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O2 Cylinder Size

Auburntsts

Well Known Member
So I'm thinking about adding a 4-place O2 system, but I'm kind of stymied as to what size cylinder to get. For those of you that travel a lot, how often are you going up into the mid-teens at cruise? Currently I cruise between 8K and 10K so don't have a clue if climbing higher is something that would become routine or just be an occasional thing.
 
I'd be interested in knowing this as well. I guess there would be two reasons for me to get up to the mid teens - performance increases (taking advantages of winds, etc) and then I would imagine it would also allow you to get above most weather. Still have a long build ahead of me, but I'm looking forward to getting this puppy in the air.
 
It is so dependent on weather that it is imposable to summarize. I could go a year without hitting the teens, and then do it every flight for 2 months. Regardless, you will want the O2 for when you need it. I have a D size, and it is great for my 2 place. That would mean an "E" for a 4 place - if you really expect to have 4 often.
 
It is so dependent on weather that it is imposable to summarize. I could go a year without hitting the teens, and then do it every flight for 2 months. Regardless, you will want the O2 for when you need it. I have a D size, and it is great for my 2 place. That would mean an "E" for a 4 place - if you really expect to have 4 often.

Thanks! The E size (682L) was what I'm leaning towards under the "I'd rather have too much than not enough" theory. Plus I'd like to have as much time between refills as possible, mainly because I'm a lazy bast*rd. :D
 
Another reason to go bigger is that refill costs are not incrementally economical if you refill at an FBO - it's less expensive to fill a large cylinder occasionally than a smaller one more frequently.
 
I have the Mountain High system with the AL-682 cylinder. The pouch that comes with the cylinder straps to the top of the tunnel cover just behind the front seats. This makes it easy to snap in or out for refill, and for reaching back to turn on the valve.

We did a couple of long trips out west from Virginia with a lot of time at 14K' and 15K', two people. We used less than half a bottle for the round trip. I use O2 anytime over 8K'. There are three of us that share a charging station, each getting a O2 bottle from the local supply house ($40 for a full bottle). Three bottles provide a lot of charges for the AL-682.

Carl
 
Get the biggest tank you can cram in AND Mountain High's O2D2 proportionator.

I have the 647 tank in our -7 and my wife and I can cruise around the US without a refill. The O2D2 is the secret, effectively tripling the tank size. Pricey but worth it. We can suck a tank dry in 10 hours on oxymizer canulas. YMMV, your duration at what altitude defining your range. It's a huge and expensive inconvenience to find an FBO pumping O2.

Choose your altitude according to all the reasons we learned in ground school. No opinion on your operations.

John Siebold
Boise (MSA 12,000)
 
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I have the Mountain High AL-647 and the O2D2-2G for my RV7, I usually set it for O2 above 050 if I'm planning on flying above 080. The O2 seems to help with fatigue/feeling fresher upon arrival as well as longer intervals between bathroom breaks. So far I haven't come close to emptying the cylinder on trips of 12-15 hours.

For a little money up front you can fill your own bottle at home for a few bucks, on the road the facilities that can fill a bottle usually have expensive fuel and more hassle/traffic in and out not to mention the fill price.

The O2 is helpful for turning a headwind into a tailwind and getting above the bumps/clouds/terrain. It opens up more options when traveling cross country. Since I bought my system I've used it approximately 50% of the time.
 
Get the biggest tank you can cram in AND Mountain High's O2D2 proportionator.

I have the 647 tank in our -7 and my wife and I can cruise around the US without a refill. The O2D2 is the secret, effectively tripling the tank size. Pricey but worth it. We can suck a tank dry in 10 hours on oxymizer canulas. YMMV, your duration at what altitude defining your range. It's a huge and expensive inconvenience to find an FBO pumping O2.

I came here to say exactly this. I have the O2D2 and a CFFC-022 (carbon fiber, 22cu ft) cylinder. Anytime I go above 8k on any trip over an hour, I usually have it on. I got the four port regulator, so I can run an O2D2 for the front seats and another one for the back seats. I nestle the tank (in its bag) in between the two rear seats. It's close enough for me to reach back to turn it on and hook it all up while in flight.

Lots of advantages for this setup:
1. It's about 1/3 the cost of a built-in system.
2. The CF tank is feather light.
3. I fill that tank about 2-3 times a year. I built my own refilling rig so the refill cost is next to zero. I've yet to need to refill while away from home.
4. It's removable from the plane.
 
I got the four port regulator, so I can run an O2D2 for the front seats and another one for the back seats.

Aaron,
Do you have two O2D2 systems (one for front and back) or are you running one O2D2 up front and constant flow breathing stations in the back?
 
Aaron,
Do you have two O2D2 systems (one for front and back) or are you running one O2D2 up front and constant flow breathing stations in the back?

I have the Mountain High portable system with two O2D2 units. I think I have the D+ tank, but I have to look. I've flown six cross countries with it and there is still air.

The longer the distance, the higher I'll usually go if the winds are blowing the right way. I'm usually in the 10-15k range.

MH does have some good discounts during OSH. That's when I bought mine a couple years ago.
 
The O2D2 is key. I didn't want to spend the $$$, weight or panel space for the full on built in system. So I made a hybrid system. I plummed the plane for O2 with a remote regulator switch on my panel. I have one 02D2 in my center console (I can add a second, but for now, I have yet to have the need since the chances of me going a long high CC with 4 people are slim). I mounted the 647 bottle in the baggage compartment. I can get it out in about 20 seconds to do a refill. I had the bottle refilled last year at OSH and we have flown on about 6 long cross countries using the O2 and still have plenty in the tank. It's all about the O2D2.
I made a little pouch for the Regulator to store in. When I really need to save weight, I can pull the bottle. (Like when I had 3 navy seals in the plane on a flight out to the desert....)
 
Definitely go 682 on the cylinder. Especially if you ever may use it for 4 seats. I may even suggest that for a 2 seater. As people have said, cheaper to fill in the long run, and I hate being O2 limited on long x/c flights in the summer when staying up above the bumps.
 
flat fee for bottle fill

Another reason to go bigger is that refill costs are not incrementally economical if you refill at an FBO.
That's exactly correct. At my FBO they charge a flat $50 no matter what size cylinder. Due to weight considerations, I have only a 1 Outlet, 9 Cu Ft Cylinder in my plane.
 
Aaron,
Do you have two O2D2 systems (one for front and back) or are you running one O2D2 up front and constant flow breathing stations in the back?

I have two O2D2 Units. One for front and one for back. That gets all four of us O2 when needed or desired.
 
I definitely recommend the largest tank you can install. I have a -9A, routinely fly in the 13.5-14.5 altitudes on cross countries, and have two E-bottles with 2 oximisers. I have painfully noted that those airports with O2 available tend to have turbines and jets parked on their ramps with fuel and O2 prices to match. Dan from Reno
 
I have an E bottle with the Mountain High EDS system in my 9A and absolutely love it. The longer wing and Roncz airfoil on the 9 loves a high cruising altitude and I routinely fly in the mid-teens for cross country trips. I fill my own tank at home and with the E tank I have not needed to fill on the road yet.
 
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