RCABS - How do they work?

[himszy]

Hi

How does a RCABS system work?

Thanks Michael

[boss subfixer]

Michael,
Go to this web site

Michael,
Go to this web site http://groups.msn.com/artbrodersmodels you should find the information your looking for. Dr Broder is the founding father of RCABS. You may have to join his group (it's free) to access some of the areas of his site but it is worth it. It's a very slick system I don't think you'll be disappointed. I plan on using it myself but have yet to get anything up and running. Best of luck and welcome to the group.
BSF

[anonymous]

Sorry put the link doesn't

Sorry put the link doesn't work. Could you check and make sure it's correct?

Thanks,

Steve



Edited By U812 on 1104906733

[boss subfixer]

Sorry about that. I'm at

Sorry about that. I'm at work right now, when I get home I'll get the address and repost.
BSF

[Guest]

On the above link, put

On the above link, put an s on the end of the word group, and it should work. Or else, just Google 'Art Broder's Models'.
RCABS is the "Recirculating Compressed Air Ballast System", a simple system that takes air out of the WTC and blows up a rubber bladder in the wet hull area. That lightens the model to allow it to surface. When you want to dive, you release the air from the bladder back into the WTC, and allow water back into the wet hull. Repeat as much or as little as you want, as many times as you want. The same air recirculates back and forth from the bladder to the WTC.
Hope this helps.

[tmsmalley]

...or just click the little

...or just click the little globe at the bottom of Art's post above.

Here is a write up about how Dave Welch utilizes the Broder RCABS System

[JWLaRue]

....I fixed the llink......

....I fixed the llink......

[eckloss]

One question though...I would think

One question though...I would think that the vaccuum created in the WTC would increase the chances of leaks around the shaft and BHS seals. As the outside water pressure increases with depth water would naturally (try) to seep its way into the negatively pressurized WTC. Has anyone experienced any issues with this, or are there any special precautions that need to be taken? I think I've definately decided to use the RCABS system in any new boats I build...its simplicity and low cost are just too attractive =)

[bigdave]

Dr Art says he has

Dr Art says he has never had a problem with leaking, but I did. I think it is because his WTC's are larger in volume than mine and are not pulling down to as much vacuum. What I recomend in my kits is to replace the one way seals in the seal assemblies with standard o-ring seals. Once I did that the problem went away. There is more drag on the o-ring type seals but it does not seem to leak. I just keep them well lubed and replace them if needed. It really is a great ballast system, and Art was a big help to me when I started using it. Dave.

[boss subfixer]

Jeff,
Thanks for fixing the link.

Jeff,
Thanks for fixing the link.

[JWLaRue]

Dave,

Instead of replacing the standard

Dave,

Instead of replacing the standard cup seals with o-rings, I use double-seal o-rings....what I tend to think of as "x-rings" due to the shape of their cross-section. These behave like a pair of cup seals mounted back-to-back, which yields a good seal no matter which side has the higher pressure....but unlike standard o-rings, I do not get the higher friction due to binding.

-Jeff

[bigdave]

Hi Jeff,
I tried the

Hi Jeff,
I tried the X-seals and they sealed great. Unfortunately the friction was way to much for the smaller motors and servos I use in my small WTC's. The motors I use in the Type V11 would handle it but the current doubled. Plus the motors got quite warm. The one in the Kilo would not even spin. Now thats a seal!

[JWLaRue]

Hi Dave,

...maybe x-rings made from

Hi Dave,

...maybe x-rings made from a softer material? Any idea what yours were made from? Buna-n?

-Jeff

[Guest]

Hello,
John Darnell used a

Hello,
John Darnell used a similar system in his kits in the early 1980's. He used a steam engine driven by a motor to take air out of a bag and store it in either the pressure hull or a purpose built chamber. I remember it had two basic problems. At depth there was sometimes not enough air pressure to re-inflate the bag vs outside water pressure and his steam engine acting as a compressor sucked the batteries dry in less than 1/2 an hour. It looks like this system is a vast improvement. Does it suffer from depth/pressure problems? or are these new little pumps quite powerful?

[Guest]

Derek,
The newer 6 volt pumps

Derek,
The newer 6 volt pumps are quite powerful. They max out at 500-700mmHg, or about 11-13psi. They pump up the bladder easily at 10 ft. depths (and probably a lot deeper), to bring my 60" L.A. to the surface with no problem, and minimal battery drain. They draw around 450ma. Hope this gives you and others some confidence in the RCABS.