Oxygen Systems
From a post of mine during Sun-N-Fun 2006
** Just revised 8/15/2006

Well, it looks like the O2 system information for -10's will be as broad as the number of O2 system vendors.  I picked up m portable system at Sun-N-Fun 2006.

At present, I know people who have most every system available for our planes:

I didn't know which way to go, so I read as much as I could about them online.  The mountain high stuff looks very nice, but generally costs a little more.  The mountain high pulse systems conserve O2 very very well, but they cost a LOT of money.  One other vendor (Aerox) told me that MH uses plastic fittings.   No big deal I guess.

The SkyOx system looked good too. At first I thought it might be nice to have a single adjustment knob for all 4 places....then  I read on and rationalized it a bit and realized that each person may not want/need the same amount, so there is a drawback, depending on your needs.  Having a Pulse Oximeter is a real necessity anyway, and having individual controls would be nice.

The Aerox seemed pretty good too.  I almost went with it, and was looking for things to nit-pick to help me decide between Precise Flight and Aerox.  They use the same cannulas, and offered much the same stuff.  The aerox uses needle valves on the regulator.  I thought maybe that depending on what bangs into it, it might not be as durable as an inline meter.  Also,  it means the guy running the system will need to be very close to that valve, whereas if you have a flowmeter inline, you could have the flowmeter close to you but far from the bottle.

In the end, The Aerox was just a few bucks more, if I bought their carry case, and they only included 4 cannulas, meters, and one mask.

My Solution
From Precise Flight, I got 4 cannulas, 4 meters, 4 masks, (1 cannula and mask was kids sized by request), and the carrying case, with an M Bottle.  The aerox was something like $631+59 for the case.   The Precise Flight was $675 for the whole thing.  At OSH 2006, I added a pair of the Demand Conserver units that get attached inline to conserve O2, which cost about $375-450 (ea) depending on special pricing if bought during a show. (I paid $335 ea)    These are supposed to save about 3X to 5X the oxygen as opposed to the oxysaver cannulas.   The demand conservers come with their own "sensing" cannulas with 2 hoses and chambers, one for sensing the inhale, and one for supplying the oxygen.  During my first use they worked very well, but I cannot tell yet if the conservation is actually the 3X-5X quoted to me.  I am finding that Oxygen is a very handy thing to have in a capable cross-country cruising plane like the RV-10.   The Aerox does have a better warranty...the P.F. is 2 years.

I did download and read the Aviation Consumer article on the various O2 systems before buying.  In general, their main complaint about some of the others was the case, mounting, or individual adjustments.  They chose the Precise Flight, and I trusted that it would be a reasonable choice.  I don't really think it's a drastic difference between any of them, so everyone will probably be generally happy with what they have.

Here's a photo of the Demand Conserver



Using the Oxygen
So far I've been very impressed with how much utility flying with Oxygen can bring.  There will be trips that I stay low, to avoid worry about Oxygen, but as a general rule, I plan to use it on most of my longer X/C Trips.  For one thing, I think it's easier for me to run Lean of Peak when at altitudes of about 8500' or greater, so using Oxygen will help guarantee I get into that altitude range.  I've also found it necessary on our Yellowstone trip, to cross the Little Bighorns with plenty of altitude margin to spare.
Installation

I don't have an installed system myself, I use mine portably, so there are better "experts" than myself to look to. Randy did a Mountain High Pulse system, fully installed.  Russ Daves has his system semi-permanent. I'm sure there will be many more.  The only reason I went portable right now is because I didn't know how much I'd use it, and it is easier to ditch the bottle when you're not using it.  The bottle fits nicely between the rear seats, or can be hung in it's bag from a seatback.  Long term, I may just hang it from the rear seats, and semi-permanently install the hoses behind cabin walls.   For those who use it all the time, I'd really recommend looking at Randy's system.

Randy's Mountain High Install
Click the photo to jump to photos of Randy's install

Pulse Oximeters
One thing you don't want to skip is a pulse oximeter.  It's the only way to truly know when you need Oxygen, and how much you are getting.  You should check your level every 15-20 minutes in flight.  They're simple to use...just clip them on your finger and wait a few seconds to read the numbers.  They read your pulse, and Oxygen saturation level.  You'll want that level to be in the 90's as much as possible, and hopefully at 94 or more.  You'll notice many things as you get into the 80's.  I myself start to get a fast heart rate and get generally more paranoid about little things.  You'll also feel more energized after a flight with Oxygen....not that it's energizing you, but it's keeping down your fatigue a bit.   For a great article on these things, check here: http://www.aeromedix.com/aeromedix/art/pulseox/



I have the Nonin Sportstat.  http://www.sportstat.nonin.com/    Also made by the same company, and more commonly found at aviation suppliers is the Nonin Flightstat.  These 2 units are identical, except the sportstat comes with a lanyard attached.  The sportstat targets Hikers and Climbers, whereas the Flightstat targets pilots.  They are also functionally identical to the Nonin 9500, a medical version.  The best one currently out looks like it's the Nonin 9550, which should give better battery life.  I won't go into the specs here.  There are also cheaper models available everywhere, but I don't recommend them.  I've heard that they don't fit small fingers as well, and that they're not as durable.  I got my SportStat on Ebay, which looks to be a good place to buy these things and save a bit of money.  If you price shop, you'll find that Nonin, with a fairly strong monopoly, gets some good cash for these things, and then if you want the Flightstat, you'll even pay more because, as you know, aviation just makes things expensive sometimes.  Here's a comparison to the CheckMate, a cheap one: http://www.aeromedix.com/aeromedix/cat/pulseox/flightstat_comparison.pdf
I just got a .pdf copy of the manual for the FlightStat, which you can download HERE if you want to read it.
Oxygen Filling
First of all, I'd highly recommend reading the article "Getting High on Welders Oxygen" available on AvWeb at http://www.avweb.com/news/columns/182079-1.html

