RCABS Compressor chamber...

[Stephen Vick]

Hi Y'all,

RCABS was very successful in my S-33 so I am doing it in my new Type VII, but with a slight change.
It is apparent to all who use this ballast system that the Achilles heel is sealing the WTC with a partial vacume. S-33 still leaks a bit, but I can live with it.
On the Type VIIc I have incorperated a 6 inch long chamber in my 3.5 inch OD WTC which is sealed off from the other dry spaces. I will locate the compressor and relief solenoid in this space. It should have sufficient volume to inflate the bladder and I will not pull a vacume on any moving seals. I am curious if anyone else has tried this approach. If not I will give a full report on the success(or failure) of this experiment in a month or two when the boat is complete.

Steve

[bigdave]

Hi Steve,
That is how I

Hi Steve,
That is how I do it in my 1/144 Seawolf WTC. There is a separate vacuum space. The rear compartment which has the output seals for the control surfaces and prop shaft does not get any vacuum. Only the center and front sections do. It works great! I have been running it all summer with no leaks or problems. BD.

[Stephen Vick]

Hi Dave,

Good to know,

Hi Dave,

Good to know, sealing the S-33 was a cast iron B, I pulled it off but I was tearing my hair out for awhile. I am determined not to repeat that pain in the Type VII.

Steve

[anonymous]

Hey Steve,

I concur with Dave.

Hey Steve,

I concur with Dave. I have his Seawolf WTC. In fact you saw it when you came up here. Never a drop.

Steve

[chuck chesney]

Did the same thing with

Did the same thing with the WTC on my George Washington class boat. The simple addition of a bulkhead made the RCABS system foolproof, and the electronics spaces bone dry.

[subsurface]

Hi gentlemen,

I am very interested

Hi gentlemen,

I am very interested in this discussion as I have just ordered and am waiting to recieve Dave's WTC for my Type VII.

I wouldn't mind some further details and/or pictures of any required mods concerning this vacuum problem.

Stan

[Stephen Vick]

Update # 1

Just had the

Update # 1

Just had the boat in the water, WTC is complete but without the RCABS. I have her trimed for dynamic diving until next payday. I have the chamber in place and pressure tested with no leaks, a 7 inch section forward of the chamber will hold the bladder and is completely free flooding. submerged performance is good with great depth control and a fair turning radius. another 2 weeks and she will have a fully functional ballast system in place.

Steve

[bigdave]

Hi Stan,
Using o-ring seals

Hi Stan,
Using o-ring seals on the outputs as the instructions will tell you fixes the problem. Dave.

[adriaticsea]

Hi all,

after looking for a

[color=#000000]Hi all,

after looking for a while at this thread and the one about making RC the Trumpeter Seawolf using Dave Welch's WTC by Steve Neill, I began to think that maybe the three-piece WTC could be just the right thing for my 1/96 Permit. Well, I've been playing with sketches and plans of a single-piece WTC for the last two weeks, and found that this way the WTC will be too long and the bladder will end too forward in the sub.
Now, I have a couple of questions regarding Dave's Seawolf WTC]

[bigdave]

Here is a photo of

Here is a photo of the Seawolf WTC. The wires that go through the rear section foward endcap are sealed with RTV. So the vacuum is only in the front two sections. The bladder is about 9"x 5", and the center Lexan tube is 1.75" OD. The other tubes are 2.75" OD. I hope this helps. Dave.



Edited By Bigdave on 1128979592

[tabledancer]

Dave,
I found the leak,it was

Dave,
I found the leak,it was a tiny gap in small end cap right where the SubTech seal is seated,it looked like the seal was leaking like I described.I did find another sealer instead of the STP like you said,it`s called"PLUMBERS SILICONE GREASE"made by" GUNK".My son who is a air conditioning guy suggested it.It is safe for anything that we will be using and not as sloppy as STP but stickier. Thanks again.
TD

[bigdave]

That's great Mike. I am

That's great Mike. I am glad I could help. Dave.

[adriaticsea]

Hi Dave,

thanks for the picture,

Hi Dave,

thanks for the picture, it's very useful together with the dimensions.
Now I just have to ask it...WHAT is RTV? I know that it means "Room temperature Vulcanization" but don't know if it's different from the standard black automotive silicone. I noticed RTV silicone on RS Components, but I don't know why sub modellers do use it instead of normal silicone.
Thanks in advance,
BEST REGARDS MAURO

[Guest]

I'm somewhat perplexed that the

I'm somewhat perplexed that the Subtech seals should cause a problem when a vacuum is pulled in the chamber. I'd have thought the seals would pull in tighter with the vacuum and form a better seal.

Andy

[bigdave]

Mauro,
RTV is silicone sealent. I

Mauro,
RTV is silicone sealent. I normally use one that is made of 100% silicone and used for aquariums. Marine Goop works good for sealing the wires as well but is harder to get off if you ever have to.
Andy,
So did I! It's a mystery! Dave.