# Experimental Aircraft Oxygen Systems

### Help Support Homebuilt Aircraft & Kit Plane Forum:

#### Riggerrob

##### Well-Known Member
I suspect that the continued myth about aviators' breathing oxygen relates back to World War 2. Back then the air Force was an early adopter and had enough money that they could write a new standard. After a while, chemical plants grew weary of operating 2 or 3 different quality control standards, so narrowed their offerings to medical oxygen. Aviator's oxygen has to be dry to avoid freezing valves at higher and colder altitudes.
Meanwhile, welders consider water - or any other contaminate - a nuisance.
Finally, medical oxygen arrives "dry" and is piped through a humidifier before hosed to the patient's mask.
Since it is a quality control and logistics hassle - to maintain 3 different standards in the same factory - oxygen suppliers simply work to the purest standard. If customers complain about paying too much for more quality than they need, they are referred to the next supplier. The next supplier is a few hundred miles (kilometers) away and transporting oxygen requires "Hazardous Goods" certification to tranport.

Note: as an enlisted maintainer (Royal Canadian Air Force) I heard plenty of antiquated myths repeated. ... and people wonder why I am skeptical of officials repeating dogma. Hah! Hah!

#### Bigshu

##### Well-Known Member
I did some serious investigation into this possibility. The problem is that the regulators available
are by no means in good shape. He was lucky to get one that the seller showed was working.
And that he could test and see if it was working.

If you get one like the Scott Regulator he used and you want to get it overhauled it's $2000. You can buy a new A-12A diluter-demand regulator good up to 32,000 feet for$1900. This one looks like the ones used in 1940's-1950's airplanes.

So yeah you can do that route but it turns out to be very expensive. I looked into this because I wanted to do what Paul Dye did. But it's very pricey.

Or you buy an old regulator and hope that it works, or, if it does, that it continue working. I didn't choose to risk my life that way.,
Yeah, I looked at surplus regulators and came to a similar conclusion. I did find a cheap regulator/diluter from an F-86 that I bought, just because it's cool...I think the other solutions kicked around on this thread sound more practical and cheaper. I prefer a mask to a cannula too, and I wonder how to get good comms with a pharmacy oxy mask. I guess my old helmet/mask setup can go in a display case!

#### Saville

##### Well-Known Member
Yeah, I looked at surplus regulators and came to a similar conclusion. I did find a cheap regulator/diluter from an F-86 that I bought, just because it's cool...I think the other solutions kicked around on this thread sound more practical and cheaper. I prefer a mask to a cannula too, and I wonder how to get good comms with a pharmacy oxy mask. I guess my old helmet/mask setup can go in a display case!

I really dislike cannulas and I'd like to use my MS-22001 mask. I bought a new mike that fits into it and the amplifier that takes you from military to civilian and tested it out - it works great. See attached photo taken during the flight test.

So there are two other options:

CRU-79/P Oxygen Regulator
- As Paul Dye says:

"It is designed as a pressure-demand system, supplying 100% O2 at a pressure to the mask slightly above ambient at all times. This is good for feeding oxygen to the pilot, but not so good at conserving O2"

So we'd need a bigger tank for our 1-2-3 hour flights.

Or - run the hose from a cannula system up the larger hose of the mask, and fasten the cannulla inside the mask so that it's near your nose. The second picture here is the inside of my mask. There is a rubber bridge that runs underneath your nose. One could imagine the cannulla just above that rubber bridge. Fastened on with some silicone.

You get all the benefits of a system that is less expensive and makes the O2 last longer. What I don't know is whether or not the O2 vs CO2 levels inside the mask are better, worse or the same as compared with the canulla only.

#### Attachments

• 42.1 KB Views: 11
• 55.4 KB Views: 10

#### Rhino

##### Well-Known Member
The Paul Dye article is here:
Unfortunately it mainly involves converting military masks, which isn't the topic of this thread, and there is no sidebar on medical oxygen online. The print issue could have that sidebar though. I haven't checked my back issues.

Something that applies more directly to the topic here is:

As for the type of oxygen used, this could be of interest:

Not recommending it as a solution for anyone else, but I'd personally go with the O2D2 system from Mountain High with an appropriately sized kevlar (more expensive but light) bottle. Then I'd consider tossing in a bubble humidifier for an extra $1.74, because breathing dry oxygen for long periods isn't healthy. That probably won't be necessary for my lower altitudes though. #### Bigshu ##### Well-Known Member Or - run the hose from a cannula system up the larger hose of the mask, and fasten the cannulla inside the mask so that it's near your nose. The second picture here is the inside of my mask. There is a rubber bridge that runs underneath your nose. One could imagine the cannulla just above that rubber bridge. Fastened on with some silicone. I was wondering if anyone had done this. It seems like the best of both worlds: purpose built mask with comms and modern air line system. My mask uses the J style bayonets, and I hate to give up on the fit and function. It's not like I need oxygen for the flight levels, I just feel sharper and less fatigued with oxygen around 8 or 9 thousand. #### Rhino ##### Well-Known Member Lifetime Supporter Considered adapting my old Air Force helmet at one time, but there's not much call for it in a Zenith STOL. Got the CRU-60P around here somewhere too. #### Saville ##### Well-Known Member The Paul Dye article is here: Unfortunately it mainly involves converting military masks, which isn't the topic of this thread, and there is no sidebar on medical oxygen online. [/URL] This article includes how to make your own refilling station. Mainly - but not totaly. He uses a blue covilian mask The Paul Dye article is here: Unfortunately it mainly involves converting military masks, which isn't the topic of this thread, and there is no sidebar on medical oxygen online. The print issue could have that sidebar though. I haven't checked my back issues. Something that applies more directly to the topic here is: As for the type of oxygen used, this could be of interest: This article includes how to make your own refilling station. Not recommending it as a solution for anyone else, but I'd personally go with the O2D2 system from Mountain High with an appropriately sized kevlar (more expensive but light) bottle. Then I'd consider tossing in a bubble humidifier for an extra$1.74, because breathing dry oxygen for long periods isn't healthy. That probably won't be necessary for my lower altitudes though.

