JoshK

Excellent point. The new portable came oxygen clean and ready for fill.

Following back on this now that everything is here for a test fill I started with a bone empty 15ft portable cylinder and empty 115ft tank in the Rocket The links to the whip and adapter that are in this thread work perfectly and the parts arrived in about 10 days all total. I used 200ft Oxygen cylinders for the first fill, I will swap to 300’s when I swap them (same price, local place didnt carry 300’s so they’re special order) First stage starting at 2300 psi brought the A/C tank to 1400psi. Then 1400 in the first stage brought the 15ft portable up to 1150ish Second stage starting at 2300 brought the A/C to 1750 where I stopped it. Bottle still has 2000 in it. I topped the portable up to 1750 as well and near as I can read the gauge I think stage 2 is 1850-1900 I didn’t touch stage 3 yet The system is kludgy right now, I have to make the time to build a rolling rack. Bottles are currently stored laying down and chocked into a corner. When in use I stand one up and strap it to a hand truck to stabilize it while filling. I will refine more as I fill more however I think the following is my go forward: Get the 300ft bottles to start A single bottle isn’t bad but 2 is better, looks like 3 will be optimal for a hangar setup for a single airplane. The Aviation adapter for CGA540 to Scott 9/16-18 is substantially more expensive than buying the fittings off Amazon and assembling yourself. No surprise, I just didn’t know the fittings were standard so I pod the $205 or so for an aviation one instead of a welding supply one. I am looking for an off the shelf solution now online, I can find one that comes preassembled I will post it. Other than that, everything else is off the shelf sourced from Amazon. This is easy. Fill slow, be clean and careful, and you can be independent on your oxygen. Sent from my iPhone using Tapatalk

Excellent points. All in all the cost of the oxygen system in hangar is still pretty low whether we are renting or buying. Compared to paying for fills at another FBO I will have the annual rental amortized in 1 fill and the overall cost of the other extemporaneous pieces amortized in 2 more since I didn’t buy the tanks. Sent from my iPhone using Tapatalk

Rent/lease only for 200 and 300ft size tanks. I should have been more clear: Keen is very local (under 2 miles) to my business and rents only for sizes over 80ft. Airgas doesn't answer their phone but when I walked in they wanted a higher rental rate and larger deposit than Keen, they only rent for sizes over 125ft. They're about the same distance from the airport but much farther from my business address. Both will swap for you but they won't take a tank on swap that needs hydro without billing you for the hydro cost. Cost of a fill from Keen is $25 for a 200 or 300 ft, Airgas was similarly priced for 200 and was $10 more for 300ft. Wilson Products will fill while you wait if you want, they sell 200/250/300ft and they're a 3 hour drive round trip. Fills were expensive, about $90. For now I'm just going to rent the 3 tanks and see how things go. I can always buy tanks over time and drop off the rentals as I acrue my own.

That is superb Sent from my iPhone using Tapatalk

Keen is the only place I found locally. They have a bunch of locations in this area because they have a plant about 30 miles away as the crow flies. Wilson products was more than happy to work with me however I wanted but their closest facility is 90 minute each way. The drive time inconvenience is pretty high. The convenience of Keen is great, they’re 3 min away from my business. They are just being a pain to deal with. Sent from my iPhone using Tapatalk

They mitigate that by telling you to rent. Sent from my iPhone using Tapatalk

Maybe 20 years ago they were $120 but then again everything is substantially more expensive now so I don’t doubt it. If I wasn’t told specifically I was responsible for the hydro I probably would have swallowed the pill and bought the tanks right now. As it stands the rental cost amortizes on a 5-6 year plan vs owning. Sent from my iPhone using Tapatalk

That’s what the local supply place told me when I asked about renting or swapping my own tanks instead of waiting for a full. I asked specifically what happened if I got a tank back that was coming up on hydro and they said that on rentals they handle it always. If I own the tank when it comes back they will swap it but I pay a hydro fee. Sent from my iPhone using Tapatalk

That’s a pretty good arrangement. Around here the local conglomerate is Keen. They don’t sell anything bigger than 80 ft in Oxygen… Sent from my iPhone using Tapatalk

It’s a double edged sword Hydro on a steel industrial tank is good for 5 or 10 years, I forget which right now. If you buy a brand new tank it comes with a new hydro from this year. If you go to swap it you’re going to get back some beat ass POS with a total roll of the dice on when it was hydro’d last If your next fill comes after the time when the exchange tank comes due for hydro they’re going to stick you with the bill for hydro even though you swapped them a new tank 3 months ago. Over 5 years it costs the price of the tank to own it in rent. Ultimately if I’m using them at a pace where it makes sense to own I can always buy tanks and tuen in my rentals. Sent from my iPhone using Tapatalk

I looked into buying like this, this is a good price. Shipping is via freight and it's costly. I have a freight dock at my shop so that isn't a problem but it was basically "pay for 4 bottles get 3" when shipping is factored in. The local gas supply houses by me will not fill a customer owned tank, they will only swap it. The nearest place I could find that would fill while I waited was almost a 90 minute drive each way. I decided to rent 3 bottles as I negotiated the price for 300cuft bottles to the same rental fee and fill cost as 200ft bottles since they only stocked 200's and I'm a local business. The cost to rent was $66/yr, they waived the deposit (again, local business) and the tanks came filled. With buying 3 tanks, shipping them here, then paying for a fill at the place 90 minutes away and driving back again I penciled it out that I needed to do a lot of filling before it made sense in money/time/hassle to own vs. rent. The CGA 540 to Scott adapter arrives whenever MH Aviation decides to ship it. The rest of the stuff is either on my loading dock or in my hangar already. Total cost for a 3 tank cascade for 1 year appears to be right about $500. Next year that price will be around $300 since I don't need to pay for the transfill and whip a second time. All in all that's pretty reasonable as compared to the cost to hop to a neighboring airport and spend half a day for them to fill it up for $125 plus tax. Convenience alone I would pay $500/y just to be able to do it myself.

