Hybrid Ballast Tank/Piston System

[Bob Gato]

Crap is right-I feel your pain man! If you search hard on the net, there is a such thing as clear PVC-but most are as thick as standard schedule 40 pipe-search more and you can find 1/8' UPVC-" (schedule 30) Also PET is a great clear contender for a subdriver.- I try to find a link (I have a link management problem)-BG

[Subculture]

That’s rotten luck. Perhaps there were some residual stresses in the tube, or it’s poor quality plastic, clear plastics can be fussy. I prefer to use pvc or polypropylene tube which tends to be filled or is at best translucent, so what! Cheap, tough as old boots and doesn’t craze.

[Monahan Steam Models]

Sometimes ya win some, sometimes ya lose some....

Machined the bulkheads for the central ballast tank. Carefully made the drain holes and the vent hole in the WTC tube. Everything fit up perfectly and turned out well.

That was until the final step of applying the welding solvent...



Things went crazy.... Literally.



The WTC tube crazed where ever the Weld-on 4 came in contact with it. The bulkheads and smaller conduit tubes did not suffer the same fate.



Any ideas what went wrong? The tube is from the original Arkmodel piston tank WTC kit.

Nick

[Monahan Steam Models]

Got the main pressure depth sensor installed and hooked up. It’s on the starboard side near the ballast pushrod penetration just forward of the starboard signal junction buss. The torpedo harness is also connected to the TCP module.

On the port side you can see the 5v positive and ground junction buss with TCP in the middle. The dual esc for the trim peristaltic pumps is just aft of the TCP module. Might dump this esc and replace it with a H-bridge unit. (Not happy with the cheap esc)




A view from the bottom side shows the completed pump wiring and the main 3 wire power connection. One ground, a 5volt positive and a 11.2 positive.




Nick

[Monahan Steam Models]

Quick update.

Parts have arrived and here is the current state of the forward compartment equipment assembly as of today. Almost finished with the initial assembly mock up of the forward compartment. Just need to add the main depth sensor, main power harness and finish the torpedo command circuits. Will try to write a more detailed report of the build when I get a chance.

[Monahan Steam Models]

Thanks Tom!!!

[trout]

Nick,
I am enjoying your progression on this. Thank you.
Peace,
Tom

[Monahan Steam Models]

Quick build update. Was out of bed, vertical and working on the first cup of coffee thanks to the indoor cats and little rug rat deciding it was party time at 3am this morning.... With one eye barely open and the other still twitching open and closed I picked up where I left off on the upper equipment shelf build.

Installed the port and starboard mounting brackets for the depth controller and the controller for the low pressure blower pumps to the underside of the upper equipment shelf.



The screws that hold these in place also hold the above linear pushrod blocks above in place. They act as stiffeners as well.



Above linear pushrod blocks. Only purpose is to lessen side forces on the bulkhead seal bearings from side force transmission from the servos. They are sleeved with a machined Delrin bushings with a few thou tolerance clearance.

Last lazy pic of the day, of what I have so far. Waiting on critical small parts to show up for the next forward compartment mock up. So not many updates to follow until those parts get here. Look like they will trickle in over the next couple weeks. Until then I’ll find other areas of design to explore.

Nick

[RCSubGuy]

This is looking awesome, Nick! Great work!

[Bob Gato]

...and it allows you to go to bed and wake up to a finished print...

[Monahan Steam Models]

Got up early this morning and pulled the freshly finished lower pump equipment shelf out of the 3D printer. A quick clean up of a few holes with various sized straight flute machine tool reamers and it was time to test fir the peristaltic pumps and hoses to it.





Even if this whole experiment proves to be a huge failure, at least it was a learning experience and I'l have a pretty neat looking failure trophy to stare at. Hahaha!




I had purchased the raw materials to make most of these parts on my mill and lathe but decided to see how printing the parts would turn out first. The finishes of the prints are rough in areas as I am experimenting with printing in lower quality (faster) print settings. I will sand these parts at a later date or give them a vapor smoothing treatment. Still getting to know this machine even though I've made lots of parts with it over the last year.

Prior to this Experimental WTC project, every part I printed was in the highest resolution and made from ABS due to many parts being small and having critical tolerances. The larger parts of the WTC would take forever if I printed them in the highest resolution. Still I know I could machine most these by hand much faster than the printer could print them at it's lowest (fastest) setting. The nice thing about the printer vs manual machining is, this allows me to focus my time in other areas.


Nick

[Monahan Steam Models]

Here is the current progress as of this moment on the WTC build experiment.



Backside of the forward end cap.



Different camera angle. The brass nipples were a press fit. All of the various holes were finish sized with a straight flute reamer prior to the test fitting the parts to the assembly.




Port side view.

Here the brass emergency gas blow valve visible as well as the brass adjustable pressure regulator for the torpedo solenoids.

The push rods used u-cup seals. I used Bob's trick to build them that he explains in detail on his YouTube channel. The only difference is i use an oil-lite bearing on either side of the u-cup seal. The bearings are held in place with a dab of blue Loctite.

The IP68 one piece molded multi pin connector passes through the end cap using a IP68 rated cable gland. Silicon sealer will be used on the threads and sealing bit of the cable gland during final assembly. Not needed but extra insurance.




Starboard side.

Both push rods travel very smoothly. Here you can see the other brass valve that vents the main ballast tank.



Underside.



Test fitting with the 90mm OD Acrylic WTC tube. Nice consistent O-ring squish all around.



Test fitting it to the hull to see how I did taking measurements and verifying what I designed in CAD land. Fits as planned. Guess I'm not fired today but there's always tomorrow.




This about catches up the work with the real parts to date. Need to wrap up a few minor details with the forward equipment shelves before I make those very soon. I had shifted focus recently in the CAD design to the rear compartment and motors but the forward compartment was so close I figure I should finish that first.


Enjoy the weekend,

Nick

[Monahan Steam Models]

Sneak peak of the project progress.

[Monahan Steam Models]

It was a surprise to hear the crickets and frogs last night. I had just gotten the kiddo off to bed and was waiting for a part to finishing printing so that I could load up another before turning in for the night. Decided to step out on the back porch and was hit with the wall of sound coming from the crickets and frogs.

Normally around this time of year it is very quiet out besides the sounds of the bigger critters roaming around. Mainly because it would be freezing out or snowing so it was odd but at the same time very soothing. A nice treat after a long day spent working on the computer.

[trout]

Well your two sentences made me day dream. There is something to those sounds that is both relaxing and inspires creative thinking. You’re living my dream.