German Type 212A 3D Print Build

[biggsgolf]

Rob, are you printing this at 1:72 scale approximately 31"? What is the distance from the forward bulkhead cap to the edge of the nose opening? Hope this makes sense! I may build it with Subdriver that has a ballast tank. Need to determine scale I would need for it to fit.

[rwtdiver]

Hi Steven,

Thank you very much for taking the time to list out what you have done for your Dolphin stern section. I have fabricated a similar type brass yoke for most of my standard + tail designed boats.

Your right the inside area to try and work with on my 212 is an issue for me. The system that Bob is using on his 212 A kits is the one I have fabricated, but the 1/16" brass rods have way to much flex and are not working for my 3D printed 212. I took "SUB Eds" advice and ordered up some of the 1/16" S.S. welding rod, and I will give that a try. I am sure it will have less flex and be a more stable system. I also have a couple more ideas to help compensate for the tight quarters.

Thank you again Steven! Your help and ideas are GREATLY appreciated! :-)) As we do in this hobby! Keep working till we get it!

Rob
"Firemen can stand the heat."

[Albacore 569]

Steven,

Our two boats (Dolphin & 212 A) are very similar, especially with the X tail stern.



I am very impressed with the brass linkage system that you built. Really excellent work Steven! If it is OK with you, I may try and duplicate what you have done here for my 212!? It is a really clean and effective.looking system.

I can see where your cylinder hold downs would be different because of your PVC hull section.

Rob
"Firemen can stand the heat."

Sure, you can make a duplicate of your own. I am flattered, but I did post here so others could learn from me (or my mistakes...lol) . I am just following others designs too after all. Importantly I would change the overall size and sizes of the same parts to fit into your smaller 212A or there will be clearances issues in a area cramped already.

The first thing in your model is determine (as what I followed first) what is the largest reasonable diameter solid brass rod for the rudder posts possible that slides into the rudders. Smaller will fit but largest you can use will be the more robust. That will determine the Dubro locking collars sizes (the diameters).

If you run out of brass solid rod stock, buy more or if have to wait again ordering online delivery, if you have similar sized brass hollow tubing, then slide in concentric tubes inside the larger and solder together. Just as strong, hell same principle worked well for the Supermarine Spitfire's wing spars.

It took me several tries of making the components to get the soldering down after practice. I used a normal soldering flux, and then silver solder and a small hand torch and a vice, with aluminum tubing acting as fixtures to maintain alignment (critical). I then used rubber wheels in a hand piece to clean up the parts after soldered and smooth out the silver solder. 'Merriman and Martin' have illustrations and you tube videos in various places to help guide you.

Years ago, a suitable anti flux while soldering (creating a barrier where you don't want the solder to flow) could be used with Pencil lead (graphite). Scribble over the area with a pencil. But I noticed that didn't work this time, so I think the pencils graphite must have changed or I have...lol.

Du-Bro nickel plated shaft wheel collars sizes. In my Dolphin 2, I used 1/8". That was the maximum diameter possible in my case on the Dolphin 2. For your 212A, you have to step size down, so they fit the appropriate size rudder posts.

• 1/16" (1.5 mm)
• 3/23" (2.3 mm)
• 1/8" (3 mm)
• 5/32" (4 mm)
• 3/16" (4.7 mm)
• 7/32" (5.5 mm)
• 1/4" (6.3 mm)

Ideally, since you have a 3 d printer, could you follow the public source design and just design and print your own out of suitable strength material? Doesn't Bob provide a suitable linkage for his 212 kits? I see in his videos Bob seems to crank out plenty of his beautiful 212A's for clients too. Just some thoughts.

My eyes aren't the best either. I just went to the optometrist and getting new up close and far distance glasses. I've been diabetic type 1 for 50 years as of March 19th, 2024. A personal milestone for me that I made up in my mind t keep me going. My eyes seem to have the effects of diabetes over time, but fortunately seem well enough to not need injections or lasers. I hope I pass the DMV drivers test soon. The new Rx glasses should be a huge assist. I got to be able to drive to the ponds to be with you guys' 'Simmerly afflicted' lol. Not afflicted with diabetes, though I have run into a lot in our local group a number of f diabetics' the same age and time but afflicted with model submarines...lol.

[rwtdiver]

I have the linkages all tied in (I THINK)



Not my most favorite way to link up the stern control surfaces. I may have to go back to the old traditional methods. We will give it a try and see what happens!

Rob
"Firemen can stand the heat."

[rwtdiver]

After looking at the different types of stern linkage systems, I have decided to go with the one that Bob Martin uses on his 212 A Kits.





