RCABS seals

[eyraola]

I am currently working on the Revell U-boot type VII model that uses RCABS as diving system.
I´ve been working with seals provided by Caswell for motor shafts penetrations and found that they are adequate to keep the vacuum inside the WTC when the V-cup joint is replaced by an O-ring type joint.

It has to be taken into account that even with the submarine in surface the WTC is nearly underwater and that helps to keep the vacuum for a very long time. After some tests with both type of seals I found that O-rings keep the WTC water tight when under vacuum and sumerged , but V-cup seals are not water tight under the same conditions.

Eduardo

[Kazzer]

Do you have any photos or diagrams of your setup? It would be interesting to see how you organised things. How did you do the rudder?

[eyraola]

I am currently working on the rudder linkages . I will post some pictures shortly.

[toppack]

After some tests with both type of seals I found that O-rings keep the WTC water tight when under vacuum and sumerged , but V-cup seals are not water tight under the same conditions.

Eduardo
Very curious, it seems that the V-cup type would make a better seal, when there's higher external water pressure??? Could it be that the V-cup seals were put in backwards or damaged some way?
One advantage of O-ring seals is that they seal equally in both directions, but the V-cup type will also if you use the 2-way type or install 2 of the single type back-to-back, which makes a better seal.

[Slats]

Educate me guys what is a V cup seal?


John

[toppack]

Here ya Go, Mate:
http://www.mnrubber.com/News/One_Piece_V-Cup_Seal_Replaces_Two_Part_Assembly_Reducing_Part_ Cost.html

[Slats]

Thanks yes I have used these before (about 5 yrs back) not these specific ones but similar.

[eyraola]

I accept that I initially installed the joints without checking the position of the V-cup joints, and then I found that they were leaking when the WTC was underwater. Then I replaced the V-cup by O-rings and it worked.

With the room available inside the brass seals I am not sure if I can install double side V-cups .

[Ironhorse]

Hello there: In fact I used two of those v shaped neoprene things in the propeller shaft of my Trumpeter Seawolf.One each end,ie the regular one into the brass seal and the other one just opposite into the poliuretane cap.Result: =0 leaks

[Nuke Power]

Yes you should not be experiencing a leak with those cup seals. They seal better as the difference in pressure increases. They were either installed improper or perhaps has a tear in them or were not seated properly.. just my 2 cents. toppack actually got this one right :)

[Slats]

I am experimenting with a RCABS cylinder right now, utilising a separate air space from the main engineering section of the WTC.

J

[Ironhorse]

Hi Slats:
In my short experience I have learned that the amount of air needed to achieve a marked positive bouyancy is quite small.Also the size of the bladder is of prime consideration.Anyway is better to suck air from the part of the WTC were the pump,batteries and receiver are located and not from were the prop and pushrod seals are.

Best regards from Spain

[Kazzer]

Hi Slats:
Anyway is better to suck air from the part of the WTC were the pump,batteries and receiver are located and not from were the prop and pushrod seals are.

Best regards from Spain

Aren't the two areas connected with a tube to house the wiring?

[Ironhorse]

Hi Kazzer: You are dead right and is a very good practice (I think) to seal the hole in the cap were the wires exit with RTV.The goal is not to stress the neoprene seals with the vacuum.


As I told before my experience is limited in the area of RC subs but anyway is better to use common sense and caution and learn from experience and read the excellent contributions of the members of this forum.

This branch of RC is wonderful!!!!

[Slats]

Aren't the two areas connected with a tube to house the wiring?

Not on my setup.
All electrical connections penetrate the sealed air supply using brass rods going through the endcaps. These feed the clippard valve and the pump inside. There is no vacuum therefore on any WTC section containing moving parts. The only seals are the end caps to this section.

John

[sunworksco]

Can someone please post images of how they are installed on the bulkheads?