41,000' HALO Oxygen Jump, Florida

[gowlerk 2,156]

9 minutes ago, billvon said:

There are several reasons that low pressures cannot be dealt with (without pressurization.)  It's not an issue of not having the right procedures/equipment, it's a problem with Boyle's Law.

Yes indeed. But apparently at 41K people can cope using what they are using. There must be a limit line somewhere, but it is a fuzzy one.

[wmw999 2,372]

41 minutes ago, gowlerk said:

But apparently at 41K people can cope using what they are using. There must be a limit line somewhere, but it is a fuzzy one.

Especially being a fuzzy one, it's only some people. Just like altitude chambers hit some people faster than others.

Wendy P.

[billvon 2,881]

On 12/27/2022 at 8:48 AM, gowlerk said:

Yes indeed. But apparently at 41K people can cope using what they are using. There must be a limit line somewhere, but it is a fuzzy one.

Yes.  At 100% oxygen at 41K feet you are getting the same oxygen you get at about 4000 feet on room air.  So if you ordinarily live in Denver it will be normal for you.  For most people they will be getting a little less oxygen than they get at sea level.  Whether the person is OK will depend on their physiology.  Most people will be.

[sundevil777 102]

17 minutes ago, billvon said:

At 100% oxygen at 41K feet you are getting the same oxygen you get at about 4000 feet on room air.  So if you ordinarily live in Denver it will be normal for you.  For most people they will be getting a little less oxygen than they get at sea level.  Whether the person is OK will depend on their physiology.  Most people will be.

This would imply we can go much higher than 41k.  

[sfzombie13 322]

well, they've jumped from 138k, or so, right?

[billvon 2,881]

9 minutes ago, sundevil777 said:

This would imply we can go much higher than 41k.  

Not much higher, but a little higher.  If you had acclimated to, say, 10K feet over the course of a few months (say in Alma, Colorado) you could probably go to 46K and be OK 9 out of 10 times.  You'd have to prebreathe oxygen for a significant time and then ascend slowly enough that decompression illness was not an issue.  You might even get a few more thousand feet if you went to an overpressure system, where the mask pressure was kept a PSI or so higher than ambient.  However, doing that for any length of time is very fatiguing, and would probably cause more problems than it avoids.  (I experienced this on an early 30K system.  It was not pleasant - and it only lasted 5 seconds or so.)

Of course, going off O2 for a few seconds at those altitudes would lead quickly to unconsciousness and death, so you'd want a very redundant system.

Above 60K or so the boiling point of water gets below body temperature, so that's the hard limit there.

[pchapman 278]

49 minutes ago, billvon said:

Yes.  At 100% oxygen at 41K feet you are getting the same oxygen you get at about 4000 feet on room air.  So if you ordinarily live in Denver it will be normal for you.  For most people they will be getting a little less oxygen than they get at sea level.  Whether the person is OK will depend on their physiology.  Most people will be.

Yeah there's something wrong with the math there. Double check your sources.

I don't have good sources at hand but have seen it written on aviation sites that 40,000 ft on 100% oxygen is like 10,000'.  And the alveolar partial pressure of oxygen (what counts, after removing the partial pressure of water vapour), at 42,000ft looks like it is the same as at 14,000', according to a big 2008 aviation medicine text (although using data from an earlier study).

That's why something around 41,000' is the typical limit without pressure breathing, as that gets you to around the equivalent to the height where you normally want to start looking at going on oxygen if flying for a longer period.

(....assuming the best case where your oxygen system is working perfectly and you have a good mask seal.)

As you say, partial pressure breathing (your term was overpressure) can get you a little bit more oxygen, a bit higher.

 

[gowlerk 2,156]

49 minutes ago, sundevil777 said:

This would imply we can go much higher than 41k.  

Except that as Mike has pointed out several times there are no aircraft available that can go there. All known civilian jumps higher than 41K have been from a balloon and used a full pressure suit. Could the body stand to go higher? It is a moot point.

[michaelmullins 81]

On 12/28/2022 at 5:00 PM, pchapman said:

Yeah there's something wrong with the math there. Double check your sources.

I don't have good sources at hand but have seen it written on aviation sites that 40,000 ft on 100% oxygen is like 10,000'.  And the alveolar partial pressure of oxygen (what counts, after removing the partial pressure of water vapour), at 42,000ft looks like it is the same as at 14,000', according to a big 2008 aviation medicine text (although using data from an earlier study).

That's why something around 41,000' is the typical limit without pressure breathing, as that gets you to around the equivalent to the height where you normally want to start looking at going on oxygen if flying for a longer period.

(....assuming the best case where your oxygen system is working perfectly and you have a good mask seal.)

As you say, partial pressure breathing (your term was overpressure) can get you a little bit more oxygen, a bit higher.

