The MIT Lincoln Laboratory is developing near-silent toroidal propellers!

[Christophe]

If the thrust and propulsive yields are the same, it's amazing!

Screenshot 2023-02-02 at 19-09-58 TVO_Technology_Highlight_41_Toroidal_Propeller.pdf.png (437.3 KiB) Accessed 967 times

Screenshot 2023-02-02 at 19-09-48 TVO_Technology_Highlight_41_Toroidal_Propeller.pdf.png (118.23 KiB) Accessed 967 times

https://www.ll.mit.edu/sites/default/fi ... peller.pdf

https://superinnovators.com/2023/02/nov ... ess-noise/

Future Dragonfly propellers?

ps: almost silent... according to the videos... I didn't find any indication of dB at equivalent thrust...

MIT report (summary):

TVO_Technology_Highlight_41_Toroidal_Propeller.pdf

(1.45 million) Downloaded times 3

[Christophe]

It also works in hydraulics (the sound of the propeller travels that much in the air??)

https://newatlas.com/aircraft/toroidal- ... ropellers/

[Petrus]

We won't even hear the killer drones coming to eliminate us, great!

[Christophe]

After :

(all is not true)

[Christophe]

The comparative yield curve...what explains the fall and rise in yield? Cavitation?

marine propeller toroidal yield.jpg (85.23 Kio) Consulted 483 times

[Christophe]

I'm going to test 3D printed toroidal propellers on one of my aero test benches...

Here are some models:

6 blades: https://grabcad.com/library/toroidal-pr ... -6blades-1
4 blades: https://grabcad.com/library/toroidal-pr ... 4-blades-1
3 blades: https://grabcad.com/library/toroidal-propeller-2
2 blades: https://grabcad.com/library/toroidal-pr ... 2-blades-1

Well, this will take a little time... To be continued!

[Remundo]

the idea seems very interesting to me.

It is the same approach as the winglets in aviation.

We prevent the wing from "terminating" and in doing so, we reduce the wingtip vortices.

I can believe it decreases noise, and maybe even increases performance.

So maybe there are other downsides, does it increase the drag of the spinning blades?

Apparently the inventors are confident and announce record yields.

To be continued.

[Christophe]

Well, the best thing is to check for yourself and I have all the tools at hand: 3D models, 3D printers and aeronautical test bench! So why deprive yourself?

I think the comparative efficiency is better in hydrodynamics than in aerodynamics...and I don't really believe in Santa Claus: submarine manufacturers have been working on (the sound level of) their propellers with billions of budgets for 80 years ...and they would never have discovered this hydrodynamic "trick"?

Yeah...to be continued!

[Macro]

Have you seen a military submarine propeller in use?

I think it's a part of their "anatomy" that we try very hard to keep secret

[Christophe]

Well shit, I'm stupid !!

Come to think of it, I already printed one a toroidal helix for testing in my stream 2 years ago...I had found this model on https://www.thingiverse.com/ well before MIT communicated on it suddenly!

I just found the 3D print in my "archives", the toroidal is 225 mm and the classic 200 mm.

thoroidale_hydro.jpg (122.36 KiB) Viewed 192 times

Well comparatively in the stream...despite its 25 mm more on the diameter...the toroidal, this is big shit!

The torque was much lower than the other for the same water speed!

So I'm less motivated to do aero tests...