Actually the Paul Dye article wasn't about converting a military mask but using one. To me a mask is a mask and is pertinent to the topic title:

Experimental Aircraft Oxygen Systems

Mill masks and diluter-demand systems are one option that just as directly relates to the thread title as any other, though an expensive one.

Thanks for the link to the Homebuilt O2 Kitplanes article. Looks interesting.

#### Martin W

##### Well-Known Member
.

Just a sidenote about welding oxygen not being recommended as medical oxygen .

They don't want people going down to the dirty and grimy blacksmith shop to get their breathing oxygen .

It is mostly a precautionary statement .... just like the diet and exercise people who tell you to see your doctor before going for an evening walk. Nobody actually calls the doctor .

Medical and aviation professionals can never endorse anything "outside the box" because they have responsibility and liability issues . The oxygen itself is just fine.

.

#### Rhino

##### Well-Known Member
...Actually the Paul Dye article wasn't about converting a military mask but using one. To me a mask is a mask and is pertinent to the topic title:...
Maybe conversion would have been a better word. I was just trying to keep within the context of the original post. The sub FL180 environment he described didn't really seem to be a military mask type scenario. It doesn't completely preclude them though, so your point is well taken.

#### WWhunter

##### Active Member
Strange, the welding shop in my area is the same place that medical oxygen bottles are filled. The may have a seperate system for filling them, but they are done at the same location.

#### Bill-Higdon

##### Well-Known Member
Strange, the welding shop in my area is the same place that medical oxygen bottles are filled. The may have a seperate system for filling them, but they are done at the same location.
All of the O2 comes from the same dewars, no marking difference in the ones I've seen in the past 20+ years

##### Member
Interesting update. Heard in A&P school that medical and aviation "oxygen" are different because of the water in the medical. Had not heard about bubbling oxy for the patients.
The A&P school I went to said there was no water in the oxygen. Water in an oxygen tank would be highly corrosive.

#### rv7charlie

##### Well-Known Member
The A&P school I went to said there was no water in the oxygen. Water in an oxygen tank would be highly corrosive.
Same would be true for any O2 source; that's why med O2 uses external humidifiers between the supply & patient; not in the O2 supply.

#### wktaylor

##### Well-Known Member
Be careful with the essence of life...

Pilot's guide to portable oxygen systems... Pilot's guide to portable oxygen systems

Staying Alive: What Oxygen System You Need When Flying Above 12500... Staying Alive: What Oxygen System You Need When Flying Above 12,500'

Aircraft Oxygen Systems and Oxygen Filling... Oxygen Systems

AerOX Aerox Aviation Oxygen Systems and Accessories
AviationOxygen Aviation Oxygen, Aerox Aviation Oxygen, Cylinders, Masks, Portable Oxygen - Aviation Oxygen Repair, Overhaul, Maintenance - AviationOxygen.com

#### wktaylor

##### Well-Known Member
Also...

Current generation aviation oxygen tanks/systems are designed to be light weight and high pressure [at the tank]... no more 400-PSI... more like 1500-to-3000-PSI. High volume and light weight = aviation. At these higher pressures there are concerns about leakage and contaminates of any kind... especially reactive oils/lubricants... initiating fire/explosion or human injury... from the tank, thru the valving/regulators, thru the delivery tubing to the crew/Pax face masks. There are special purging/cleaning requirements for the mechanisms, fixed tube/hose systems, etc... to ensure that no contaminants ever enter these assemblies... ever... especially biological and/or chemically reactive materials, to avoid lung injury, sickness or fire/explosion. And yes aviation O2 is so dry-of-moisture, so it is suitable for use at -65F without freezing-up.

In Military Aviation, thru the years, I have been an investigator on ~[4] major mishaps [accidents] involving Oxygen systems... 1-GOX over pressure, 1-LOX over pressure [freezing moisture over the vent], and [2] on-board small-fires that failed the aluminum crew oxygen lines causing a massive O2 fed interior fire. Other mishaps have occurred... mostly leaks, small fires etc that were extinguished fast... without major damage.

NOTE. My mom in her elderly years really needed oxygen... but she was a smoker all her life... and would sneak cigarettes... even when she was coughing at 80-yo+. For this reason, it was determined that her addiction would drive her to smoke... regardless of the rules related to 'medical oxygen'... and that the fire danger was too great to put her on O2. When she was placed in 24-hr care... and sneaky-smoking could have been eliminated altogether... she was too far-gone to benefit from the O2. DANG.

Do NOT take O2 lightly.

OH yeah… for extra credit... why do commercial aircraft emergency 'drop-down' O2 masks include a small 'baggie' between the O2-line and the face mask?

Last edited:

#### Cardmarc

##### Well-Known Member
Aviation Consumer Magazine just had a great article on recent improvements in bottled 02 systems. Worth your time to read!

#### HomeBuilt101

##### Well-Known Member
Wow this thread and the knowledge/ experience shared is amazing...THANKS!!!

#### BoKu

##### Pundit
HBA Supporter
why do commercial aircraft emergency 'drop-down' O2 masks include a small 'baggie' between the O2-line and the face mask?
Because the plumbing into the alveoli has non-trivial volume.