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My latest build is a new version of the Turtle.
Nope, not the one you are thinking of, this is of a Green Sea Turtle! I carved a set of master molds in wood for the shell, head, tail, flippers, and used Smooth-On silicon rubber to make molds from those.
The molds were used to cast fiberglass parts, which were then painted up to match the colors of a real turtle. The top and bottom of the shell are seperate, the head is one hollow piece, and the flippers were done in two halves to make them hollow.
For best maneuverability, the props are mounted in a gimbal mechanism, to give steering and diving controls.
To get the WTC as small as possible, I designed the arrangement in Fusion 360, so I could rearrange the components till it was a layout that worked. There is a single motor driving the two props through a toothed timing belt, two servos for the prop gimbal, and one more for the front flippers.
After a ballasting session in the tub,
it was time for sea trials at our monthly meet at the Y pool:
It worked well for its initial run, just a few tweaks needed for next time. The top surface of the shell tends to push the 'bow' down as speed comes up, just like the Flying Subs tend to do, so I am going to pitch the head/neck up and repitch the tail flippers to compensate for that. It has a decent turning circle, and the gimbal worked quite well.
Here are some videos (thanks much to Greg and George for the cameraman duties!)
Quick clip from underwater:
Couple longer movies of first run in the pool:
Nope, not the one you are thinking of, this is of a Green Sea Turtle! I carved a set of master molds in wood for the shell, head, tail, flippers, and used Smooth-On silicon rubber to make molds from those.
The molds were used to cast fiberglass parts, which were then painted up to match the colors of a real turtle. The top and bottom of the shell are seperate, the head is one hollow piece, and the flippers were done in two halves to make them hollow.
For best maneuverability, the props are mounted in a gimbal mechanism, to give steering and diving controls.
To get the WTC as small as possible, I designed the arrangement in Fusion 360, so I could rearrange the components till it was a layout that worked. There is a single motor driving the two props through a toothed timing belt, two servos for the prop gimbal, and one more for the front flippers.
After a ballasting session in the tub,
it was time for sea trials at our monthly meet at the Y pool:
It worked well for its initial run, just a few tweaks needed for next time. The top surface of the shell tends to push the 'bow' down as speed comes up, just like the Flying Subs tend to do, so I am going to pitch the head/neck up and repitch the tail flippers to compensate for that. It has a decent turning circle, and the gimbal worked quite well.
Here are some videos (thanks much to Greg and George for the cameraman duties!)
Quick clip from underwater:
Couple longer movies of first run in the pool:
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