't have to go all that high to have a noticeable effect, but it does
make it easy for the flight attendants.
--
Jim in NC

[Andrew Sarangan]

On Sep 13, 2:34 pm, es330td > wrote:
> On Sep 13, 9:47 am, es330td > wrote:
>
> > My father has a C182 in which I have been to about 10K ft MSL. I am
> > currently working on my license and am considering building a Velocity
> > or Aerocanard, both of which have ceilings up into Class A airspace,
> > one as high as FL250. (Before anyone cautions me about building one
> > of these, I know two people with Velocities and a local builder who
> > has built multiple canard aircraft. I will have lots of support and
> > will have logged PIC time in one long before mine is built.) While I
> > know that oxygen is required at altitude, what is the effect of the
> > lower pressure on pilot and passengers? I am doing this in part for
> > the purpose of transporting myself and family to visit friends and
> > relatives and am curious about the effect on my two children,
> > currently 3 and 5, and whether this will make them less pleasant to
> > fly with.
>
> > TIA
>
> Thanks for everyone's responses. I am somewhat lacking in knowledge
> at this point; I know my desires but not the specifics of
> implementation. By the time this plane is built the kids will
> probably be 5 or more years older but if my friend with the Velocity
> lets me rent it it may be an issue sooner. I know that planes gain
> efficiency at altitude but I don't know how high one must go to
> realize those gains. I just assumed that with a service ceiling over
> FL200 that pilots would generally want to go there. My CFI flies King
> Air 350's and Citation Jets for hire so I am used to hearing about his
> experiences, something very different than the flying I will be doing.

The airframe gains efficiency with altitude, but the engine loses
efficiency with altitude. So there is an optimum altitude where you
get the best performance. This happens to be around 8000 ft for
normally aspirated engines. Turbo charging will push this to a higher
altitude.

I don't know where you got the information that Velocity has a service
ceiling of 25k. It is not the airframe that determines the service
ceiling as much as the engine choice.

[Matt Barrow[_4_]]

"Andrew Sarangan" > wrote in message
ups.com...

> The airframe gains efficiency with altitude, but the engine loses
> efficiency with altitude.

How does the airframe "gain efficiency" at altitude, aside from generating
less drag?

[es330td]

On Sep 13, 10:51 pm, "Marc J. Zeitlin" >
wrote:
> es330td wrote:
> > ..... While I know that oxygen is required at altitude, what is the
> > effect of the lower pressure on pilot and passengers? I am doing
> > this in part for the purpose of transporting myself and family to
> > visit friends and relatives and am curious about the effect on my
> > two children, currently 3 and 5, and whether this will make them
> > less pleasant to fly with.
>
> You've gotten a number of reasonable answers from folks that don't fly
> canard aircraft of this type - here's some info from someone that
> does. I have a COZY MKIV with an O-360-A2A 180 HP engine. I
> regularly fly at 13.5K ft., and have been to 15.5K ft. once. The
> reasons to go that high are to get above the haze layer, get above a
> cloud layer, see distant T-storm buildups, miss mountains, and get
> into more favorable winds to get better fuel economy.
>
> I normally fly around 7.5K ft - 10.5K ft., as the plane is fastest
> down there (at 60-75% power) and I don't need O2. I'll go higher for
> short periods of time for ground clearance when crossing the Rockies
> or Sierras, or when flying over northern AZ where the ground's at 7.5K ft.
>
> Above 18K ft., you'd have to wear a mask, rather than a cannula. The
> Cannula is not particularly intrusive, but masks are. Plus, you'd
> have to be on an IFR flight plan (and obviously be IR). There are a
> few canard folks that regularly fly in the low 20's, but only when the
> winds are favorable (generally going east).
>
> At any rate, assuming that you've got O2 on yourself and your family,
> up to 18K with cannulae, you're fine (get a pulse Oximeter so that you
> can measure your blood's saturated O2 levels to make sure you're
> actually getting the O2). The lower pressure has essentially no
> effect, if you've got O2.
>
> Keeping cannulae on little kids would be difficult, but as you state,
> it'll be a few years (not 10, as proposed - it took 7 for me to build
> my COZY, but I know many folks that have built canard aircraft in 2-5
> years) before they're actually flying. In fact, per 91.211, they
> don't HAVE to have O2 unless you're above 15K ft., so you can fly up
> to there, use O2 for yourself, and let them nap in the back without O2.
>
> If you're seriously considering a canard aircraft, I suggest that you
> join the COZY mailing list and/or the yahoo canard-aviators mailing
> list, to get information directly from hundreds of folks building and
> flying canard aircraft. There are only a few Aerocanards flying (less
> than 15 - maybe less than 10), and there's no specific list for them.
>
> --
> Marc J. Zeitlin
> http://www.cozybuilders.org/
> Copyright (c) 2007

