Victor III

[trout]

Bart,
It is great to see you moving forward.
The failed print was probably because there was not a drain hole in the bow. As the layers are getting layer down, the catching of a bunch of resin was too great for the first few layers.
Peace,
Tom

[bwi 971]

Bart,
It is great to see you moving forward.
The failed print was probably because there was not a drain hole in the bow. As the layers are getting layer down, the catching of a bunch of resin was too great for the first few layers.
Peace,
Tom

Did not think about that route, thks for pointing that out Tom.
All the best
Bart

[bwi 971]

It's been a while due to various reasons and other scale projects.

All parts were printed with better supports this time.

My intention was to use a transversal cut to gain access to the internal WTC. However, that did not work out, so I had to split the hull longitudinally. I wanted to provide index pins before the split because it was difficult with my Akula to match the seam of the upper and lower hull parts.

I have 6 hull sections, 4 of which will be split.

For each hull part, I prepared 4 index pins. The radius of the index pins differs depending on the position they will be glued into the sections. Distance blocks were also prepared with various heights and will be used to support the indexing pins when glued in place.



I temporarily assembled the six hull parts together with tape, ensuring the assembly was plumb both transversally and longitudinally, and traced the separation line all around. This line was transferred to the inside so I could align the index pins to it.










Next, I glued the index pins to the hull sections using the distance blocks.





The next step was gluing all the hull sections together and making the longitudinal cut. I used a thin Japanese saw, with a kerf of only 0.5mm.









Grtz,
Bart

[trout]

Bart,
Great to see you are still at it! I have missed your postings.
Peace,
Tom

[Marylandradiosailor]

What material was used for the numbered blocks? (the ones that will hold the pins) Thx.

[bwi 971]

What material was used for the numbered blocks? (the ones that will hold the pins) Thx.

PETG, glued in with epoxy, 4mm holes were included in the print and afterwards reamed for a snug fit.

Grtz,
Bart

[bwi 971]

Bart,
Great to see you are still at it! I have missed your postings.
Peace,
Tom

Thks Tom, It has been too long, feels good to work on somthing for myself.
Grtz,
bart

[bwi 971]

Made all the 4mm stainless steel (SS) indexing pins (tapered), reinforced the hull with frames that also serve as supports for the WTC. Very happy with the result, very tight fit of the upper and lower hull without any additional tweaking.











I used also indexing pins for the stern appendages.









Designed also the yokes, the rudders will have an 60° rotation each side and the dive plans 50°.



Grtz,
Bart

[SSBN659]

Like Tom, I too am happy to see you're back at work on the Victor III. The one I made years ago was a lot of fun but it was nowhere near what you are doing. Way to go Bart!

Will Rogers
SSBN659

[bwi 971]

Bow and stern glued in place with CA. As I don't want to rely solely on the CA, I added a strip of fiberglass mat on the section seams and fixed it with epoxy.







Grtz,
Bart

[Tom Spettel]

Wow this is great work!

[bwi 971]

I've been occupied with the design of the WTC.

To determine the minimum lifting capacity of the WTC, I measured the weight of the hull above the waterline when surfaced. As with my AKULA, I used Archimedes' principle, calculating the difference in weight between when the vessel is surfaced and when it's submerged. I determined that a minimum of 310 grams is required.
Measuring setup.



After several prototyping runs, I realized I had a massive oversight regarding the pumps.

I ordered a water pump and, upon testing it, discovered it was a one-way pump, not reversible. I decided to use two pumps instead and adjusted the design accordingly. The pumps would rest in cradles, and "sea" suction and overboard functions were integrated into the intermediate cap, which acted as the bulkhead for the ballast tank. I was quite proud of the design until I realized that the pumps were "open," meaning they allowed water to flow freely without running. This oversight felt rather foolish and embarrassing, to be honest.

I abandoned the idea of using two pumps and sought a reversible gear pump. In the past, cars on this side of the pond used windshield washer pumps from the brand VDO, which were gear pumps. I know that a gear pump also backflows when there's a pressure difference, but I pondered providing a loop above the water surface level to mitigate this.

I couldn't find a suitable mini gear pump, and the VDO pumps are hard to come by. Furthermore, I wanted a brushless motor to drive the pump. So, I decided to design one myself. I'm not sure how well it will work, but it was a fun challenge. I'll use 4mm shafts, as I use them wherever possible. I buy 3m lengths of this material, and I have seals and bushings in my standard stock for the 4mm shafts.

For the seal between the cover and the housing, I used an O-ring. O-rings can be used in rectangular or non-circular groove patterns, but it's important to consider the minimal bending radius, which should be at least 6 times the circumference of the O-ring. I calculated the required ID of the O-ring by converting the circumference of the rectangle to a diameter. The inlet and outlet are part of the cover and will face towards the intermediate cap of the ballast tank (which I will redesign).





The prototype needs to settle for a few days to allow shrinkage to occur. The clearances and gear backlash seem okay at first glance, but further settling is necessary. Any design flaws or weak spots will be revealed after conducting a test run.





Below is a rendering of the WTC designed for two pumps.
Servo rack (Yellow)
Pump Saddles (red), now obsolete
Ballast tk, inside I provided a fairly large conduit for the cables (silver)





Several prototypes have been made and adapted to overcome issues.

Servo rack



Encap


Pup racks (now obsolete)







Grtz,
Bart

[Albacore 569]

Wow! Thats so interesting. Using the Archimedes' principle, how does the 310 grams weight you registered translate into ballast tank volume according to your calculations?

[bwi 971]

Wow! Thats so interesting. Using the Archimedes' principle, how does the 310 grams weight you registered translate into ballast tank volume according to your calculations?

the 310gr or 310ml is the minimum ballast tk volume required.

[bwi 971]

Assembling the pump. Tolerances were still good after fully curing.

Lip seal and bushing were pressed in place using the drill press.





The bushing and gears had an overlength to allow machining to the correct length. For the gears, I used a brass tube with the correct ID to hold the gear so I could secure it in the chuck of the lathe.





Both pump housing and cover are secured together using stainless steel M3 bolts.






Waiting for the arrival of the O-rings for a test run.

Grtz,
Bart