With the stern section being open as it is it should be relatively simple to put together. I soldered up the brass horns about 3 weeks ago, so I might as well use them.

Rob
"Firemen can stand the heat."

[rwtdiver]

Before I start on the stern linkages!





I sprayed the interior of the stern with a primer/paint coating. I did not want to spray paint after the linkages have been installed.

Rob
"Firemen can stand the heat."

[rwtdiver]

As you , comparing your 212 build with my Dolphin 2 build.

Interesting design, that works well for the hull halves.

In my Dolphin 2, Bob Martin took a different tact for making my WTC supports. Because my WTC will be inside a free flooding PVC pipe, the supports for the WTC are in the ends as rings. I'm sure both ways will be effective. The future batteries will be in heat shrink tubing waterproofed between the WTC and the hull bottom.

The clearance isn't enough for the batteries with the PVC pipe alone, but a midships longitudinal large slot will be cut and the line of batteries laid into the PVC pipe slot out the bottom. The long bottom fairing extending down will then provide plenty of room and make the hull even more free flooding while and still scale.

The bottom fairing will be removeable too providing easy battery access. as well as lowering the boats center of gravity metacenter making her a more 'stiff roller'. Thats the idea will see. That stage in building approaching quickly.

Steven,

Our two boats (Dolphin & 212 A) are very similar, especially with the X tail stern.



I am very impressed with the brass linkage system that you built. Really excellent work Steven! If it is OK with you, I may try and duplicate what you have done here for my 212!? It is a really clean and effective.looking system.

I can see where your cylinder hold downs would be different because of your PVC hull section.

Rob
"Firemen can stand the heat."

[Albacore 569]

As you , comparing your 212 build with my Dolphin 2 build.

Interesting design, that works well for the hull halves.

In my Dolphin 2, Bob Martin took a different tact for making my WTC supports. Because my WTC will be inside a free flooding PVC pipe, the supports for the WTC are in the ends as rings. I'm sure both ways will be effective. The future batteries will be in heat shrink tubing waterproofed between the WTC and the hull bottom.

The clearance isn't enough for the batteries with the PVC pipe alone, but a midships longitudinal large slot will be cut and the line of batteries laid into the PVC pipe slot out the bottom. The long bottom fairing extending down will then provide plenty of room and make the hull even more free flooding while and still scale.

The bottom fairing will be removeable too providing easy battery access. as well as lowering the boats center of gravity metacenter making her a more 'stiff roller'. Thats the idea will see. That stage in building approaching quickly.

[rwtdiver]

Today I managed to make a little more headway on the hull.



I glued up the bow section using the PLA pins and CA. I also used the soldering iron to melt the bow section to the hull. Which by the way was another good suggestion from Bob Martin. This idea has certainly strengthened all the sections on the hull.



I also 3D printed the cylinder saddles and glued them in as well.



I also sized and cut the Velcro straps that will be glued inside the saddles to secure the cylinder to the saddle itself.

Next will come the installation of the control linkage system to the inside of the stern, and then glue the stern section to the hull.

Rob
"Firemen can stand the heat."

[biggsgolf]

There will be a forward and aft supports for the end caps to slide into.

Rob
"Firemen can stand the heat."

Sounds good!

[rwtdiver]

How will you ensure Cylinder does not move forward?

There will be a forward and aft supports for the end caps to slide into.

Rob
"Firemen can stand the heat."

[biggsgolf]

How will you ensure Cylinder does not move forward?

[rwtdiver]

Today I spent my time designing the hull cylinder holders for the 300 series EasyDriver.



After I did some paper drawing for the sizing, I went to Tinker Cad and set up the design for STL printing.





I am most likely going to use 4 of the holders. So I set up my Dremel to print out 2 at a time.



The Velcro will not only give some padding, but will also be used as the cylinder hold downs.



The holders turned out very good and fit nicely around the cylinder.

Rob
"Firemen can stand the heat."

[rwtdiver]

Here is another tool that will help fill in gaps and make more positive joints in PLA.



It is a PLA Melting pen. It's great for filling gaps..

Rob
"Firemen can stand the heat."

[rwtdiver]

Great thinking, Rob. You could also use a soldering iron to fuse the nubs to the hull itself, almost like a permanent rivet.

Bob,

You read my mind! (that's scary)



I am in the process of taking one of my old soldering irons, and fabricate a brass rod with a slightly flat chisel tip. This will accomplish exactly what you are suggesting.

Rob
"Firemen can stand the heat."