Robbe Type 7 8-ball project

[bigdave]

As of today the cylinder has been handed off to Greg.
He will be continuing the build from here. BD

[greg w]

here are some pictures of what I have . There is also alot of collars and bits and pieces not shown. Thanks again to Jim Smith. I also want to thank Jeff LaRue for donating the missing deck section. It will only cost some SC articles.Also there are a few pictures of the tech rack that BD made. He does awesome work. You just need to know how to butter him up.cookies, chex mix and being a persistant PITA works well. More to come when there is something to show. Greg W aka Mr PITA

[crueby]

Looking great guys! That is going to be a big ... umm... diver!

[jim smith]

I'm glad to see her coming back to life. I so happy to see someone or ones actually do what the say. I had another one that I gave to someone who seemed excited to build the sub only to turn around and sell it and not think anything was wrong with that. Great job guys.

Jim

[JWLaRue]

It will only cost some SC articles.

-Jeff

[Foxtrot Oscar]

Just seen this, i like the design, however i would suggest that you have some form of relief valve from the high pressure side of the pump , back outside the hull or back to low pressure side of the pump (so it recirculates). Gear pumps can create massive pressure if locked in. i realise you have the limit switch when the bladder is full and also the electric valves for dumping, but there's always the what if the pump stays on scenario, and these features don't work.

[bigdave]

That is a great idea and deserves an answer.
Short answer for me it's beyond my abilities, and feel the effort to try and make or obtain a relief valve is not worth the gain in piece of mind. The limit switch should and does do the job nicely. Remember this is a model and does not need a redundant system. If I was building it to ride in it this would be different.
I also chose a pump that was not too powerful and will stall out before the pressure got to dangerous.
We (Greg and I) also run our ballast on a center off spring loaded switch on the transmitter.
This eliminates forgetting to turn it off. (Done that)
And if the bladder should rupture the water is contained in the cylinder it is in.
But I do thank you for pointing it out and hope you understand my reasoning.
Misguided as it sometimes is. BD

[Foxtrot Oscar]

I'm sure it's not beyond your abilities 😀, but understand your confidence levels in the current set up. I'm looking at something similar myself as I've got most of the parts lieing around. I'm thinking about modifying a tire valve to act as pressure relief, just in case.

[greg w]

Well here is an update. My motivation is starting up again. I am sure BD would want me to continue as he felt the cylinder was some of his best work. I have attached the bow section to the center as well as putting on the bow plane supports.
I also fabricated a stern bulkhead out of some 1/2" pvc that I glued to the stern section and then to the rear of the rack. The wtc tube is not glued into the center section yet. I want to wait until after initial ballasting is done so that I can put any extra lead in the very bottom of the hull. Next will be fitting out the stuffing boxes and the rear control supports. I am also looking for any layout info on the conning tower floor. The Robbe tower has no detail to it there and I have seen pictures of photo etch but it isn't availble anymore. Does anyone have a layout pattern for a type VIIB and what size the holes should be. I realize this model is not perfect but I know I can make it better. Greg W

[greg w]

Nothing new to post. I have been working on the project slowly. I wanted to be able to take it to carmel but I didn't want to half a$$ it so it stayed home. I did find a site in germany which is still making some brass details for the boat
http://srs-pe-robbe.blogspot.com/ and another over there that does parts in plastic https://modellbau-wikinger.de/epages...40&PageSize=36

[greg w]

This project is still alive! I even got it into my test tank to see how much ballast to add. All systems appear to be good. I should have this out at Carmel this year. It probably won't be 100% done but I'm not sure any really are except shelf queens

[JWLaRue]

Greg,

Good to hear that it's almost completed.

....don't forget that SCR article.

-Jeff