Another idea I was toying with was making a submarine. I believe it would be a fairly simple matter to contain the electronics within a 1/4" thick Plexiglas tube sealed at both ends with Plexiglas caps. In order to protect the motors I figure an impellor would be a good choice for actuating the propeller rather than trying to maintain a good seal with an axel protruding through the body of the submarine.
Has anyone had any success having a Vex motor coupled in some manner to an impellor
Or cheaper PVC pipe with PVC screw-on caps on the ends.
An impeller is just a propeller in a housing (wikipedia). It seems like the same problem exists with seal on axle.
Another issue for a submarine will be radio range.
And visibility in a natural water. A swimming pool would be ok.
One RC submarine magazine article suggested only diving when headed to shore, or having loss-of-RC-signal failsafe to cause surface.
How do you plan to control buoancy? Thats the difference between a boat and a submarine. What about other control surfaces for flying underwater?
Too solve the rc problem just buy a really long phone cord(the kind the goes from the receiver to the speaker)which should be only 10ft long max but u could cut off the ends of a couple of them then solder them together
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the only thing is it brings out another problem:the cord could get caught on something or ur robot would get stuck.
What about an infrared camera on the front and some JB weld to secure the propeller and shaft? Would some paddles mounted on the sides that could also be used for steering help it remain upright?
Here is a Lego sub I found on the internet a long time ago. As you can see to move up and down it uses a syringe which in pulls in water or pushes it back out. You might be able to use something similar but with a pneumatic cylinder, make your own syringe but only larger. Use the pneumatic cylinder to suck up with the syringe or push out the water. Maybe thats too complicated but hey it could work.
Technically it’s not the taking on of water that would cause it to sink, it’s the compression of the air- the air is in a smaller volume. Air pressure doesn’t matter, just volume.
I was pretty sure subs dived by filling balast tanks with water, I thought they just blew off the air in the tanks, but I guess they could compress it then when they were to surface uncompress the air forcing out the water. That would be what your talking about, I think…
what about 4 motors connected to paddles on the outside and a motor on each paddle with a prop on it this way you could steer, dive, surface and do everything.
I would go with using two props, one on each side, that could rotate independently. Face them both backwards to go straight, flip them horizontal to make them vertical, and anywhere in between. Get the idea?
It might be easier to just get a Submarine RC kit and see how they do it.
Any time there are moving parts outside the sealed box, there are likely to be leaks or sealing issues. Even just steering rudders.
Suppose you take two 5" wheels on axles on independent frames and press them together face to face. You can transmit torque from one axle to another by friction between the wheel faces. Now put piece of paper or transparancy plastic between them, no friction, so no torque transfer.
Now glue small super magnets to each face in an alternating N/S pattern.
Now you should be able to transmit torque through the plastic membrane by magnetic coupling. But I doubt you’ll get much power through it, so the submarine might be more like a paddle boat than a speed boat.