FTFC'18 WWII - Ushakov LPL Flying Submarine by FoamyDM


Building Fool-Flying Noob
I know this Thread has been dormant. but I have two Flying Submarine Models sitting on shelves in my bathroom reminding me every day how this project is not complete.

OK, Sometimes, when you hit a wall-like obstacle, you have to pause, look around, and pivot. or just pick up and work on a completely different piece of the puzzle.

I that effort, I have been looking at and very interested in, submarine builds. Now as mentioned before The Nautilus Drydocks run by Bob Martin, THE RC Sub Guy. It is one of the most abundant and useful sources of RC Submarine building information and tutorials that I have found on the internet so far. When I started this journey, I have had his help in determining which Diving system would fit best with the project. The RC groups thread has wisdom as well, so don't count it out.

Bob - If you are seeing this, I still am indebted to you for the knowledge you have passed along. You continue to inspire me.

Since this project hit the wall, Bob has released a few 3D print your own models in hopes to expand the hobby. I purchased one, but then my printer at the time stopped.

about a month ago, I was perusing www.thingiverse.com for Subnautica (an Immersive Water-based Computer sandbox Game) things, I saw it has inspired T Zero Systems to make a Working 3d Printed Cyclops Class RC Submarine. As I had a Whole spool of yellow PLA filament, it was time to take a journey.

I am going to build my very own RC Submarine.

I downloaded the parts began printing.
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While printing, I also went on Amazon and ordered all the parts I needed. (links and list is in the Thingiverse Write-up.
As with all thing semi-autonomous... Sometime things don't quite work our correctly. This piece had a filament get caught, so it was under extruded
It uses a traditional Quad motor setup, of which I have those, but the ESC is rated for more amps as the propeller creates more work as the fluid is much denser, so I ordered a 45A servo for the 2204 2300 kv motor.
Otherwise the servos are typical 9g servos. 3 is all that is needed, (rudder, Dive plane/elevator and the Ballast controls. I am considering putting a servo for pan functions... but that is a future expansion.
The front dome is a CCTV Camera dome. Cheap easy to find.
I plan to use Corrosion X HD for the servos and ESC and RX and Camera components.

Signal and Waterproofing.
75mhz or an old Plane 72 mhz radio is able to transmit through water, however, 2.4ghz, or 5.8Ghz cannot. I can use the old transmitter I purchased for the project, or make the conning tower/sensor array a detachable signals buoy, that trails behind the craft, floating on the surface. I would use an SBUS receiver to a Flight Control and an RX for the FPV system powered separately, with a vid line to the water proofed camera.
Printing and Water - Another issue is the 3d printing will take in water if not sealed. XTC-3d resin system has been used to seal the printed parts inside and out.
It is important the part not take on water, or the carefully balanced system will end up heavy and possibly not return to the surface.

Emergency buoyancy. it is possible to include a CO2 cartridge that is punctures in a continuous fail safe or power off situation. the would inflate a sac to ensure the submarine floats to the surface. Like a life raft.
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Building Fool-Flying Noob
In an effort to remove these two planes (see last post) from decorating the bathroom, I decided it was time to see what it would take to submerge the models.

So I filled the garden tub (just big enough to fit the plane) and pulled out my soup cans and scale, and got things wet.

just for fun, I wanted to remind myself how much airframe weighted, I found it to weigh ~265g.
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Then I dropped the plane in the water. PLOP! and saw that it sat pretty in the water. What I was aiming for was to see where it balanced, and what is the buoyant force. I went to the pantry and pulled out a range of cans ranging in weight from 4oz, to ~2lbs. IMG_20210811_180807565.jpg IMG_20210811_181319432.jpg IMG_20210811_181224203.jpg IMG_20210811_181337648.jpg
I began loading it up. the 2 lb can barely did anything. then a 2nd large can, then a 3rd. now the wings were submerged and a bit nose heavy. time to add tail weight. Now it was at a nearly submerged fuse and as it was top-loaded, it was getting very... wobbly.

It took 1 more can to fully submerge the fuse, in both attempts this is where the plane de-stabilized and I had to retrieve the cans from the water and weigh them. nearly 3.4kg!
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I doubt I will be able to get that kind of weight (3.7kg) into the air with a ~40" span plane. This confirms that I need make this model from material that is much closer to the density of water. Fortunately, that material is already used to make planes - Plastics.

Plan 3 revision:
Build a slightly bigger plane from Coroplast sign material. The big issues and excitement is it will be a new material to work with, but it will be all-weather, and still light weight enough, also the gaps can be reinforced with Carbon Fiber to increase rigidity.
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