Old/New CO2 system still available?

[thor]

I would use a high volume low pressure pump exactly like Andy kindly pointed out , then add a propel back up system as a failsafe. Are you not seeing my earlier responses to your questions?

I would not trust my life to a Co2 flask made in China.

Jeff,

After the incident with Gene Berger, didn't the EC ban the use of high pressure systems from SC events for insurance and safety reasons?

I design high pressure gas, fliud, and process equipment for a living. Mostly ASME Section VIII, Div1, Div 2, and Div 3 pressure vessels. I wouldn't want to be within a mile of a Co2 system built by anyone who isn't highly trained and fully certified.

[sgtmac1]

I would use a high volume low pressure pump exactly like Andy kindly pointed out , then add a propel back up system as a failsafe. Are you not seeing my earlier responses to your questions?

I would not trust my life to a Co2 flask made in China.

Jeff,

After the incident with Gene Berger, didn't the EC ban the use of high pressure systems from SC events for insurance and safety reasons?

I design high pressure gas, fliud, and process equipment for a living. Mostly ASME Section VIII, Div1, Div 2, and Div 3 pressure vessels. I wouldn't want to be within a mile of a Co2 system built by anyone who isn't highly trained and fully certified.

I'm not trying to be snide but certainly the SC hasn't banned Jim Butt's Batfish from any meets and people still sell systems and parts of systems to use co2, don't they? Using your logic, no one outside of an auto design lab can be trusted to work on your car, whereas I routinely change everything in my car such as lower control arms, struts, engines, rearends, etc. without benefit of degree or formal education in car mechanics. Very few people have that knowledge. I am attempting to learn about the application of co2 ballast systems that have been used in dozens of r/c submarines, the likes of which I have been reading about in the SCR for more than 20 years. I appreciate your concern and I am trying to learn from you and everyone else how these systems work, the pitfalls to avoid, and lessons learned. What I would like to do is use the experience of this group to have several working subs. I have been consulting Jim on his boat and feel there is a reasonable alternative to pumps, snorkels, rscabs, rehabs, whatever that is being tried and discarded, it seems on a quarterly basis. Everybody has strong feelings on what works best, and it seems especially so in the SCR.
Also, my join date listed is for when I resumed membership in the Subcommittee in 2014; I began receiving the SCR back in the early 90's and left for two years when the SCR went all electronic...

[thor]

I am not trying to be snide either. I am simply trying to communicate that these systems can be extremely dangerous in the wrong hands, and even in the hands of an experienced person they can still bite you.

Working on your own vehicle, or even altering its design, for what ever reason, is not regulated. Altering high pressure gas system designs or components is regulated. Where is the logic in that? I have no idea...

As for the Co2 systems being banned from SC events, I am asking Jeff an honest question as I remember there was a discussion surrounding the banning of HP systems after Gene Berger planted his wrench collection in the ceiling of his garage. I do not know if it was ever followed through.

I am very interested in what you found for pumps. Please post what you find? That can be most helpful.

[Guest]

I've demoed a few diaphragm pumps, and generally they tend to reach pressures between 6-15 psi, with the upper range reached by the bigger pumps. You can increase pressure by connecting pumps in series, but I would say you're better off with a piston based pump for higher pressures.

I think systems like Co2 were explored more when small pumps were difficult to come by, or you needed machine tools to adapt other designs to make them work well in a model submarine. Propel based systems would be quite expensive to run in a large model, so I guess C02 was considered a viable alternative.

Personally I prefer low pressure systems from a peace of mind perspective, and I also favour systems that don't rely on consumable gas. Piston tanks get my vote, as they allow very accurate trimming of the boat, operate at low pressure, and are easy and inexpensive to maintain. However to make your own does require access and ability to use a lathe, and that puts a lot of modelmakers off.

Commercial units (engel, R7R etc.) restrict you to certain sizes and volume, although there is growing variation on the market nowadays.

[apa-228]

It seems to me that you have made up your mind that the CO2 system is the way to go and are looking more for confirmation than advice. As you know, there is a wealth of knowledge available here and the warnings about the CO2 systems are valid. The decision is yours and as the saying goes "you pays your money and takes your chances". Good luck with your sub which ever way you decide to go.