For my background:  I owned a SCUBA store for many years, filling thousands of cylinders over those years.  Sure, SCUBA uses air, but....    I was one of the earlier adopters of Trimix gas mixing in SCUBA diving.  We used Argon in our drysuits for insulation, and we breathed anything from 100% Oxygen for decompression, to mixtures of Helium + Oxygen + Air (O2 + N2) to do extremely deep "Technical" dives.   I spent a great deal of time filling cylinders for all of these gasses as well.  Filling Oxygen isn't 100% risk free, but neither is filling air, or even hauling your Oxygen bottle.  Done safely, there is no issue that you shouldn't be comfortable with.  The biggest thing with Oxygen is using Oxygen compatible materials, and ensuring they're Oxygen clean.  When any gas, including air, is suddenly compressed, it can cause adiabatic compression that will heat the air greatly, and instantly.  I've felt this myself.   The problem is, if there is hydrocarbon contamination in the system, that heat can cause spontaneous ignition of the hydrocarbon.  The solution is to use non-hydrocarbon lubes, and compatible and clean materials, and then you will have nothing that can burn.

Below are some photos of my personal filling system.  I happened to own 4 cylinders.  Of the ones below, I own the larger 300cu.ft. bottles, but the smaller one is one I'm borrowing until I get one of mine back from retest, done every 5 years.  These cylinders can be rented from most any gas supplier, on a long-term lease, which is very affortable.  If you can fill 2 or 3 peoples Oxygen bottles off of these systems, and you use Oxygen regularly, you can almost definitely save money filling yourself.  In my situation, where I already own the cylinders, it's a no brainer.  Oxygen fills are $35 around here, and that's for just tiny cylinder full.  In comparison, I think the Oxygen fill for one of these 300cu.ft. bottles is about the same price...or maybe a couple bucks more, and it can fill many small bottles.  I also have to pay the $30 retest fee per bottle every 5 years, so there is that minor cost.  If you lease, you probably won't pay that cost, just the lease.   I will price out the transfiller hose below.

To fill an O2 cylinder, you would then use a "cascade" method.  Filling from the first cylinder to provide the bulk of the Oxygen, then moving to the 2nd to bring the pressure higher, and then the 3rd to bring it to the top.  I have 4 bottles now, but only plan to maintain a 3 cylinder Cascade system.   Then, when cylinder #3 is not able to completely fill the portable cylinder, you would shift them all down one spot, and get the emptiest one filled and put it in the highest slot.    This maximizes your use as best possible without an oxygen booster.

A Booster pump runs on regular compressor air, and pumps the air in the storage cylinder up in pressure to use it down to about 300psi, but still get 2200psi output for filling your portable.  It's the most economical way to go if you did tons of fills, but could be impractical for most anyone but an FBO.  For more info on boosters, go here: http://www.hiipumps.com and check out model 3G-SS-20-O.

Connecting and filling the cylinder is also easy.  I installed handwheel nuts on my fill whip, so you just run them down snug.  The nipples have a flexible tip to help it seal easily.  Then, you make sure the bleed valve is closed, and you open the valve on the portable cylinder.  Now you'll be able to read the pressure in the portable.  Without a gauge on the large cylinder, you will have to keep track of what pressure you left it at after the last fill.  If you have more pressure in the portable, it can backfill into the large cylinder.  This can be prevented by using an inline checkvalve, if you wish.   If the storage pressure is higher than the portable, then fill away...just open both valves slowly and let the pressure equalize over a couple minutes.  The portable bottle will get hot, if you don't go slow enough.  This probably it's much of a problem, but as the bottle cools, the pressure will drop and you will not end up with a full fill.  When the pressure has equalized, shut both valves, and then open the bleed valve to remove pressure from the line.  You need to do this or you can't remove the hose easily.   If the portable still isn't filled, then just close the bleed valve again and move on to the next cylinder and repeat.  It's very easy.  Make sure you check your portable bottles stamp so you don't exceed the rated pressure during filling.
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Pricing the Transfiller

I bought my Transfiller parts unassembled at the local Airgas store.  The parts are made by Western, and are readily available at most gas/welding supply outlets.  Here is what I bought:

Western Parts

Quan Part Description Price Total
1 PF2-4-48 Teflon/Stainless braid HP Hose - 48" $33.00 $33.00
2 WE 662P Handwheel Nut - CGA 540 $13.00 $26.00
2 WE 663 Soft tipped Nipple - CGA 540 $10.00 $20.00
1 WE 663-KPT Spare Nipple Tip $5.00 $5.00
1 BFT-4HP HP Brass Female T fitting $10.00 $10.00
2 B-4HP Brass 1/4" Male NPT to 1/4" Male NPT coupler $1.50 $3.00
1 217 or 211 valve 1/4" NPT Brass valve (can use others like Hoke 3712M4B) ~$20.00 ~$20.00