Hybrid Ballast Tank/Piston System

[Monahan Steam Models]

As mentioned earlier progress has been made on the aft upper equipment shelf. Here's the update.





Upper shelf designed and made. It's attached to the bottom shelf with the dual LiPo's in between. Receiver and Arduino nano in place with ex pander unit mounted above. Also got the aft bulkhead designed with the dual brush-less motor connections and the central servo connection connection figured out.



Dual LiPo connections, port and starboard, made as well as the dual motor connections. Note the slip in equipment shelf tab interface with the rear end cap to keep things level and in place
.
Overall view.



Starting to wire the components. 5V ground and positive bus installed on the port side,



Aft ESC hook-ups to the aft bulkhead.



View of rear bulkhead and brushless motor connections.



Outer end view of aft WTC cylinder bulkhead.



Rainbow signal cable harness connection from forward component unit to aft command center.



Forward main 11.4V, 5V and Ground connection added to rear lower power distribution shelf.



Overall current view of the nightmare i created for myself



Forward signal connection.



Aft signal connection to come.

Now that most of the main systems have been built and linked together with their respective hardware focus has bee been shifted to how to control this hot mess through code and direct communication. This is were the possibilities are endless Pick your flavor. What do you want automated and what do you want directly controlled, and just to mess you up further, what do you want a mix of?

[gantu]

Thank you tom here the link i forgot.

https://de.aliexpress.com/wholesale?catId=0&initiative_id=SB_20210316002216&SearchText=terminalblock

[trout]

Gantu,
You, sir, are a fountain of knowledge or resources relating to our hobby! Thank you for that terminal block!
Peace,
tom

[Monahan Steam Models]

Gantu,

Thank you and great find with those terminal blocks. Thanks for sharing these.

Regards,

Nick

[gantu]

Very nice job with your 3D part and pcb board. I will give this an try.

[Monahan Steam Models]

Nick,

That is the neatest, most efficient packaging of devices I've ever seen. You've taken me back to school, pal. Those capture type bus-bars save a whole lot of soldering. Most innovative.

David

Thanks Bud!

[Monahan Steam Models]

Stealing these ideas! LOL Really excellent organization.

Steal all you want buddy! That’ is exactly why I share these builds! If something I post helps the hobby or someone’s project then it’s all worth it! Heck, the reason I have gotten this far is from all the hard work that was done by the many I learned from that came before me and the ones I’m still learning from today!

[trout]

Stealing these ideas! LOL Really excellent organization.

[He Who Shall Not Be Named]

Nick,

That is the neatest, most efficient packaging of devices I've ever seen. You've taken me back to school, pal. Those capture type bus-bars save a whole lot of soldering. Most innovative.

David

[Monahan Steam Models]

Some more progress has been made since the last project update.

Arrived at a final design for the aft compartment lower equipment shelf/battery tray after many, many hours of trying to find the optimal layout for all the electronic components. Here is what I've come up with so far.



Bottom side of lower equipment shelf. From top to bottom in the photo: Top is the remote on/off switch that turns on or off the mosfet heavy duty switch board in the middle. The mosfet switch turns on or off the power much more smoothly than the coil relay and can handle more current. The lower component is 5V 6A voltage regulator.


Top side of the lower shelf where the two LiPo batteries will sit.


Starting to create the 12V bus bar using 5mm screw terminals. I use circuit prototyping boards as backbone or support for the screw terminals. I rip these circuit boards down to what ever size I need using a mini precision table saw. This terminal bus bar has ten positions. The four pins on the right side will be constantly 12V hot or charged when the batteries are plugged in. The remaining 6 positions will be switched 12V hot fed from the mosfet switch. 16AWG wire is used to bus the pins together. On the prototyping boards you can break the circuit by cutting the thin metal circuit material bonded to the board with a blade or a file as shown above.


16AWG stranded wire soldered across the pins to creat the 12v positive bus bars.


How it fits in the bar holder. The slot in the holder shows how the circuit board is secured.


Another photo of the bus bar holder.


10 position ground bus bar finished.


Finished bus bars mocked up in lower shelf.


Topside view.


Additional bus bars. One is a ground. The other is 5V positive.


Starting to fit the 5V regulator and the 12V mosfet switch. Forward 3 position bus bars installed.


Wiring! Although the 5V regulator use two 2mm screws to secure it to the equipment shelf, the bus bar holders were designed to slightly overlap the edges of the circuit boards to hold them in place in their countersunk wells. The Battery and Link Monitor is about to be secured in place with the double sided tape attached to the tabs on the bus bas holders.


Getting there! in the top of this photo you can see the 3 position ground bar is connected as well as the 5V bus bar.


Another view of the top side with the components installed.


Front side view.










Dual ESC's now installed along with the finalized main power wiring. I wanted to add poly-type fuses to each of the ESC in case of a over amp situation like the propellers snagging weeds or such. This would've allowed the ESC's fuse to blow at a lower amp rating without blowing the main fuse. As you can see I already have 10 pounds in a 5 pound bag, so no room. Instead I will use magnets as slip clutches for each prop shaft.

