3000 and 6000 feet.

[PeterSwinkels]

Here's a nitpick:

The comic seems to imply that you can breathe the air up to altitude of 3000 feet without extra oxygen (to prevent altitude sickness I assume) and up to 6000 feet with extra oxygen. I think the word "feet" needs to replaced by "meters" here... 3000 feet is aprox. 1 km, and if I am correct, people can breathe air up to an altitude of 3 km without getting altitude sickness. Perhaps this is different for Rac'cona?

[Jaydub]

Ah, but remember that this is not earth. We do not know at what height you need oxygen.

[Tom Mazanec]

Good point. But we know humans are roughly human size. That means gravity is roughly 1G. That means falloff of air pressure is about the same as on Earth. Maybe oxygen has a lower concentration on Airith's surface? That might affect the Racconnans on Earth in my thread on Racconnia popping up here. Higher oxygen concentrations than you are used to can have...interesting mental effects.

[Chaser617]

Well, actually, you don't 'need' O2 till 10k feet on 'our' world. Thats when things start to pressurize and when military air crews for combat aircraft put on their O-masks even if their aircraft is pressurized (which most are).

[PeterSwinkels]

Ah, but remember that this is not earth. We do not know at what height you need oxygen

Oh, I forgot, the comic has given several hints that doesn't take place on earth, but, those figures still seem wrong to me. 1km is a pretty low altitude. But, I did consider that the altitudes above which air sickness (or whatever) can occur could be different from humans for Rac'cona. To quote myself:

Perhaps this is different for Rac'cona?

Higher oxygen concentrations than you are used to can have...interesting mental effects.

I don't know much about this, but, I read somewhere that breathing more oxygen than you're used to temporarily can improve your memory and I also read that really low oxygen levels can cause interesting mental effects as well.

[RHJunior]

It was an overestimation on my part. I'd been informed that 6,000 feet was the height you'd start needing oxygen, or at least a pressurized cabin....

[Atarlost]

Smaller animals tend to have faster metabolisms. That may or may not effect the pressure required for normal breathing. If it does then racconans would need to start pressurising their craft at lower altitudes.

[Dragoncry]

Salt Lake City, in Utah, is about ~4000 feet, or area's near it at least are. The mountains you can climb nearby will take you up to 5500 feet. Worst I got there was a nosebleed. (stupid me going from ocean level to mountain climbing.

At 10k feet you'll could use some help, but it's not required if you allow yourself to become acustom to it. Many of your normal mountain climbing mountains are about that level.

But. This isn't earth, and they're not human, so it's a moot point.

(the cabin can be sealed? to hold the O2 in?)

[Catherine_Puce]

She probably can hold well the oxygen, there will be lost. But remember that the luxpump create hydrogen from water, my guess is that this thing most discharge pure oxygen. You can probably set the luxpump to discharge the hydrogenthat you don't need and produce oxygen for the cabin. This will be pure oxygen so even if you lost of good part from a not so airtight cabin, you will still have enough of oxygen to breathe.

It's more the frost that rule in high altitude that most determine the maximum safe high. You see you lost 2-3 degree celcius by 300 meters. This seem few but when you reach 6000 feet it's roughtly 12-18 degree celcius of less. I learned from all the year when lived in the north section of the Canada that mechanical engine have this tendancy to not work well outside of a good temperature treeshold. Nobody want see their propulsion system stop to work and get send by the wind. Beside if the water froze in the tank of the luxpump, this risk to break. It's preferable to stay in low alitude even if this attract the attention of the human.

Je me demande s'ils vont prendre ce dirigable pour un monstre.

S.P.P.

[The JAM]

[...unWARP!!!]

Good evening.


Mexico City is some 2 km above sea level, and the bullfighting association does not allow bulls weighing more than 400 kg in the Plaza México. They tend to suffocate.

Tibet now has the highest railroad in the world, surpassing a Peruvian line, at 4 km above sea level, 200 m higher than the one in Peru. Both need oxigen services like you have in airplanes.


¡Zacatepóngolas!

Until next time, remember:

I

AM

THE

J.A.M. (a.k.a. Numbuh i: "Just because I'm imaginary doesn't mean I don't exist")

Good evening.

[WARP!!!]

[MikeVanPelt]

Salt Lake City, in Utah, is about ~4000 feet, or area's near it at least are. The mountains you can climb nearby will take you up to 5500 feet. Worst I got there was a nosebleed. (stupid me going from ocean level to mountain climbing.

At 10k feet you'll could use some help, but it's not required if you allow yourself to become acustom to it. Many of your normal mountain climbing mountains are about that level.

There's a steady stream of tourists to the top of Pike's Peak, a bit over 14,000 feet, with no extra oxygen. Granted, it's short-term visits for the tourists, but the gift shop and snack bar people are up there all day.

I went skiiing once at Arapahoe Basin, and it's above 10,000 feet. I sure did notice the effects of altitude, though. Not as bad as Pike's Peak, where I felt distinctly woozy. (I'm from sea level, not Colorado, so I wasn't acclimatized to even so much as Denver's altitude.)

