Inexpensive Oxygen Fill Cart

[GLDAS]

Also as an alternative to creating/operating your own filling system, using the Mountain High O2D2 pulse-demand system adapted to our plane's built-in O2 system (with a $250 pressure regulator that plugs into any one of the plane's outlets), 2 people flying in the plane each consume only 1/3 as much O2 as before and thus we only need to refill the plane's tank 1 or 2 times/year. (The O2D2 also has the huge advantage of automatically regulating each user's individual O2 consumption based on altitude so you're not repeatedly adjusting O2 levels while in flight.) So for us the typical $80/fill by an FBO isn't that often.

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I've come to the same conclusion for my plane after visiting with Mountain High at OSH this year. The transfill hardware is $6-700 for a two tank system, plus maybe a hundred for a cart and $200 for tank rental. The O2D2 tapped into the factory system looks like a winner, both in terms of conserving O2 and cutting down on the drying, constant-flow of oxygen.

So, while I have plenty of hangar space, the expense and hassle of filling my own vs two $100 refills and $1000 of O2D2 and associated stuff pushes me towards the latter.
-dan

[carym]

I appreciate the convenience of having built in oxygen, but I swore I would not have built in oxygen in my plane many years ago. I had built in oxygen in my C310, but when it came time to refill the tank I found that the DOT required the tank to be hydrostatic retested every 5 years and the FBO wouldn't fill it without that recert stamped on the tank. The cost of removing the tank from the plane, sending it out to get it recertified, and then re-installing the tank was so much greater than just buying a portable tank, that I went to the portable tank route after that. That is why I didn't get built in oxygen in my DA42. To fill the portable tank at my local oxygen supply house is only about $25. The 5 year recert at the local supply store was only $45. My local FBO wanted $100 to fill the tank, and when I needed my portable filled at KPVD the only FBO there that would fill oxygen (built in or portable) wanted $250! I still think that using a portable system has more advantages than disadvantages. For those thinking of buying a plane you should consider these points.

[Colin]

My record was at KPDX. They wanted $350 to fill my little portable O2 bottle. They said they'd have to call out a mechanic to the field to do it.

[ultraturtle]

The hassle and cost savings for oxygen supply is a separate issue from the cost savings of oxygen use. I chose to save both on the supply end by purchasing and assembling my own fill cart, and on the consumption end by using the Mountain High O2D2 Pulse Demand Regulator.

I'm not knocking the Mountain High system, but would like to point out that you may not be saving as much oxygen as you think. The factory Oxysaver cannula gets 32 hours of single user duration at 18,000' (5.3.13 of AFM Supplement S04 http://support.diamond-air.at/fileadmin ... S04-r0.pdf).

This is almost identical to the 32.7 hour duration of a single user of the Mountain High O2D2 from a 50 cu ft tank at 18,000' (http://www.mhoxygen.com/index.php/compo ... wnload/627).

Both use less than a quarter of the oxygen of a standard cannula, however (7.4 hour single user duration at 18,000').

The real advantages of the Mountain High system to me are more about comfort and safety than cost:

• The O2D2 cannula is far more comfortable than the Oxysaver cannula.
  The amount of oxygen adjusts automatically with altitude.
  The puff of gas at the beginning of each inhalation provides constant feedback that you are getting oxygen.
  The O2D2 regulator gives an audible warning tone if you skip a breath or two, reminding you to breath through your nose.

[Colin]

My understanding was that the O2D2 also changed the flow on the climb so that if you were at 9,500 (which I often am to avoid headwinds) but still on O2 (which I am, because it reduces my fatigue), it is much more efficient.

[ememic99]

My understanding was that the O2D2 also changed the flow on the climb so that if you were at 9,500 (which I often am to avoid headwinds) but still on O2 (which I am, because it reduces my fatigue), it is much more efficient.

Basically yes, O2D2 modifies flow with altitude by changing frequency and duration of oxygen pulses.

[Carl]

Guys,

Couple of brief comments....

1. I have been using 02D2 in my Columbia 400 since 2007, excellent system which is altitude-compensating. Does wonders for increasing my oxygen endurance especially since the 400 came standard with a built-in 42 cu ft system (increased to 77 cu ft in the TTx). I typically fly in the high teens-low 20's and get 32-40 hours of oxygen between refills (which are $65 in San Diego).

2. For solo pilot operations below FL180, have any of you considered purchasing an oxygen concentrator? Yeah, pricy (but what isn't when it comes to airplanes?) but at the very least you know you can always get O2 when you need it. Aviation Consumer did an article on them a few months back, I've been considering one of the Inogen models.
-Carl

[ultraturtle]

But with two unmodified carts you could have four tanks...

True, but there would be no safe way to cart them to the aircraft nose without removing, then replacing the manifold for two of the tanks. Not only a bit more time consuming, but potentially a bit more explodey should carelessness prevail.

A single cart three tank system requires a single valve disconnection and reconnection only once every tank swap out, roughly every 3 fills. A two cart, 4 tank system would require up to 4 valve disconnections and reconnections every fill, roughly 10 times the opportunity to blow the roof off of your hangar should you catch a bit of grease on one of your tank wrenches.