Quiet toroidal propellers -- beautiful, too

Toroidal propellers: A noise-killing game changer in air and water

By Loz Blain, New Atlas, January 26, 2023

These strangely-shaped twisted-toroid propellers look like a revolutionary (sorry) advance for the aviation and marine sectors. Radically quieter than traditional propellers in both air and water, they’re also showing some huge efficiency gains…

We’re fascinated to find a couple of groups claiming they’ve demonstrated significant advantages in both air and water using a markedly different shape – specifically, strange twisted-toroid ring shapes that appear not only to be much, much quieter than traditional designs, but so much more efficient, particularly in the marine space, that they could mark a profound leap forward…

“The key thing that we thought was making the propellers quieter, was the fact that you’re now distributing the vortices that are being generated by the propeller across the whole shape of it, instead of just at the tip,” says Sebastian. “Which then makes it effectively dissipate faster in the atmosphere. That vortex doesn’t propagate as far, so you’re less likely to hear it.”… [end quote]

Quiet, more efficient propellers would impact manufacturing in the commercial and military sectors.

Efficiency and noise are issues for outboard motor props. But commercial shipping vessels might potentially cut down on fuel consumption using more efficient props.

I could see the noise reduction having a huge impact on both civilian and military drones. Delivery drones would be less annoying. Military drones would be harder to detect. If I were the inventor I would apply for a DOD research contract to optimize the complex prop.

I also think these props are beautiful. The photo of the bronze toroidal prop at the start of the article could be exhibited at the Museum of Modern Art. Form plus function.


Quiet propellers are important for the US Navy, particularly with the submarine fleet. Sound is how submarines generally find and track each other. The quieter the submarine, the more stealthy it will be. From what I understand, when a submarine is in dry dock, they cover up the propellers, so the particular shape of the design cannot be photographed, lest it fall into potential enemy hands.

  • Pete