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Project "Sea Turtle" (formerly known as "Hammerhead")

Discussion in 'MA' started by Drew, Aug 26, 2018.

  1. Drew

    Drew Carbon Fiber Dust

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    WIP, but the experiment goes well.
    Was just shooting some ideas back and forth with Rangga at team flash and somewhere in between I got the idea for an amphibious mini4.

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    It's not sitting on anything in the water.....really!

     
  2. ltr74

    ltr74 FRP H-Bar

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    Tamiya makes a submarine kit that could be used for propulsion in the water. Part number 70153 or 70185.
     
  3. Drew

    Drew Carbon Fiber Dust

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    I don't want to do that though :)

    I'm going to make some custom paddle tires, like the kind on dune buggies.
     
  4. ltr74

    ltr74 FRP H-Bar

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    It was more that it had a propeller system that ran on a 130 motor that could be adapted to help it move in the water.
     
  5. Drew

    Drew Carbon Fiber Dust

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    I know, I've seen them, but I wanted to avoid using a propeller system, relying solely on the tires, hence why I'm going to make some custom paddle tires.

    Anyway, started the next stage, building the side walls.

    I've trimmed each corner of the battery bay to make it easier to apply the plasheet and seal it.
    I then added the tail cover first and trimmed before attaching the wheel panels.

    Later I'll fill the gap, add a horizontal panel that will fill between the wheel arches and also mark the arches.

    After that will be making the wheel arches, putting a temp wall front and rear so I can float it for depth and finally cut the walls down and shape.

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  6. SignOfZeta

    SignOfZeta Spacer

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    Stomper did this back in the day. Water Demons, they called them. They didn’t do much of anything to the chassis really, they just used HUGE airtight hollow plastic wheels with rubber paddles on the rubber band thick tires. That way they float upside down even.
     
  7. Drew

    Drew Carbon Fiber Dust

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    I've seen a mini4 with the same principle using ping pong balls. Still, that's not the kind of thing I was aiming for.
    Think of it something like this:
    500_hoot-1.jpg
     
  8. Soybi

    Soybi Spacer

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    any update regarding this amphibious MA chassis project? :) kind if curious about the result since I saw a vid on youtube about japanese racers racing underwater with their mini 4wd by sinking half of their race track underwater.
     
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  9. Drew

    Drew Carbon Fiber Dust

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    Sorry man, I've been a little short on money recently and it still needs bearings. It'll probably be a couple more weeks until I can buy some, then I'll look at getting back to it. That said, I did finish off the tub so it floats but forgot to post images it seems.
    I've been able to float it safely with a weight of 200g. Really don't know what to do about the top once it's done, no shell fits and it'll be hard to make something that looks good.



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  10. Soybi

    Soybi Spacer

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    looking good. you can try cannonball cowl and just screw it to attach it haha! since it looks like the best cover for amphibious car. would be nice to test on a river :D
     
  11. Drew

    Drew Carbon Fiber Dust

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    Still wouldn't look right, I've got a poly rowdy bull and even that looks tiny sitting on this. Anyway, need to get it working first :)
     
  12. Drew

    Drew Carbon Fiber Dust

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    First update on this in a while. Just recently bought a whole bunch of bearings, which will quickly be gone >.<
    Anyway, here's the idea for the amphibious, I need to make a joint that's sealed from the water. The best way I can think to do this is to use 2x bearings with rubber seals per wheel. Setup like the first image bearing, small rubber tube, bearing, small rubber tube. And then add a large rubber tube over the top of both bearings and glue it to the chassis. This should make a water tight seal and keep water out of the car.
    20181226_160553.jpg 20181226_160803.jpg
     
  13. Drew

    Drew Carbon Fiber Dust

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    So I finally got the amphibious working, was called project Hammerhead, but given how it looks now, I think project Sea Turtle seems more appropriate.

    Anyway, I began by putting the bearings in as normal, then adding the large rubber tubes over and gluing them to the chassis.
    I then added a small ring made from the small rubber tube, followed by bearing, another small ring and finally the wheel. You can now see the whole underside is done.

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    I then rigged up a switch and glued it in at the front, it sits low enough that I could make a cover that just slips on top and won't be affected by the switch.

    20181226_191104.jpg


    It's weight with batts is 153g, but the car can float at upto 200g successfully. I tested it in the bath hence the audio and my breathing sounding really loud, sorry for that. In the last image I've marked how deep the water was.

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    I've tried to show in parts of the video that there was no water ingress via the axles in this setup. I already know from previous tests that the rest of the chassis is water proof.




    Don't know what I'll do for a shell though now....I'm really not that creative art wise. I may take it out to the ponds at some point, although I've no idea how I'll retrieve it if it gets stuck in the middle or stays doing circles in the middle.
     
  14. Drew

    Drew Carbon Fiber Dust

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    Making a mess....also making some large wheels [​IMG]

    Started making a top frame for the amphibious, I've also added a rudder to the rear hook for the top frame in order to control the car direction in water. I've added a couple little bits of plascard to keep the rudder in correct position.


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  15. Drew

    Drew Carbon Fiber Dust

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    Underwent trails today.
    Grass trials
    Mud trials
    Stream crossing trials
    Sea trials

    Finally got it's stamp of approval:

    istockphoto-642961072-612x612.jpg

     
    Last edited: Feb 10, 2019
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  16. David S.

    David S. Spacer

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    That's hilarious. Love the British stoicism on display here, Drew :). Great effort and impressive engineering/buoyancy skills on display. Perhaps some kind of mini-minesweeper is needed for the next sortie...? :)
     
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  17. Drew

    Drew Carbon Fiber Dust

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    Or maybe some fishing waders :p
    I'm happy in the end, it worked well and didn't have any leaks. Shame about the bearings though, it's the only thing that saddens me, 8x good bearings now gone to waste but oh well.
     
  18. SignOfZeta

    SignOfZeta Spacer

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    Man, that was pretty fun. I’m sorry it wasn’t at least a little more successful.

    Earlier I mentioned Stomper’s Water Demon line which had huge hollow plastic tires with rubber paddle bands wrapped around them.

    Since then I’ve learned that Takara had a series of “suirikuzenku” cars (sea and land) that did the same thing. They had what looks like a way better tire design though. I’d crib from the Takara design, personally. I would link to a popular Mini4WD site with pictures but I’ve already violated the forum rules by uttering the name of a rival company who sorta competed with Tamiya in this area 30+ years ago.
     
  19. Drew

    Drew Carbon Fiber Dust

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    Give me link in PM then, I'd be curious to take a look at the cars and tyres.
     

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