[Joecollection18]

the goal in a gif

[Novacaine31]

I just saw some guy post videos of his 1/16 amphibious landing tank (AAV7) on FB. Thought it might give you some ideas or inspiration. It looks like he almost drives it into the ocean but even the small waves are probably too big.

https://www.facebook.com/10000289569...5238122582679/

[Joecollection18]

Quote:

Originally Posted by Novacaine31

I just saw some guy post videos of his 1/16 amphibious landing tank (AAV7) on FB. Thought it might give you some ideas or inspiration. It looks like he almost drives it into the ocean but even the small waves are probably too big.

https://www.facebook.com/10000289569...5238122582679/

thanks! very nice find
i am currently stalled with sealing/water proofing issues. i want to be able to open it up, yet being waterproof while having the openable rear ramp and side doors.
the real vehicle could be fully submerged under water for length of up to 15 seconds. during that, the entire vehicle could tumble but would eventually float right side up. this is where a proper center of gravity and floatation behavior matter. the real thing has also a few bilge pumps to evacuate any water coming in. i played around with a tiny pump but the flow is too slow, requires more power to significantly work.

i can also just wing it.run it like an open top boat. make it somehow splashproof not waterproof. that is a risk to the components. it could capsize and sink.

right now
the current tamiya electronics cannot handle the twin drive motors (tracks)at full power with 2 extra motors powering the propellers/jets.
am wrestling with how to switch from props to tracks and maybe combo ...

[Zap Rowsdower]

Can you safely waterproof just the battery and motor and let everything else get soaked if it was greased up really well first? Like, mount a small otter box with a couple of axle holes drilled into it with some rubber grommets and grease to prevent water intrusion?

If so, then it seems like running it with an open bottom (the area above the tracks being cut away as it is in one of your pics) with a few good-sized weights glued down in the middle would be a good start. Just let the water in freely while using a thin/wide sealed air bladder just under the rear floorboards and a second/larger one filling up the nose. That would give you the ability to adjust the depth of submersion at least a little, should hopefully keep you from capsizing at all, and would definitely prevent a bottom-of-the-sea loss if ever capsizing were to occur. Dirt intrusion would be a big problem after that I guess but mitigation should be possible with a few housings screwed in here and there.

Any of this useful?

[Joecollection18]

Quote:

Originally Posted by Zap Rowsdower

Can you safely waterproof just the battery and motor and let everything else get soaked if it was greased up really well first? Like, mount a small otter box with a couple of axle holes drilled into it with some rubber grommets and grease to prevent water intrusion?

If so, then it seems like running it with an open bottom (the area above the tracks being cut away as it is in one of your pics) with a few good-sized weights glued down in the middle would be a good start. Just let the water in freely while using a thin/wide sealed air bladder just under the rear floorboards and a second/larger one filling up the nose. That would give you the ability to adjust the depth of submersion at least a little, should hopefully keep you from capsizing at all, and would definitely prevent a bottom-of-the-sea loss if ever capsizing were to occur. Dirt intrusion would be a big problem after that I guess but mitigation should be possible with a few housings screwed in here and there.

Any of this useful?

thanks, yes that is an option.
if I could build foam inserts that fill all the negative space inside the lower hull... clean and complex shapes espousing every nook and cranny ... any water intrusion between the lower hull and under the beige tray (the large beige part with the rear floor and seats) would not be an issue. the motors and gearboxes would need some sealing.. feasible but more work.
theory is good, reality is... hard to execute cleanly. having pools of water permanently above seals is a constant risk should they fail. water always finds a way in eventually...

right now I am using the battery as the weight to keep the vehicle stable.
4x Aa or 7,2 nimh pack under the rear floor. the gearbox and drive motors are laying flat in front/middle floor. CG and stability on land and water is great and exactly as desired... for now
(forgot to document)

the other choice is to fuse/glue the vehicle upper and lower hulls. the junction line is barely above water line. water will come inside if that junction is kept the way the toy is.
so i fuse the body halves, and cut the upper deck. the upper deck, the hull upper surface becomes a large plate that is bolted down onto the hull.
easy, straight forward, splashproof... and can add a gasket easily.
what is difficult is the integration of the rear side doors and a newer outline inside jogging around. hatches, engine hatch and square hatch .
this solution would ensure a much better sealed hull so I could venture in somewhat rough water, aggressive splashes without fear of water intrusion.

as a kid, i remember that the warthog problem was that the splashing of water. even if floating well, as more water made its way inside, it would create a sloshing pool inside and that would induce ugly listing and then sinking.
the warthog is getting clear polycarbonate windows (shown in videos) so that splashing water won"t be an issue. it was a lot of work but it's fairly well integrated
.
less talk and more show: videos showing what I got here:
(unlisted)


https://youtu.be/VX16wICPG7U

https://youtu.be/t3mHARPfFSE

[Zap Rowsdower]

I'm talking about a much simpler air bladder, not form-fitted styrofoam. Something as simple as a gallon-sized ziploc bag melted closed so it won't leak or those shipping air pillows that are simple, sealed bags of air. You seem to be in a very formal, tight-tolerance mindset and I'm suggesting something intentionally loose. Kinda how the AKs did better than M16s in the sand because their bolt system was loose enough to let sand tumble back out instead of jamming. Same idea with the water. Let it flow wherever it wants because it's just going to flow right back out in a minute. Your buoyancy is sealed, your motor is sealed, and water has an easy escape route once you're back on the beach. As long as you can keep your power pack and motors dry you don't need to seal or precisely fill anything (in fact you're better off if you don't). I dunno, just something to consider as long as your axles and gears can withstand the water.

I won't beat a dead horse, I just wanted to clarify the strategy.