Thanks for this response. I am serious about owning a canard; I can't
find a manufactured plane that will give me the range and speed to
make the cross country flying worth doing at a cost I can afford. I
am leaning toward the Aerocanard as it is kit rather than plans built
so it should get flying sooner rather than later.

To all: This discussion has been very educational. I haven't learned
yet at what altitude a plane gives maximum performance at cruise power
though from these responses it appears that under FL100 is expected
and preferred. I guess I'll leave Class A to the turbine powered
airplanes.

[Thomas Borchert]

Es330td,

> I guess I'll leave Class A to the turbine powered
> airplanes.
>

Not to worry, there are plenty of countries with Class A way below
FL100.

--
Thomas Borchert (EDDH)

[Morgans[_2_]]

"es330td" <> wrote
>
> To all: This discussion has been very educational. I haven't learned
> yet at what altitude a plane gives maximum performance at cruise power
> though from these responses it appears that under FL100 is expected
> and preferred. I guess I'll leave Class A to the turbine powered
> airplanes.

At low altitudes, you can get the engine to produce a lot of power, and go
pretty fast. Unfortunately, you burn a LOT of fuel.

You go up to 7 or 8 thousand feet, and the engine does not produce much
power; perhaps 60 percent, with the throttle wide open. But, since there is
a LOT less drag, (as compared to low altitudes) you can go a lot faster than
60 percent at the lower altitudes.

So, you climb up to 8 thousand feet, and go as fast or faster than you were
going at sea level burning almost twice as much fuel.

There is a trade off between altitude and speed, and each design airplane is
going to have its ideal altitude, to go the fastest, with the least fuel
burn. It all depends on the different types of drag, and how much that
design's drag is reduced, and the power output of the engine.

This is a general overview of the concept that you are trying to grasp, I
hope. Apologies if it is stuff you know already.
--
Jim in NC

[Mxsmanic]

Morgans writes:

> In airliners, all you have to do is change the cabin altitude pressure
> setting, and you can do the same thing, and they do occasionally do this on
> (especially on) oceanic red-eyes.

You can only go to 8000 in (most) airliners.

> They don't have to go all that high to have a noticeable effect, but it does
> make it easy for the flight attendants.

Only if the FAs are wearing oxygen masks.

[Mxsmanic]

Matt Barrow writes:

> How does the airframe "gain efficiency" at altitude, aside from generating
> less drag?

Less drag is a big advantage. The higher an aircraft flies, the more easily
you can move it forward. Ultimately, you end up in outer space, with no air,
and then you don't need any energy at all to keep it moving forward (the
principle behind hypersonic aircraft). This is one reason why the SR-71 is
very efficient in cruise. It's also a reason why jets fly high even though
the engines produce less power at high altitudes--the power required to
maintain a given speed decreases faster than the power provided by the
engines, as altitude increases (within certain limits).

[Andrew Sarangan]

On Sep 13, 10:41 pm, "Matt Barrow" >
wrote:
> "Andrew Sarangan" > wrote in message
>
> ups.com...
>
> > The airframe gains efficiency with altitude, but the engine loses
> > efficiency with altitude.
>
> How does the airframe "gain efficiency" at altitude, aside from generating
> less drag?

It gains efficiency because you can move faster for the same engine
power. If you disregard drag, then you might as well disregard the
engine too because thrust = drag at level unaccelerated flight.

