Hi there.
I'm building an RV10, which has something of a sweet spot for flying at oxygen-recommended or required altitudes. But having never flown with oxygen before, I'm wondering how refills are typically handled at FBOs.
Two options I have are either a portable system or one built in. I like the idea of having one built in, and there are some apparent nice systems available. The decision on which to use, however, will be based in large part on its practicality. Is it relatively common to find FBOs with oxygen available (at least, in mountainous provinces/states)? And where it is available, do they bring it out to the plane along with a fuel truck, or is it more common to have to haul a portable cylinder inside where they fill it there?
Obviously, if it's relatively common to refill oxygen on the ramp at FBOs, a built in system could be very convenient. But if it's more difficult to find, and often the bottle needs to be hauled around anyway, a portable system might be more practical.
For built in systems, I've seen two styles of filling ports - a 3/8-24 and a 9/16-18. Is one more common than the other?
At my hangar, of course, I can rig up a filling system that works in either scenario. I'm more concerned with what I'll find more readily available while away from home.
Thanks for any help and advice!
Dan
Portable vs Built in oxygen systems
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Re: Portable vs Built in oxygen systems
To answer your questions:
1. Availability - Generally good where ever you have a full service FBO. If there is not one, you are likely going to have to source it from an industrial supply (Air Liquide, Airgas, etc.) instead. So outside larger centers, do not plan on being able to get it easily. I've had to rent and truck cylinders to more remote locations in the past to ensure supply...
The FBO can usually bring it to you or take your tank in. Most have a cart that has the cylinders on it, somewhere between two and six for cascade filling. Doesn't really make a difference either way to the FBO usually. I take mine in because they are not built in. Portable is a bit less of a pain than obtaining certification for a permanent install in the aircraft. I would say go for the former if you can. Then again because you have a home built it might not be much of a hassle to install as a certified aircraft.
2. Port sizing - The 3/8-24 threaded fitting is the most common (aka MS22066 & MS220353). 9/16-18 thread (aka Scott/Airline) is not exactly uncommon either, but is less available in general. That said, most transfilling rigs will come with adapters for both. The other option is CGA 540. That is used on the outlet of most tanks, like those from Mountain High, Aerox, etc. That is by far the most common because it is the standard for O2 tanks (at least in NA, DIN-477 in Europe). A simple male to female adapter will allow you to fill from any available oxygen tank.
As stated above I would go with a CGA-540 based portable system. Get the CGA-540 transfill line with it and you are good to go, literally anywhere. Mountain High is my brand of choice because they offer the O2D2 as well. It is an electronic on-demand system that only supplies O2 when you breathe in. While pricey at ~$800, the O2D2 will save you a ton of cash on refills over its life. It can dramatically reduce your consumption by up to half depending on altitude. It can automatically adjust flow rate based on altitude as well, making it both miserly on the O2 and easy to use... Turn it on, put on cannula and forget it.
1. Availability - Generally good where ever you have a full service FBO. If there is not one, you are likely going to have to source it from an industrial supply (Air Liquide, Airgas, etc.) instead. So outside larger centers, do not plan on being able to get it easily. I've had to rent and truck cylinders to more remote locations in the past to ensure supply...
The FBO can usually bring it to you or take your tank in. Most have a cart that has the cylinders on it, somewhere between two and six for cascade filling. Doesn't really make a difference either way to the FBO usually. I take mine in because they are not built in. Portable is a bit less of a pain than obtaining certification for a permanent install in the aircraft. I would say go for the former if you can. Then again because you have a home built it might not be much of a hassle to install as a certified aircraft.
2. Port sizing - The 3/8-24 threaded fitting is the most common (aka MS22066 & MS220353). 9/16-18 thread (aka Scott/Airline) is not exactly uncommon either, but is less available in general. That said, most transfilling rigs will come with adapters for both. The other option is CGA 540. That is used on the outlet of most tanks, like those from Mountain High, Aerox, etc. That is by far the most common because it is the standard for O2 tanks (at least in NA, DIN-477 in Europe). A simple male to female adapter will allow you to fill from any available oxygen tank.
As stated above I would go with a CGA-540 based portable system. Get the CGA-540 transfill line with it and you are good to go, literally anywhere. Mountain High is my brand of choice because they offer the O2D2 as well. It is an electronic on-demand system that only supplies O2 when you breathe in. While pricey at ~$800, the O2D2 will save you a ton of cash on refills over its life. It can dramatically reduce your consumption by up to half depending on altitude. It can automatically adjust flow rate based on altitude as well, making it both miserly on the O2 and easy to use... Turn it on, put on cannula and forget it.
Re: Portable vs Built in oxygen systems
Thanks a lot for your detailed response!
With a homebuilt, certification isn't an issue - the issue is just how to set things up for the most convenience. That's why I've been leaning away from a portable system... I like the idea of tanks being out of sight, if it's practical.
I called a few FBOs around the area and it does seem that the ones who supply oxygen are used to filling it from the cart at the plane. They've said they have adapters to work with most fittings, but it's great to know that the 3/8-24 fitting is the most common. If I have to choose on a fitting, I'd rather try to make things as universal as possible.
Whatever system chosen, you're right - the pulse demand concept really does seem to be the way to go. And at the rates for filling cylinders at most FBOs, it wouldn't even take that long to pay for itself
Dan
With a homebuilt, certification isn't an issue - the issue is just how to set things up for the most convenience. That's why I've been leaning away from a portable system... I like the idea of tanks being out of sight, if it's practical.
I called a few FBOs around the area and it does seem that the ones who supply oxygen are used to filling it from the cart at the plane. They've said they have adapters to work with most fittings, but it's great to know that the 3/8-24 fitting is the most common. If I have to choose on a fitting, I'd rather try to make things as universal as possible.
Whatever system chosen, you're right - the pulse demand concept really does seem to be the way to go. And at the rates for filling cylinders at most FBOs, it wouldn't even take that long to pay for itself
Dan
Re: Portable vs Built in oxygen systems
I found that many FBO's will fill from a gang of bottles rolled out on a cart which may mean you will not always get a full bottle when you want a fill. They are all a pressure equalization system so you get whatever pressure they have in the fullest supply bottle.
Ask the FBO's if they fill with a pump. The last place I worked at had a pump, run by shop air or an on-board nitrogen bottle that could fill the airplane bottle to the full 1850 psi, regardless of the pressure in the supply bottle. Some may not have the pump because they are an expensive little sucker.
Ask the FBO's if they fill with a pump. The last place I worked at had a pump, run by shop air or an on-board nitrogen bottle that could fill the airplane bottle to the full 1850 psi, regardless of the pressure in the supply bottle. Some may not have the pump because they are an expensive little sucker.