Work has also began on the aft upper equipment shelf. I will post an update about that shortly.

Nick

[Bob Gato]

I have a link to a company who supplies clear tubes made from PET.

PET is a very stable food grade plastic that is also used to ship various chemicals and products in. It is -It's impervious to Freon, MEK, Acetone Trichlorethane, Toluene, and my Chili Recipe!
in fact most of those chemicals were dispensed for use in the Grumman tool crib in PET containers.(except for my chili)... Their tubes range in all sizes including 3' OD with a .125 wall thickness-the minimum buy makes it a little pricey but if purchased with others, it would be doable.

Nick, I know that a little cosmetic crazing aren't going to stop you but for future builds and other readers I wanted to post the link but the guardians of the trolling bots won't authorize it. I'll PM it to you (and anyone else who wants-just PM me a request.)

As for the crazed welds that don't leak -that would be a good spot to position stainless hold down straps...

In the meantime I'll try to find that supplier of 1/8" wall PVC in 3" tubes-Its out there -I saw it!

[Subculture]

AFAIK, the OTW cylinders use extruded tubing. The earlier Craycraft modules made by Brian Cornelius, which were once used with OTW hulls featured extruded ICI Perspex (TM) tubing, and that will be of excellent quality. Not sure how easily available that is now, as we’re talking over twenty years ago.

Cast acrylic/PMMA tubing costs a small fortune and tends to be very thick walled 4-5mm. I expect shipping to the US will be pretty eye watering too.

Polycarbonate is much tougher, but used to be unobtanium until a few years ago here in the UK. A lot easier to source now, but it is more expensive than acrylic and much more so than PVC. With PC and PMMA you get a better choice of diameters to choose from than the latter.

I guess many builders desire the high-tech look of a transparent wtc/dive module, and it’s become synonymous with quality commercial items. I personally favour utility over looks though, especially when it sits inside the boat out of sight.

I would personally look at leaving out the glued bulkheads, although I do appreciate that will require some significant redesign.

[Monahan Steam Models]

Usually when clear tube based ballast tanks have bonded/welded ends, the tubing is cut and bulkheads and machined with a step in them , then solvent welded onto the end of the tubing with a minimum of solvent. A good example are the OTW modules. R&R modules side step the problem by using a smaller tank that has o-ring sealed caps and that slides inside the larger diameter tube for the main module.

I’m guessing the Arkmodel acrylic tube is extruded and not cast. This would explain the stresses in the material as you have pointed out earlier. This makes sense. This is also assuming on my part the material is common extruded acrylic. It smells like it when it is cut.

I considered early on making the central ballast tank a separate cylinder altogether or possibly using radial o-rings to seal the tank’s machined bulkheads. I’ve heard of and have seen photos of the OTW units but have no first hand real experience with them. Curious if they use extruded or cast tubing. They look like very nice well executed units.

For now I plan to order some cast 90mm acrylic tubing from a reputable U.K. supplier and do some tests bonding bulkheads to this material and learn if this remedies the crazing issue with the current design. If not I will explore other design options and materials suggested.

[Subculture]

Usually when clear tube based ballast tanks have bonded/welded ends, the tubing is cut and bulkheads and machined with a step in them , then solvent welded onto the end of the tubing with a minimum of solvent. A good example are the OTW modules. R&R modules side step the problem by using a smaller tank that has o-ring sealed caps and that slides inside the larger diameter tube for the main module.

[Monahan Steam Models]

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' PVC-"

Did some searching this morning for clear PVC pipe and tube. Lots of schedule 40 out there! Trickier to find the 1/8" wall stuff! Might be hard to find a 1/8" wall clear PVC tube close to the dimensions of this 90mm acrylic tube. The 90mm tube I'm using currently measure 3.562" in OD which is just a bit over 90mm. The boat hull was designed to accept 90mm. You could get away with a tube slightly larger than this but not much larger.

I have a six foot length of 3.5" x 1/8" extruded acrylic tube on hand but I would need to redesign and remake some of the equipment shelves to use this material. It might also craze since it is extruded and not cast. This same size material is available in cast but is almost four times the cost.

I found a supplier this morning in the UK who sells 90mm OD X 3mm wall cast acrylic tube in 2000mm (78"+) lengths for a lesser price to what I've found in the States for a 24" piece of 1/8" wall 3.5"OD or 3.625" OD cast tube.




Although the crazing on the central ballast tank looks dreadful, I was surprised to find that the tank was water tight after some tests this morning! I first filled the tank up completely and let it sit for an hour. No leaks. Then with it still full I added some pressure. Still no leaks!

At least for now I can keep moving progress forward, eventually towards testing with the tank like this. I'll replace it when I can get my hands on a suitable replacement material in a similar size.