The Random thought thread

[nomadpete]

22 hours ago, Jerry_Atrick said:

I second that and extend it to humanity.

All the world, excepting thee and me....

[old man emu]

If an undersea diver surfaces too quickly, they can get "Decompression sickness", also called generalized barotrauma or the bends, injuries caused by a rapid decrease in the pressure that surrounds you, of either air or water. We never think that it also can occur during high-altitude or unpressurized air travel, as happens when someone leaves the back door open on an airliner.

[facthunter]

IF you have been diving (SCUBA) and fly soon after you CAN have issues with nitrogen bubbles forming in your blood as you go to higher cabin altitudes. I once  was  asked IF I  would/could  return to Christmas Is and bring the plane  to Perth with the cabin at sea level for a person with the Bends. who was in a bad way (plane at FL 170 max to keep the cabin on the ground and the patient had to be in a BARO chamber for a number of days in Perth to recover..  There's NO 3 engine cruise chart for FL 170. in the B 727 flight manual.   Nev

[spacesailor]

AND, I thought you were talking about the " drifter " .

( at sea level flighting.)

N E S  thread .

spacesailor

[facthunter]

Just responding to OME's  post. I mentioned CABIN 3 times. What is NES thread?  Nev

[willedoo]

I don't know much about diving, but it obviously has reverse issues to high altitude flight in an unpressurised cockpit. The deeper you dive, the higher the external pressure on the lungs requiring an adequate overpressure supplied to the lungs. I read somewhere that with the high pressure the haemoglobin can get bombarded with too many oxygen cells and reacts by tossing them off causing oxygen deprivation. I don't know for sure whether that's true or not.

 

HA unpressurised flight is quite different. From 40,000' up an overpressure in the lungs is needed otherwise the partial pressure of the oxygen isn't enough to make the O2 molecules stick to the haemoglobin. You can have 100% O2 and it doesn't do any good unless it can bond to the haemoglobin. In unpressurised HA flight, breathing in the overpressure is easy but lack of ambient external pressure on the lungs makes it difficult to exhale, hence the use of a pressure jerkin or a partial pressure spiderman suit to create an artificial external pressure on the chest. The opposite of diving where there can be too much external pressure.

 

I read an interesting (for me anyway) article written by a retired Russian test pilot who flew to something like 58,000' in an unpressurised cockpit with an open face helmet. He described the physical difficulties he encountered with the low ambient pressure. I'll see if I can find it again.

[willedoo]

Pressure breathing in an unpressurised altitude environment seems to me to be opposite to natural breathing. With natural breathing we put a conscious effort into breathing in, but to breathe out our diaphragm relaxes and the ambient external pressure automatically pushes the air out of the lungs. With pressure breathing, the first part of inhaling opens the pressure demand valve in the regulator and then the O2 supply does most of the work filling the lungs. With the lower external pressure and even with a pressure vest or partial pressure suit, the pilot has to make a conscious effort to breathe out, the opposite of normal breathing. In various youtube videos, via the mask microphone, you can hear the heavy breathing of the pilot on exhaling but not so much when inhaling.

[facthunter]

The bubbles in the blood are like what happens when you take the top off a bottle of lemonade. The pressure decreases and them gas comes out of solution. The gas in the bends is Nitrogen bubbles I believe,  and a product of extra pressure at depth and time spent there. Going flying after diving will exacerbate the condition. That's why the MSL pressure was needed to be maintained.  to reduce the risk.  Anyone flying after diving deeper than  a certain depth faces SOME risk. but this person needed to get to a baro chamber relatively quickly.   Nev

[willedoo]

I found that article by the Russian test pilot. He described the ascent to 18,000 metres (59,000 feet) in an unpressurised cockpit with an open face helmet and mask. As it's close to the Armstrong line, that's about as far as you can go without a hermetic helmet and not cause significant injury or death.

 

He wrote of two scenarios of depressurisation at 59,000 feet; a sudden explosive depressurisation, and a slow smooth ascent as would be experienced in a leaky cockpit. With an explosive depressurisation, the ambient pressure at 59,000' is about 1 psi and the life support system activates immediately. If a flight suit is worn over the  altitude-compensating suit, it will rapidly expand as if by a small explosion inside, then collapse against the body. The way I see it, that would be due to the air between the two suits expanding because of it's pressure being much higher than ambient, then escaping from the suit to flatten it. At the same time the altitude-compensating suit squeezes the body tightly like a blood pressure device cuff. Air comes out from everywhere: from the ears, eye sockets, nasal cavity and of course farting.

 

He wrote that the slow ascent was much more uncomfortable as the symptoms happen gradually rather than in one big shock like scenario #1. The altitude-compensating suit squeezes more and more as the altitude increases. Using a regular oxygen mask, air begins to leak out of the ears, eye sockets, nose and esophagus, but not instantly as with explosive decompression, but increasingly.

 

His symptoms of hypoxia started at 52,000'; a strong burning sensation, goosebumps, cold sweat, ringing in the ears, and peripheral vision narrowing. Nausea and severe abdominal pain appeared . At 59,000', vision narrowed to a small spot in the center, severe ringing in the ears, burning throughout the body and cold sweat, the altitude-compensating suit squeezed the body painfully, and oxygen entering in excess pressure not only made breathing difficult, but also seepage caused excessive tears in the eyes making it difficult to see with small tunnel vision. Another effect was a strong smell sensation of ozone.

 

Those were his physical symptoms. Apart from that just the expected light headed euphoria, false sense of security and going a bit loopy before doing a fairly rapid descent.

