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RDT Rim driven thrusters


(Hardi Hansen) #1

BlueRobotics, you are doing a great job providing open source material and affordable thrusters.
Are affordable rim driven thrusters (RDT) part of your future product plan? Or does anyone know where to get affordable parts for these.
Thanks!


(Kevin) #2

What would be the advantage of one of these types of drives over a conventional thruster with a shaft?


(Rusty) #3

Hi Hardi,

Thanks for the post! I’m glad you like our products!

Rim driven thrusters have a lot of cool features! We’ve definitely consider designing one. We haven’t done a whole lot of work towards that, but there are a few reason why we haven’t chosen to move forward. These could be false assumptions.

  • You need to build a lot of motor tooling from scratch including the stator.
  • The stator and windings will be pretty expensive to make compared to our current design.
  • You need a lot of magnets, which makes the motor inherently more expensive.
  • You need large bushings, which are also expensive and will definitely have much more resistance than small bearings.
  • There are a lot of patents (at least in the USA) focused on rim-driven thruster technology.

That said, it’s still really interesting and we’d love to give it a shot at some point. Just sharing my current thoughts.

-Rusty


(Hardi Hansen) #4

Thanks for the quick replies.

My project involves thruster around 1 meter in diameter. And, generally, at that size you need to use mechanical gear to lower the propeller rpm to an efficient speed. With RDT the numbers of poles in the electric motor can be much higher, and therefore lower rpm are possible at a given frequency.

My interest in smaller rov thrusters is for a small scale prototype of an object for thrusters to pull.

And you are right, the price is the big issue. From what I, until now, have collected, 100mm RDT price is 25 times that of T200. Bringing similarities to BlueRobotics founding history, from the quest for cheaper parts. :slight_smile:


(undersearobotics.com) #5

They are much less likely to foul from weeds, rope, etc.


(Kevin) #6

Interesting, thanks. I had only seen that they were quieter.