[Bertie the Bunyip[_19_]]

Mxsmanic > wrote in
:

> Matt Barrow writes:
>
>> How does the airframe "gain efficiency" at altitude, aside from
>> generating less drag?
>
> Less drag is a big advantage. The higher an aircraft flies, the more
> easily you can move it forward. Ultimately, you end up in outer
> space, with no air, and then you don't need any energy at all to keep
> it moving forward (the principle behind hypersonic aircraft). This is
> one reason why the SR-71 is very efficient in cruise. It's also a
> reason why jets fly high even though the engines produce less power at
> high altitudes--the power required to maintain a given speed decreases
> faster than the power provided by the engines, as altitude increases
> (within certain limits).
>

Wrong again, bozo


Bertie

[Bertie the Bunyip[_19_]]

es330td > wrote in news:1189691258.415403.151350@
50g2000hsm.googlegroups.com:

> My father has a C182 in which I have been to about 10K ft MSL. I am
> currently working on my license and am considering building a Velocity
> or Aerocanard, both of which have ceilings up into Class A airspace,
> one as high as FL250. (Before anyone cautions me about building one
> of these, I know two people with Velocities and a local builder who
> has built multiple canard aircraft. I will have lots of support and
> will have logged PIC time in one long before mine is built.) While I
> know that oxygen is required at altitude, what is the effect of the
> lower pressure on pilot and passengers? I am doing this in part for
> the purpose of transporting myself and family to visit friends and
> relatives and am curious about the effect on my two children,
> currently 3 and 5, and whether this will make them less pleasant to
> fly with.
>
> TIA
>
>
A, your kids will be teenagers at least by the time oyu get the thing done
(ask me how I know this)
B, pax on O2 are usually not happy pax.. It's a pain in the ass, really.
C. You'll probably almost never go up to altitudes where O2 is required for
several reasons unless you're the exception who proves the rule..

Bertie

[Matt Barrow[_4_]]

"Andrew Sarangan" > wrote in message
oups.com...
> On Sep 13, 10:41 pm, "Matt Barrow" >
> wrote:
>> "Andrew Sarangan" > wrote in message
>>
>> ups.com...
>>
>> > The airframe gains efficiency with altitude, but the engine loses
>> > efficiency with altitude.
>>
>> How does the airframe "gain efficiency" at altitude, aside from
>> generating
>> less drag?
>
> It gains efficiency because you can move faster for the same engine
> power.

That's not the airframe gainning efficeincy, that's called a reduction in
drag.

> If you disregard drag, then you might as well disregard the
> engine too because thrust = drag at level unaccelerated flight.

I'll have to dig through my library of physics books to 'splain that one.
:~)

The engine loses the _ability_ to generate power, but that has noting to do
with your T=D formula.

Think: turbocharging.

The airframe is static, so there's no gain or loss in efficiency.

Now, if you have a wing like the F-14, that could be considered as a whole
different story.

[John[_1_]]

On Sep 13, 1:18 pm, Jim Stewart > wrote:
> John wrote:
> > I am not at all sure if this is accurate, but Ernie Gann in his book
> > "Fate is the Hunter" described an episode where he was carrying troops
> > in the back and they were getting a bit out of hand. He climbed and
> > the reduced oxygen resulted in a cabin of slumbering souls. Two
> > caveats: I am not sure . . . but alcohol may have played a role in
> > the story and . . .
>
> I've read "Fate is the Hunter" several times and I
> don't remember that story. If you can think of
> another Gann book that it might be in, I'd sure
> like to read it.

OK Jim, lemme see. . . I dont think it is in the High and Mighty. . .
so try Gentlemen of Adventure, or Band of Brothers, or In the Company
of Eagles or maybe Hostage to Fortune which is Gann's actual
biography.

Hmmm . . . might be a good excuse to re-read his books. Although I
read the 1986 reprint of Fate is the Hunter had several episodes
editted out that appeared in the original 1961 edition. I do remember
when i re read it last, I was left kinda wondering what happened to
the book.

Take care . . .

John

[es330td]

On Sep 13, 8:48 pm, Andrew Sarangan > wrote:
>
> I don't know where you got the information that Velocity has a service
> ceiling of 25k. It is not the airframe that determines the service
> ceiling as much as the engine choice.- Hide quoted text -
>
The Velocity won't go that high; according to the specs on their
website the RG Velocities top out about FL200. The Cozy based
Aerocanard will go to FL250, according to http://www.aerocad.com/Performance.htm.
While they could be completely full of it, I don't see too many people
trusting their life and paying over $30K for a homebuilt kit to a
company that lies about its planes' performance numbers.

[Gatt]

"es330td" > wrote in message
ups.com...

> will have logged PIC time in one long before mine is built.) While I
> know that oxygen is required at altitude, what is the effect of the
> lower pressure on pilot and passengers?

Sinus blockages, intestinal gas and particularly poor dental work (air
behind the fillings, I guess) can be extremely uncomfortable or
excruciating.