Mountain High for Built-In Oxygen System

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NickBudd
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Re: Mountain High for Built-In Oxygen System

Post by NickBudd »

Sure Russ I am planning to use the plane this week so will take a photo and post it. But if you look at the nose compartment of any DA42-or I suppose 62 with factory 02 you can see the cradle and strap arrangement.
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Boatguy
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Re: Mountain High for Built-In Oxygen System

Post by Boatguy »

NickBudd wrote: Tue Jan 04, 2022 6:42 am Sure Russ I am planning to use the plane this week so will take a photo and post it. But if you look at the nose compartment of any DA42-or I suppose 62 with factory 02 you can see the cradle and strap arrangement.
Yes. I was confused by the two lines from the bottle. My MHO2 first stage only has a single hose, which then goes to the 2nd stage / controller which has two lines.
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Re: Mountain High for Built-In Oxygen System

Post by photoSteveZ »

ememic99 wrote: Wed Dec 29, 2021 12:04 am IIRC it’s on average 30 psi/h/person from built-in O2 tank using O2D2.
That seems high; I estimate it's roughly half that. I filled the built-in tank to 1800psi 170 flight hours ago. I use oxygen for one or two people on nearly every flight and still show 750psi in the tank. Of course, the 62 has a larger bottle, but even so...
Last edited by photoSteveZ on Wed Jan 05, 2022 4:01 pm, edited 1 time in total.
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Re: Mountain High for Built-In Oxygen System

Post by photoSteveZ »

Boatguy wrote: Wed Dec 29, 2021 12:01 am
photoSteveZ wrote: Tue Dec 28, 2021 11:14 pm For the new '62 I'll take delivery of in two or three months (fingers crossed!) I've obtained a second 02D2, for some planned 3- and 4-passenger touring. It's nice not having to worry about filling the ship's oxygen tank but once or so a year.
How do you mount the O2D2? Does it just hang from the adapter?

Caution - thread drift: Why a second DA62? Selling the first or building a fleet?
Yes, the step-down regulator just hangs from the overhead, and I keep the O2D2 velcroed to the carpet on the aft side of the spar carry through, below the second row air vents.

Nipping thread drift, I've answered the latter question in the DA62 forum just this morning. :)
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Re: Mountain High for Built-In Oxygen System

Post by ememic99 »

photoSteveZ wrote: Wed Jan 05, 2022 3:54 pm
ememic99 wrote: Wed Dec 29, 2021 12:04 am IIRC it’s on average 30 psi/h/person from built-in O2 tank using O2D2.
That seems high; I estimate it's roughly half that. I filled the built-in tank to 1800psi 170 flight hours ago. I use oxygen for one or two people on nearly every flight and still show 750psi in the tank. Of course, the 62 has a larger bottle, but even so...
Depends on altitude, I practically always fly somewhere between FL160 and FL180.
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Borealis
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Re: Mountain High for Built-In Oxygen System

Post by Borealis »

The difference between the Mountain High (MH) system and using the supplied Aerox Oxysavers might not be so high.

According to the AFM supplement for the built-in oxygen system, the duration for one person using the Aerox oxysaver cannulas on a full (50 cu ft) tank is 60 hours at 10.000ft, 50 hours at 15.000 ft and 32 hours at 18.000 ft. (Using standard cannulas or a mask it is 20,3h, 16h and 7,4h respectively, which obviously is much less).

And looking at the cylinder duration chart at Mountain Highs webpages they have a bottle that take 48,2 cu ft., that will last respectively 83,6 h, 40,5h, 31,5h at those altitudes. This bottle will fill to 2216 PSI and not 1850psi like the built in tank in the DA42. However, they also have tanks that fill to 1850psi, but at other volumes. But extrapolating those volumes to 50 cu ft. give roughly the same numbers - 86,8h at 10.000ft, 42h at 15.000ft and 32,7h at 18.000ft.

It seems a bit strange - but according to the published tables the MH EDS give a longer duration at 10.000ft, a lower at 15.000ft and about the same at 18.000ft.

If this is correct it might not be worth the hassle and money to have an MH O2D2 in addition to the built-in system provided you use the Aerox oxysavers...
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Re: Mountain High for Built-In Oxygen System

Post by CFIDave »

Borealis wrote: Thu Jan 06, 2022 7:51 pmIf this is correct it might not be worth the hassle and money to have an MH O2D2 in addition to the built-in system provided you use the Aerox oxysavers...
Except that the MH O2D2 automatically adjusts O2 delivery based on your pressure altitude. No need to mess with needle/ball valves for each person.
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Boatguy
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Re: Mountain High for Built-In Oxygen System

Post by Boatguy »

Borealis wrote: Thu Jan 06, 2022 7:51 pm It seems a bit strange - but according to the published tables the MH EDS give a longer duration at 10.000ft, a lower at 15.000ft and about the same at 18.000ft.
Are you sure you are reading the table correctly?
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Re: Mountain High for Built-In Oxygen System

Post by Borealis »

Boatguy wrote: Fri Jan 07, 2022 1:40 am
Borealis wrote: Thu Jan 06, 2022 7:51 pm It seems a bit strange - but according to the published tables the MH EDS give a longer duration at 10.000ft, a lower at 15.000ft and about the same at 18.000ft.
Are you sure you are reading the table correctly?
Reasonably sure yes. If you look at the greened out line in the table you copied in for the AL-415 bottle, it has a capacity of 14,7 cu ft of oxygen and lasts 25.4h at 10.000, 12.3h at 15.000 and 9.6h at 18.000. In order to extrapolate those numbers to a 50 cu ft bottle i multiply everything by 3,4 and that renders the same number that I used above - around 86h at 10.000ft, 42h at 15.000ft and 32h at 18.000ft. I am open to that this might not be a correct way to do it, but it seems the logical way to be able to compare this information with what is published in the AFM supplement for the built-in system.

CFIDave has a point though that the MH is easier to "set and forget". But it seems if you are using oxygen more at 15.000 ft + altitudes than 10.000ft, then it will actually not last longer.
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Re: Mountain High for Built-In Oxygen System

Post by Boatguy »

My point was "about the same" from 15,000' and 18,000'.

However, your extrapolation is confirmed by the table if you use the CFFC-048 line for a 48.2 cu ft bottle.
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