[bigdave]

I don't think Co2 was ever banned from SC events but the filling of tanks was, as is Propel actually.
Only designated areas away from the populis can be used for filling.
Jim would know for sure on the Co2.
Please don't think we are trying to be snide.
Just trying to inform you of a definite concern.
In my 35 years of building RC subs I have come to the conclusion the best all around system would be a light weight piston system. But sadly light weight and pistons don't usually go together. As most are dry boats. No free flood areas.
My little Engel 212 weights a ton.
But it is a SWEET running sub.
But you can't beat a piston system for operation.
As a matter of fact I can tell you there is an article in the up and coming SCR done by my good friend DonO.
Is is on putting a (piston/cylinder) in the Moebius Skipjack.
A piston tank inside a cylinder.
And don't stop asking questions. Even if you don't like the answers, or feel we are being snide.
I like to say there are never any stupid questions, just stupid answers. BD

[sgtmac1]

I appreciate everybody's viewpoints, it's how we learn what goes on outside of our own narrow little views. Per one of the suggestions given, I ordered 3 different water pumps so that I could start experimenting with those ballast systems. It could possibly lead to a much better set up.
Thank you.

[JWLaRue]

Matt,

What I recall is that the SC requires that all filling/venting activities dealing with compressed gas (both high and low pressure) be done at a specifically-designated 'filling station' that is to be located away from the everyone....spectators as well as the other modelers.

That said, I fully echo those previously posted warnings about the danger involved with using a high-pressure system like the CO₂ systems being discussed. If you are not already familiar with the technology and how to safely use it....you would be well advised to not do it. Jim Butt (and his fleetboat) is an excellent example of someone who does have a background in this technology that leveraged that knowledge in building his ballast system. So calling his use of CO₂ out as a reason that it's okay is not valid.

-Jeff

[thor]

Thanks for the clarification, Jeff! I couldn't remember what the final outcome of that discussion was.

[southern or]

Engel's makes piston tanks from 250ml all the way up to 1,000ml and people have been putting tanks in tubes. My Oscar and Typhoon are both going to use 2 tanks, but they're a lot bigger and use a completely different WTC. Still though, the tanks will go from full to empty in well under a minute.

Speaking of gas powered happy fun time, did anyone ever work in HALON "protected" room with a sign that reads, "DON'T PULL YOU'LL KILL US ALL"? Fun times.

[sam reichart]

Jeff LaRue needs to show you his system that he employs in his OTW Seehund.

[bigdave]

We built Don's cylinder for his old Albicore about 18 years ago.
He updated it for the Skipjack.
BTW Jeff's piston inside the modified OTW cylinder is very nice.
Although he stole the Dial-A-Depth from me!
Hi Jeff! Knee! BD

[subdude]

Guys,

1. At official SubCommittee events, the filling of ANY gas container is to be done at a "filling station" away from other people. Personally, I don't even use that, I fill the co2 tank for my fleet boat in the parking lot, away from everyone and everything.

2. I also will go on record as recommending that co2 not be used as a ballast control system unless you are highly experienced in the use of high pressure gasses and their containment systems. The tanks must be re-certified regularly by hydrostatic testing. It's serious stuff.

Frankly, the longer I am in this hobby (and it's been a few weeks now ;-) ) the more I am drawn to piston and pump systems. They are far more reliable and safer than gas systems, and don't require refillable resources other than amps in the batteries.

[thor]

Guys, not to get too far off topic, but I will be introducing an all new light weight piston design that is incorporated into the WTC, not as a piston cylinder inside of another cylinder. This piston is integral, and "floats" along the I.D. of the cylinder. There are no jack screws or anything of the sort that protrudes into the inner workings of the cylinder.

So far, the tests have all been extremely promising. I should have it operating fully after the first of the year. The "Engineering Deck" article will be addressing the design in depth.

[Guest]

Piston tanks have been employed in wet hull designs for decades here in the UK.





They can be heavy depending on the method of construction used, but ultimately the only thing that adds weight over other forms of ballast systems is the threaded shaft for the jack screw. A CAD image of the R & R system posted below shows the piston tank is elegantly built into the end cap of the WTC, with resin helical gears, which are quiet and light in weight. The motors are fairly large, but that enable the tanks to be swiftly retracted, dive times are under 10 seconds with these modules, so you can get pretty scale looking dive times even with WWII boats.



Engel tanks are particularly heavy I think. They are a bit over engineered, with pretty thick cylinders, metal gears, big motors etc. and it all tends to ratchet up.