 

We have recorded data on oxygen saturation on actual jumps from 41,000' and 15,000', both in the aircraft and in freefall.  The jumpers from 41K have a higher oxygen saturation with their supplemental oxygen than the jumpers from 15K without supplemental oxygen.  To my knowledge, we are the only ones to record such data.  Actual data and experience trumps theory and speculation.  We will continue to record such data.  Our systems, both onboard and freefall, provide much more oxygen than is required by the generally accepted formula of 1 LPM per 10,000', and we check all the systems with a flowmeter prior to each jump.

Mike Mullins

West Tennessee Skydiving

[cdcollura 5]

On 12/25/2022 at 9:36 AM, alygator said:

Also record for the more expensive commercial jump?

 

Probably in a sense.

The chart says $11k per jumper to 41k with 6 jumpers. I think there were 4, so $15,000 per jumper. Either a brand new jet ski (or small car), or 3 mins of free fall. I think most of the cost is towards the required FAA paperwork and not just equipment / Aircraft. Remember you are also jumping from RVSQ "special qualifications" airspace (above 28.5k MSL which was imposed in 2002 after 9/11) ... Things like this simply ARE NOT CHEAP now. Especially in this day and age.

[michaelmullins 81]

5 hours ago, cdcollura said:

Probably in a sense.

The chart says $11k per jumper to 41k with 6 jumpers. I think there were 4, so $15,000 per jumper. Either a brand new jet ski (or small car), or 3 mins of free fall. I think most of the cost is towards the required FAA paperwork and not just equipment / Aircraft. Remember you are also jumping from RVSQ "special qualifications" airspace (above 28.5k MSL which was imposed in 2002 after 9/11) ... Things like this simply ARE NOT CHEAP now. Especially in this day and age.

Actually there is no cost for FAA paperwork to do the actual jumps.  The procedure for a specific jump approval is just tedious and time consuming but, other than the time invested, there is no cost.  There was a large, one-time, cost for the approval for flight with door removed, flight testing, and the interior configuration. 

The term for the airspace involved is actually RVSM, which is Reduced Vertical Separation Minimums, which requires very special digital altimeters, special auto-pilot, and other equipment for flights above 28,000'. 

As the aircraft is used for nothing but these jumps, and would not be practical for normal jump operations, the cost of operation must be absorbed by a limited number of customers who can afford such jumps. 

There are many things that are not available to the average person, or skydiver, due to cost and that is why everyone does not own a Ferrari, go to the ISS, and live in mansions.  But, there are some that can and do.  A private citizen went to the ISS, cost him 28.5 million.  An 18 year old went up in Bezos rocket for the 15 minute flight, cost 2.8 million.  Virgin Galactic ride to the edge of space sold out 800 slots for $250,000 each, now the ride costs $450,000.  Very special things take very special money.

Michael Mullins

[JoeWeber 2,670]

4 hours ago, michaelmullins said:

Actually there is no cost for FAA paperwork to do the actual jumps.  The procedure for a specific jump approval is just tedious and time consuming but, other than the time invested, there is no cost.  There was a large, one-time, cost for the approval for flight with door removed, flight testing, and the interior configuration. 

The term for the airspace involved is actually RVSM, which is Reduced Vertical Separation Minimums, which requires very special digital altimeters, special auto-pilot, and other equipment for flights above 28,000'. 

As the aircraft is used for nothing but these jumps, and would not be practical for normal jump operations, the cost of operation must be absorbed by a limited number of customers who can afford such jumps. 

There are many things that are not available to the average person, or skydiver, due to cost and that is why everyone does not own a Ferrari, go to the ISS, and live in mansions.  But, there are some that can and do.  A private citizen went to the ISS, cost him 28.5 million.  An 18 year old went up in Bezos rocket for the 15 minute flight, cost 2.8 million.  Virgin Galactic ride to the edge of space sold out 800 slots for $250,000 each, now the ride costs $450,000.  Very special things take very special money.

Michael Mullins

Yep, that's just how the world rolls. Two Buck Chuck is available to every wine drinker but if you desire something different, and special, the price goes up disproportionally. Folks only complain about wine snobs until they share the stash, funny that.

[billvon 2,881]

On 12/29/2022 at 4:00 PM, michaelmullins said:

Our systems, both onboard and freefall, provide much more oxygen than is required by the generally accepted formula of 1 LPM per 10,000'

I hope that means you are using a demand or diluter/demand system that does not set flow rates.   

[michaelmullins 81]

4 hours ago, billvon said:

I hope that means you are using a demand or diluter/demand system that does not set flow rates.   

As I have said on numerous occasions we use a diluter/demand/pressure regulator, A-14, which is good to at least 45,000'.  We never set them on diluter, they are always on 100%, and they have pressure breathing settings for 41K, 43K, 45K, and above 45K.  They will automatically start pressure breathing if you do not select the pressure breathing.  At around 30K, we put them on 45K and they put out a lot of oxygen, in excess of 12 LPM, which is far more than you can use.  The system does not technically set flow rates, the flow rates are the result of how much pressure is coming out the diameter of the hose.  The pressure is way more than sufficient, it is uncomfortable until you get used to it, it is akin to being waterboarded with oxygen.