I'm sure there's some level of impairment above 10,000 feet, which is why pilots are required to be on oxygen. (I think I recall something like 10,000 feet being the equivalent of a couple of shots of whisky.)

But. This isn't earth, and they're not human, so it's a moot point.

(the cabin can be sealed? to hold the O2 in?)

The thing that really interestes me a lot is, they know about oxygen.

Think about that.

They know about oxygen. They have know about oxygen for some time. Humans didn't know about oxygen until the 1770s. (Which fits my impression of Rac Conan society as being much more Renaissance/Enlightenment/dawn of industrial revolution type civilization than medieval.)

[Kerry Skydancer]

My own personal ceiling is about 9000 feet before altitude sickness sets in. (I get it bad. OTOH, I seem to be nearly immune to motion sickness.) But as JAM noted about the bulls in reverse, smaller animals are -less- prone to oxygen starvation, so the Racconans shouldn't have much trouble below 3,000 meters = 10,000 feet.

[EdBecerra]

Of course, it helps to live at altitude. I'm at 4000 feet, so I barely notice 8 to 10 thousand.

Of course, perhaps RH meant 3000 to 6000 feet above the ground. Which means if the ground's at 4000 feet above sea level (as it is here where I live), the luftship could cruise 3000 feet above that.

[Chaser617]

Really depends on the stresses being put on the body at the moment. Like I said, combat flight crews don their O-masks at 10k feet under 'routine' flying conditions in case of depressurization. Now, when entering into combat, they are donned automatically no matter the altitude, because the stresses air combat, both air to air and mud-moving are rather extream and the body uses up a suprising ammount of oxygen in them, and they found pilots started having problems at altitudes as low as 2k feet without an influx of O2. Suprisingly enough, while a carrier landing is more stressful, it dosen't use up quite so much O2, but from what I have been told, and reaserch, its become common practice for navy crews to wear their masks when doing a night appraoch now.

[RHJunior]

Sigh.

And I repeat:

The altitude estimation was off the cuff, based on hearsay.

I felt it was rather low, but went with it anyway.

It's been a few centuries since anyone really took one of those babies as high as it could go--- I think Quentyn and his advisers can be forgiven for getting their estimates wrong.

More than likely the balloon can hit at least twice that altitude, but without anyone having taken it higher than 3,000 feet in all those centuries, erroneous assumptions would accumulate.

Also, you have several different <a href="http://forums.comicgenesis.com/posting. ... ">altitude measurements</A> to consider---
* True altitude is the elevation above mean sea level. In UK aviation radiotelephony usage, the vertical distance of a level, a point or an object considered as a point, measured from mean sea level; below the Transition Level this is referred to over the radio as altitude.

* Absolute altitude or height is the elevation above a ground reference point, commonly the terrain elevation. In UK aviation radiotelephony usage, the vertical distance of a level, a point or an object considered as a point, measured from a specified datum; below the Transition Level this is referred to over the radio as height, where the specified datum is the airfield elevation.

* Indicated altitude is the reading on the altimeter when it is calibrated to the local barometric pressure, referred to as the "altimeter setting".

* Pressure altitude is the elevation above a standard datum plane (typically, 1013.2 millibars). Above a transition altitude, which varies by nation, pressure altitude is used to set the altimeter. Pressure altitude divided by 100 is referred to as the flight level.

* Density altitude is the altitude in the International Standard Atmosphere (ISA) at which the air density is equal to local conditions. Aircraft performance depends on density altitude, which is affected by barometric pressure and temperature. On a very hot day, density altitude at an airport may be so high as to preclude takeoff, particularly for helicopters or a heavily loaded aircraft.


Quentyn or the others might have easily gotten those terms confused. (I know I am! )

[JakeWasHere]

Sigh.

And I repeat:

The altitude estimation was off the cuff, based on hearsay.

I felt it was rather low, but went with it anyway.

It's been a few centuries since anyone really took one of those babies as high as it could go--- I think Quentyn and his advisers can be forgiven for getting their estimates wrong.

More than likely the balloon can hit at least twice that altitude, but without anyone having taken it higher than 3,000 feet in all those centuries, erroneous assumptions would accumulate.

Not to start writing for you, Ralph, but you might actually make the erroneous measurements a plot point. Suppose Quentyn makes a misjudgment and pulls up to 8000-8500 ft. without turning his O2 tank on. When he realizes what he did and that he's not getting very light-headed... no doubt it's a discovery worth noting in his journal. "July 27: Currently cruising at 8500 ft. above sea level. Atmosphere not as rarefied as expected."

[Dragoncry]

Awe... don't worry too much about it. it's not that we're trying to really nitpick, it's just fun to find little things. Like I said, it's not here, or earth, they're not human's, and it's not tech that we actually know. Besides, a writer is allowed to have creative liberties. That's what makes writing fun.

Anyway, it's a fun point... and an awesome concept.

(and congrats on the kiss!)