Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Engineering Techniques and Materials. => Topic started by: Colin Bishop on February 10, 2023, 05:52:36 pm
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Just came across this video about toroidal propellers which are claimed to be far more efficient than standard ones although a lot more complex to make.
Does anyone know if they have been experimented with on model boats?
https://www.youtube.com/watch?v=MGy8jvf-DZ0
Colin
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I’ve heard of them and seen the design a few years back. I’m sure a fellow WP club member did enquire Prop Shop about making one for a model but I don’t think anything came of it.
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It would be interesting to see how such a prop is manufactured
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It would be interesting to see how such a prop is manufactured
They do touch on that in the video - CNC machined from the solid or 3D printing. But currently 10x the price of a standard prop.
If someone were to create the design, a 3D printed prop for model boats would be perfectly feasible, although I suspect the number of variables - pitch, blade area, size of aperture - means an awful lot of trial and error would be needed to find a workable design. Anyone up for the challenge?
Greg
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A guy at my club has been experimenting with 3d printed plastic props for some time now, though he’s yet to get one that lasts more than a few minutes of run time
If someone does design a toroidal prop then I’m sure that the guys at rc-prop.de would be happy to mill it
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They are very complex shapes. As Greg says, a lot of experimentation would be needed to explore performance options. This would seem to suggest that you would need to have a 'tweakable' CAD pattern and access to a 3D printer capable of printing metal. Presumably you could start with a scaled down existing full size power boat design. (if you could get one!)
I think Prop Shop propellers are generally cast rather than milled but I stand to be corrected. Mine are.
Colin
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Prop shop items are investment/'lost wax' castings.
Can't see any reason why these toroidal props couldn't also be cast.
There is also the option of having them 3d printed in metal.
Some designs are on thingiverse.e.g. https://www.thingiverse.com/search?q=toroidal+prop&page=1&type=things&sort=relevant
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Mmmm...??? Similar to the Spiral propellers used on CMB's during WW1. In this case it was to prevent getting entangled with netting and barriers whilst making torpedo attacks. Apparently they gave much the same performance as a conventional propeller.
Glynn Guest
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See: https://youtu.be/w90gM7bGdvk
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Sundogz found a 3d STL, for high speed marine use, on Thingiverse, by SapoLAB-DIY (https://www.thingiverse.com/SapoLAB-DIY).
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https://www.thingiverse.com/thing:4625856 (https://www.thingiverse.com/thing:4625856)
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There is now a full sized electric outboard available, with one of these props
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Now that propellor is a work of art... And I guess milled out of stainless Steel.