I have not found anything on the toroidal propeller for model boats. The smallest I found was for trolling motors (3D files). It seems this modern version design was released in 2022 by MIT Lincoln Lab.

Lew
Florida, U.S.A.

HI peter, I think that's more up your alley, - I'm not that clever. I was however thinking of a similar thing for aeroplanes many years ago, but as a closed vented conical shape, (like a big propeller spinner with progressive turbine blades inside ). Would need some clever engineering to produce one to try, (3D printing might work these days)

JB

Found some vids on them which might help.





JB

I also print my own props, so I was asking if anyone else had tried to do this and if it works on small (model) boats.

Lew
Florida, U.S.A

Sounds like a good project for 3D printing. A lot of folks print their own impellers for water jets in both plastic and metal.

Just looked up this type of prop. Interesting and much quieter than traditional airborne props so probably being driven by the current rise in drone use.
Other benefits are reduced fuel consumption and faster speed so possibly more use for the fast racer modellers.
Complex and costly to design and make so I am not surprised to hear they are possibly not available in model form but I'm sure they will appear at some point.
Always good to hear of evolving technologies, so thanks Lew
dave976

Having used on real boat I have tried to find model version but so far no luck. Very impressive performance over standard props on my mercury 100's and good fuel saving.
Cheers Colin.

Sounds like you might just have come up with a new project for JB. He, like Graham, like to try new things.😃

Hi Lew.
I must be honest and say that up untill reading your post I have never heard of such a prop.
I will read up with interest.
Regards
Bill.