Lay the E or what ever size bottle you use horizontally across the seat back braces. The bottle fit very there. Put the regulator on the right side of the plane and you can reach it real well from the drivers chair. Tie it down with straps thru the lightening holes and around the cross brace. It is not in the way of getting junk out of the back baggage area lying there and it keeps the weight further forward than anywhere else in the baggage area.

Hydro Testing O2 cylinders
 

[QUOTEsnipped
Who hydrotests oxy cylinders?
Thanks![/quote]


Noah,
If you live in an area where suba diving is popular, the shops who test suba tanks can do it.
Charlie Kuss

So this may be a dumb question:

I assume that the medical tanks are built to such a spec that the relatively lower pressure at (say) 20,000 has no appreciable effect on the integrity of the tank?

I too want to build O2 jacks into the plane so that I can just "plug it in". I'm thinking of using the quick-disconnect style jacks for the O2 lines, and mechanical valves just as a "backup" shutoff.

What I'm trying to figure out is: where do I put the tank (in a -9). I've seen the behind the seat photos, but that seems a little exposed to me. Maybe fabricate a housing for the tank(s)? Alternatively, Possibly lay it on the baggage compartment floor and raise the apparent floor?

This would give me more room for computers, etc which could also go in that bay.

Any thoughts are appreciated,

~ Christopher

Hello Christopher-

The lower pressure at 20,000 ft will have no effect on the tank. Sea level pressure is 14.7 psia, at 20,000 ft it is around 7 psia. So if your bottle is at 1800 psig on the ground, it will be at 1807 psig at 20,000 ft. No issue. ;)

Good point. I guess I was thinking more about the ~50% difference than about the absolute magnitude of that difference, now all I need is a cockpit to put it into.

(sigh) Back to the salt mines.

~ Christopher

After reading this and a few other posts, I'm going to try to roll my own oxygen system for my RV-8. Any feedback on things I'm missing?

Here's the gist:
New D size tank from ebay $50
High purity tygon tubing $1.58 per foot--$16
Precision Medical regulator--ballpark $20 on ebay

Permanently mounted in the airplane running down the right side of the cockpit ($110 from McMaster.com):
- Quick connect plug mounted in bulkhead facing baggage area--the quick connect socket will be attached with some tubing to the regulator so I can easily remove the tank
- Quick connect sockets with shutoff valves installed in the front and back with matching plugs on the cannulas

Oximizer cannulas $27 ea from ChiefAircraft.com
with Aerox flowmeters $35 aerox.com.

Ballpark price $300 with (hopefully) a tidy permanent installation of the lines and and easy way put the tank in and out.

Tygon caution....
 

Not sure of the exact tube routing you are contemplating, but be careful if your sytem can leave oxygen in the Tygon tubing with the pressure regulator ON and a mask/cannula disconnected.

I had a similar setup in my sailplane, and discovered a length of Tygon had become an egg after a day in the heat...:eek:... even though the pressure regulator has a low pressure output

You need an ON/OFF arrangement at the tank if your are completely Tygon tube based, or use some copper lines from the regulator to the quick disconnect fitting... not really a big deal.

If you have the regulator mounted on the tank, then that is also the location of the high pressure guage which indicates how full the tank is. This guage should be visible by the pilot.

I am thinking that I may run copper tubing to the QD ports (which I plan to mount by the headset jacks), and then avoid altogether messing about with tubing.

On the other hand, then I need to bend, fit and solder the copper.

Do they make any braid wrapped O2 cables (kind of like some of the toilet tank ones?).

~ Christopher

Yes, there are high pressure hoses - see Post number 37 in this thread from Kahuna for a picture. There are COTS pigtails available online. Try googling "oxygen pigtail" or "Oxygen high pressure hose".

However, I would not run high pressure O2 lines in an airplane, as there is no need. Put a regulator on the tank to take the pressure down and run low pressure tubing - much safer, lighter, and simpler too.

There are a few different low pressure Tygon tubes suitable for air on www.mcmaster.com. In one of the threads above it recommended part #5554K11 which is laboratory clear tubing with a durometer rating of 55A (soft) and a tensile strength of 1650 psi--78 cents a foot. I chose part # 5466K12 which has the same characteristics but a durometer rating of 71a (firm) and a tensile strength of 2,000 psi. I guess I'll see if it has problems--if so, I'm only about $10 for the tubing. There is one more tube, part #5549K31, that has a durometer of 82A and a tensile strength of 6,050 psi for 58 cents--less supple but the bend radius should still be okay. There aren't any reinforced tygon lines suitable for air that are this small.