Something to replace the Neptune - Short Typhoon?

[Ed Kirk]

I did a simple pressure test on the 3D printed ballast tank/water tight compartment by using my mouth to blow into the tank - did not hold pressure. I purchased a cheap very small air compressor on Amazon and used it to pressure test tank, covered it with soapy water and it foamed up like the head on a good beer. So I coated the tank with cheap resin, this time it holds air, also filled the battery box with resin. Edit, about $5.00 material to print tank, probably cost more to power 3D printer for 8 hour print.

Confirmation, 3D printed parts leak, printed solid at 3mm thick! Battery box printed at 2mm thick and didn't leak resin though. Leak test with air compressor never exceeded 2.5 psi.

I am impressed with the little air compressor, very small and has a battery. I can't figure out how to take it apart but for $25.00 I want to see if it can be converted to blow ballast.

[Ed Kirk]

Do NOT do infill at anything less than 100%. Water absolutely will get into the voids, causing a loss of buoyancy, and then it will also drain water for a week after you get it out again.

Yes, I know, I printed some shells for my clock projects and filled them with epoxy resin/lead shot and they leaked. Went to a two stage process - coated the inside with resin first then filled with resin after the first coat hardened.

It is FINISHED except for trimming. I made a lot of changes since I started but ended up using my original concept of a round ballast tank with dry tank inside. I decided to test system without coating with resin to see if it leaks. It was submerged in the water for a couple of hours and stayed dry.

[RCSubGuy]

The stern is just a little low, after thinking about it the parts in red are printed solid, I can slice them to 3 layers with about 20% infill and greatly reduce their weight. The water line is just below the top of the prop shrouds, the props should just be exposed.

Do NOT do infill at anything less than 100%. Water absolutely will get into the voids, causing a loss of buoyancy, and then it will also drain water for a week after you get it out again.

[Ed Kirk]

Printing new ballast tank, added two auxiliary tanks to displace water when flooded. they will be open (with a cap) on one end to allow for addition of lead ballast if needed.

[Ed Kirk]

It's in the water - kitchen sink- surface looks great, a little heavy aft. Submerged is very negative, need some foam.

OR

May print another ballast tank and leave dry internal tank for positive buoyancy. Should an internal dry tank be low in the ballast tank or at the top, It looks like about 20% displacement in the ballast tank? I think high.

Edit - The stern is just a little low, after thinking about it the parts in red are printed solid, I can slice them to 3 layers with about 20% infill and greatly reduce their weight. The water line is just below the top of the prop shrouds, the props should just be exposed.

[Ed Kirk]

I don't like the yellow - it's PLA glass filled, doesn't print well. Probably stick with white with red trim.

[Ed Kirk]

Finishing up and testing electronics tray, designed to slip into end of ballast tank. End cap and tray single print, keeps things tidy when complete. Getting close to getting wet.

Just curious - is there interest enough in this project for me to post the STL's? No cost, but since Bob owns and sells the files it would be his decision. I don't plan on selling anything and some STL's would have to be purchased from Bob anyway.

If this works out I will probably re-work the full length plans to take my modifications but use regular twin ballast tank kit since I already have one.

[Ed Kirk]

Battery box slips into cylinder using threaded rod to guide and hold in place, bow bolts on threaded rod locking in place. To remove battery, remove bow and slide out battery.

[Ed Kirk]

Printed battery box.

[Ed Kirk]

I am going with a simple battery, 12V NiMH (3000 MaH) and dedicated charger from Servo City. Both come with XT30 plugs and the battery has an inline fuse holder and fuse.

[Ed Kirk]

I printed the main tank, both inner tube, outer shell and one end cap in single print then added 5 baffles and other end cap. I don't think the printed parts are water tight and will coat the inside with casting resin which is very slow to set and drains out leaving very little excess.

[Ed Kirk]

Project moving along, I decided my modular process didn't leave enough space for components. I went back to my original plan to print a tubular design, the center tube is dry for electronics and battery. I plan on using epoxy to seal the tank from the inside. Filled ballast section - 36 oz. water.

My SubSafe inspectors at work.

I am working the project from the outside - in and acquiring needed components as I go so process is slow. Just got battery and FrySky receiver, able to connect RC and test, so far working great.

Edit: The threaded rods are great, allows for easy modifications and changes. I still haven't glued the hull sections together just the bulkhead for the motor mount is glued in place. If the hull was longer the motors could be mounted on the same section as the aft servos.

[Ed Kirk]

Finishing up stern, rudders and planes. I combined the two parts of the upper and lower rudders so they are now one piece each and attached to a common rudder post. Stern planes lengthened to 150%. Also installed set screws to all planes and rudders. Finally got a radio and sorted things out so I can start connecting moving parts and testing.

[RCSubGuy]

[QUOTE=redboat219;n193751]

Loving this project! I have plans to do the same, but with a Type VII to make it more cartooney. Maybe put a cartoon crew aboard, lights, et all...

[/QUOTE.............

That's what inspired me! I have one sitting here on my desk.

[redboat219]

[QUOTE=RCSubGuy;n193750]Loving this project! I have plans to do the same, but with a Type VII to make it more cartooney. Maybe put a cartoon crew aboard, lights, et all...

[/QUOTE.............