 

 

Edited January 9 by willedoo

[pmccarthy]

When I was young I worked in a mine 3500 feet deep and before work I did flying lessons at around 5000 feet a couple of days a week. Had no effect, except for the farting. That has persisted, like long Covid.

[Marty_d]

2 hours ago, pmccarthy said:

When I was young I worked in a mine 3500 feet deep and before work I did flying lessons at around 5000 feet a couple of days a week. Had no effect, except for the farting. That has persisted, like long Covid.

Wow, I must have contracted it a different way, never been that far below ground...

[nomadpete]

15 hours ago, willedoo said:

Pressure breathing in an unpressurised altitude environment seems to me to be opposite to natural breathing.

A related random anecdote, which I relate as well as I can recall:-

 

I once met the gentleman who briefly held the Australian height gain record with GFA.

 

He flew a Blanik in central Australia and he had learnt gliding in Europe where flying in cloud was permitted. On the day in question he had taken a barograph on the flight, hoping for a cross country trip but the sky overdeveloped and he was returning to land when a lovely nearby cumulonimbus got his attention. He went under, and shot up into the moist grey. Dressed only in shorts and tee shirt he got very cold. After riding the intense buffeting for a time He watched the altimeter winding up and up. After it went past 30,000' he fogging realised that there wasn't much point in going higher  because the clockwork barograph only went up to 30,000. So, shivvering and freezing, he straightened the Blanik up, put the nose down and popped out into clear air.

 

Later, the barograph showed 40kts of lift in places, and 40kts of fall at times! He didn't  say how long the flight lasted but it must have been a wild ride!

 

To this day I am fascinated by the human side of it. How did he function without oxygen?

[pmccarthy]

I am surprised that pilots on both sides in WW1 got to 20,000 feet for periods of 10-15 minutes without oxygen. They usually got quite ill at the end of it and some blacked out, to recover in a spin at lower altitudes. By mid 1918 they were using oxygen and patrolling up to 21,000 feet. At the extreme altitudes, a height advantage of 50 feet would determine whether you could bring your guns to bear on the enemy, or stall and spin as you raised the nose.

[facthunter]

If you are FIT and partly conditioned you could handle those levels. Trouble is hypoxia is subtle and you get a feeling of euphoria and wellbeing. Your nails go dark and you can't sign your name or add up. Blacking out is with high"G" where the blood drains from your brain.   Nev

[willedoo]

12 hours ago, nomadpete said:

After it went past 30,000' he fogging realised that there wasn't much point in going higher  because the clockwork barograph only went up to 30,000. So, shivvering and freezing, he straightened the Blanik up, put the nose down and popped out into clear air.

At 30,000', the outside temperature is -44C. I've been in -40 and that was enough for me. Lucky I didn't get frostbite.

[willedoo]

A blackout would be preferable to a negative G redout in a lot of ways. At least with a blackout you have a chance of coming to and regaining control. With a redout you can have retinal damage and even a brain bleed causing impairment.

[pmccarthy]

I have been on minus 40 a few times, in the Arctic. My main memory is wanting to be somewhere else.

[willedoo]

1 minute ago, pmccarthy said:

I have been on minus 40 a few times, in the Arctic. My main memory is wanting to be somewhere else.

I came across -40 in northern Alberta. -30 and even -35 was tolerable, but -40 was another level like being in a big meatworks freezer. My problem was I didn't have the right boots for it and the cold was getting through the soles. Ten minutes of walking took twenty minutes to thaw the feet out. I didn't know feet could hurt like that.

[spacesailor]

Kids,  in Northern England often got ' frostbite on their toes .

In the fifties before ' global warming. ' 

And had to apply " SNOWFIRE CREAM " To the darkened toes .

CHILBLANES we called it .

spacesailor 

[onetrack]

I can recall a mate telling me how he went to Chicago in the dead of Winter and walked outside his hotel - and it was -14 deg (F).

He related how you had to be careful taking too-deep breaths, or icicles would form in your lungs, and do serious damage to them.

 

I've seen a video of a person in Northern Canada, up near the Arctic Circle, walking outside their hut, at a temperature of around -35 deg, with a washbasin full of warm water (that they'd just washed their face in) - and they threw the water into the air - and it came down and hit the ground as chunks of ice, like iceblocks.

[Jerry_Atrick]

My first gig when moving to the UK was actually in Bismarck, North Daktoa, in the winter of 96/97/ It got down to -30-odd degrees.. I can tell you, it is flippin cold.

 

When I arrivedat the hotel (really a motel) with the rental car, I noticed that there were electricity points sticking out from poles muc liek you would get at a caravan park. When I asked reception why they have a RV Park (proud of being able to speak American). They asked what I was talking about. "You know - in the car park - all those power points you have..."

 

"Or sir, they aren't from caravans. You should have a power jack on hanging off your front grill. That is to use your dipstick as a heater to stop the oil freezing."

 

*gulp*. I went outside, found the jack and plugged it in.

 

I bought, back then, somne North Face gloves for over $100, and my hands were still cold.

[spacesailor]

Only One thing to Say .

Long Live Global Warming .

Happy at 30 + c.

spacesailor

[red750]

Here's a random thought. Is not undergoing a sex change to match your mental identity a bit like changing your foot to fit the shoe?

[facthunter]

Maybe you'd better write that again.??  Nev

[pmccarthy]

3 hours ago, red750 said:

Here's a random thought. Is not undergoing a sex change to match your mental identity a bit like changing your foot to fit the shoe?

If you had a foot you probably would just get it cut down to six inches.