dan2see wrote:I was in the Canadian Air Force in the 1960's, working on the CF104 supersonic jet fighter. That jet was designed to reach 100,000 feet.

Must have been a very interesting career. Canadian aviation design was at its peak in the 50s designing the CF-105. What a sad story for our country. I recently purchased a diecast model of the Arrow, just released from the Canadian Air and Space Museum in Toronto, that sits on my office desk to remind me of what we are capable of doing.

butitsadryheat wrote:http://www.pbs.org/wgbh/nova/everest/exposure/hackett.html

PETER HACKETT: There's evidence that the people who do best at altitude are dehydrated. That is the body resets the serum of molality level which has to do with the water balance. And the body, for some reason, prefers to be dry at high altitude. My own thinking is that this is good for the body because it keeps the brain a little bit drier and softer. So that if it does start to accumulate a little water or get a little swelling, it can be tolerated better.

I wonder if that has anything to do with the fact that I have never experienced any symptoms of altitude sickness aside from loss of appetite. I do know I am usually dehydrated when I am hiking and climbing (I rarely urinate and when I do it is deep orange).

Brad Marshall wrote:

dan2see wrote:I was in the Canadian Air Force in the 1960's, working on the CF104 supersonic jet fighter. That jet was designed to reach 100,000 feet.

Must have been a very interesting career. Canadian aviation design was at its peak in the 50s designing the CF-105. What a sad story for our country. I recently purchased a diecast model of the Arrow, just released from the Canadian Air and Space Museum in Toronto, that sits on my office desk to remind me of what we are capable of doing.

This is OFF TOPIC but the temptation to comment is too much...

The CF-105 Avro Arrow has some kind of sex-appeal, it creates so much comment and thought, 50 years after it was developed, and then destroyed.

[ RANT ]
The Arrow was a high-profile project that proved two things about Canada and Canadians:
1. We can do anything, and have proven so, time after time.
2. Our government, and our corporations, have no respect for our abilities.

The result of neglect and abuse of our technical and scientific abilities leads to these two results:
1. We buy Chinese-manufactured stuff from Walmart.
2. Folks like me can't even get a job.
[END OF RANT]

Back the OP's topic, but I've broadened the OP a little: from "how high could you climb" to "how high could you manage". Frankly, the many skills required just to reach 8000 meters go 'way beyond simple breathing.

Anyone who wants to climb Everest has to raise at least $50,000 for logistic support, not to mention lost wages. That's one aspect of high-altitude that I could not manage: while I'm raising money, I'm not climbing my local mountains.

My own limit is 'way down at 3000 meters (10,000 feet) but the problem is stamina and logistics. I could get a helicopter ride up to its limit, and climb from there. The views would be wonderful but it's not going to happen.

I think the absolute limit is 9000 meters, but that's still only if you are an extra-ordinary individual, well-prepared for the ordeal.

dan2see wrote:I was in the Canadian Air Force in the 1960's, working on the CF104 supersonic jet fighter. That jet was designed to reach 100,000 feet. So the pilot's ejection seat was designed so he would survive the fall, if he ejected from that altitude.

First of all, he'd be breathing an oxygen-air mix already.

For the descent, his seat carried a bottle of O2 that would let him breathe at least down to 20,000 feet -- I think 10 minutes. While falling, his body is idle, so his O2 requirement should be low. Note that his parachute is NOT deployed for the fall. He has only enough oxygen to fall to 20,000 directly (do not stop at go).

The ejection seat assumes that the pilot is unconscious. There had to be a desperate reason why he bailed, and also during the fall, if anything went wrong, he'd no longer have a guarantee of oxygen delivery.

At around 20,000 feet the seat automatically cuts loose, although his survival pack is still tethered below him.

Finally at 10,000 feet (I think) the parachute automatically deploys, and he floats gently to the ground.

Limits to altitude?

I've heard of 16,000 feet marks the "death zone" because the body can no longer rebuild wear-and-tear, and slowly but inexorably begins to die.

The climbers who reach to summit of Everest without oxygen are extra-ordinary folks, and from their stories, you know they've reached the limit.

Those pilots wore pressure suits. Possible for climbers, but VERY restrictive.

Their emergency oxygen was delivered under positive pressure, not a demand system. They would blow through a large amount of oxygen very quickly. Logistically, positive-pressure oxygen systems would be a nightmare at alttiude because of the massive flow rates.

How many bottles of O2 do you need to get one bottle of O2 to high camp? And how many bottles of O2 can you carry on the summit bid?