A simple welding gas cart is all you need. And every weld supply, harbor freight, and Lowe’s carries welding carts that hold 2 bottles (oxygen and acetylene) but nothing says you can’t put to O2 tanks on it instead of O2 and C2H2 Many thanks to you guys, I cropped down the system assembly costs by about 8x total. I ordered everything tonight and ought to have a small cascade in my hangar within 2 weeks Sent from my iPhone using Tapatalk

Where did you get the CGA 540 female female whip? Did you make it? I spec’d a Haskell out as part of the system my buddy was helping me with. By the time he got done it was touching on 10 grand for the way he suggested building it. I had to remind him “this isn’t for a 9-9’s electronics facility” Sent from my iPhone using Tapatalk

Awesome write up, thank you!! @apache64 thank you for the comments on the portable whip too. I appreciate it Sent from my iPhone using Tapatalk

175/6@ 13,5 172/3 @ 11,5 ETA: Sorry, that was TAS. 150 IAS Sent from my iPhone using Tapatalk

Definitely ROP, which works but you could save fuel. This was 13,5 yesterday cruising along NC and VA Sent from my iPhone using Tapatalk

Would you mind posting a photo of your system in the hangar? Fills are indeed a PITA and I am in the midst of doing it myself. I have a 4 stage cascade system spec’d but it’s on the costly side. A friend of mine who works in the compressed gasses industry helped me do it… I’m pretty sure you could fill the space space shuttle with the hardware he specified. Sent from my iPhone using Tapatalk

Cannula are not legal above 180 The mask is good til 250 A different masking required for 250-400 Sent from my iPhone using Tapatalk

https://preciseflight.com/product/a5-boom-cannula/ https://www.mhoxygen.com/product-category/cannulasface-masks/cannulasface-masks-e-z-breathe/ https://aithreaviation.com/products/aithre-boom-cannula-preorder I decided to go with a mask from Aerox. Even for use below 180 I found it more comfortable than the way the cannula felt and it gives me the option to go to 250 if I needed to without descending, switching Oxygen hardware, then climbing back up. I have Cannulas (cannulae?) on board for all 4 seats but only my older son has any interest in wearing oxygen. If all 4 of us are onboard then I keep it below 10k as my wife is not comfortable with using supplemental oxygen. @pinecone good article, well done Sent from my iPhone using Tapatalk

Oh for some reason I had it mind that you did. Either way the 231 is pretty damn fast on its own. A good friend has one with the various updates and mods for speed and altitude. He said 200-210 are his best altitudes. He has gone to 230 but with the extra heat generated he wasn’t going as fast due to more drag from the cowl flaps and extra AOA. Yeah, the Rocket is thoroughly amazing to me. I couldn’t be happier with it Sent from my iPhone using Tapatalk

Is your Rocket a 231 conversion? The 252 Conversions are 28k SC's Both of them are guaranteed to have CA's at 23k per the Rocket manual, which gives pretty incredible performance at FL240. Recently I took mine from GRB to MQS at FL230 and a 40kt push in well a little over 2.5 hours. It loves to be up high.

CA is that point at which the turbo can no longer maintain sea level rated power at the given altitude at full throttle. Service Ceiling is where the plane can no longer maintain 100fpm climb rate. I am not too familiar with the spec on the original 231's however as I looked hard for a Turbo Arrow 3 for a while I can tell you that turbo Arrows were originally made with a fixed waste gate and no intercooler, giving them a critical altitude of 12,000ft MSL and a functional service ceiling in the low 20's, around 21,000 IIRC. Bootstrapping was a major concern for them just like people talk about the early 231's. Someone, I believe Merlyn, made an intercooler and automatic wastegate STC for it that brought the CA to 19k and solved the overboosting problem which gave the early tArrow's a huge bump in capability as well as easier engine management for less experienced (and tired) pilots. Personally having flown 2 people and 50gal on board (72 total allowed) to 21,000 at a 800fpm climb rate all the way to FL180 I was blown away at the performance compared to my N/A Arrow 3 under the same kind of loading. This solidified wanting a turbo-something for my next airframe. I just happened to find a Rocket first... I'm not disappointed

Good datapoint, thank you. Here’s another you might try that I have been really liking lately for just cruising along in no particular hurry… though in a Rocket it’s still ~40kt faster than the Arrow I came out of [emoji16] It’s LOP for sure, and this is at 11,500 with the cowl flap closed completely. True at 171/172kt I was sent a photo from a friend recently that makes me think my main gear doors need to be re-rigged which I suspect will improve speed several knots from talking to Marauder. If his estimates from his F model experience are anything to go off then deriving the gear doors might push me closer to 180 than 175. Sent from my iPhone using Tapatalk

Makes sense. My Rocket is a 252 based conversion, and I do exactly what you describe: tune in the cowl flap position to react to temps. With me and standard fuel load it climbs at 375-380F CHT on the hottest cylinder until the upper teens at a constant rate climb but I’ve started using a constant airspeed climb above 14k to keep things under 380. That turns into hand flying and/or tweaking the programmed climb rate on the old King AP to keep it where the airframe seems to like the airspeed. Sent from my iPhone using Tapatalk