I Turned MIT Award Winning Toroidal Propeller Into A PC Fan | Fan Showdown S5 Special

MIT has just been awarded an R&D 100 award for the work they did on toroidal propellers. MIT set out to create a drone propeller with similar performance to standard propellers but while being much quieter. Well spoiler alert they nailed it, demonstrating a Toroidal propeller on a consumer drone that seemed to check all the boxes.

Well..... as soon as MIT published there findings I had tons of people reaching out to see if I had seen the study and if I could turn it into a PC fan.

Well if you know me you know I can turn anything into a PC fan, so today I take MIT award winning toroidal propeller and turn it into a PC fan.

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Material Used Formfutura Galaxy PLA "Jupitar Brown"

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[RealEngineering]

The fan blade has more blades, which also cuts down noise compared to a 2 blade prop. It sounds like you get a decent amount of vibration noise too, which is either because your toroidal isn't weight balanced, or you could have some structural issues. Could figure that out pretty easy in Ansys.

[davidblalock]

Yes a Sharrow Prop is worth it, if you're on the water professionally, or you're a very avid fisherman. You will save enough in fuel in one year to pay for the prop twice over.

[laughingone]

One very big difference is the fans you are testing are ducted. In this case the "duct" is the body of the fan. When Noctua designed their fan they designed it to work optimally within that body. The Noctua fan also has many more blades, with much less open space between them. Therefore it can push against higher static pressure at lower RPM than a typical propeller can.
Remember, the noise of the high speed propellers on a drone mostly comes from the tips of the propellers. Such propellers normally have relatively few blades, so the toroidal propeller is a closer match to that.
Further, the toroidal propeller is intended for use outside of a duct, where the airflow around and through the propeller behaves differently from how it behaves inside of a duct.
In the end, while this test was interesting, it was more like comparing apples and oranges.
If you want a more accurate comparison, consider making a fan with blades just like the Noctua, but with only 3 of them. Then test that against the toroidal propeller inside and outside of the duct.

[dkkoala]

Have you ever tried printing the A12X25 yourself, to truly see if the differences you are measuring are due to the design, or if the print quality also plays into it? I see a lot of ripples in the surface of the prints, which to me seems like it might contribute to turbulence and noise levels. Though i don't know much about aerodynamics so might also be way off.

[victorsteerup]

The toroidal is designed for open air, not a duct. Also, Sharrow used to machine their props out of one huge block of stainless steel, about the size of a 5-gallon bucket. They are now working with cast stainless, to get the cost down.

[Patrick.Weightman]

1:23 That amount of immediate reverse power is ungodly impressive

[asub]

A major difference is that MIT seems to be focusing on wing tip vortices, but your "tip" boundary is different. Instead of being in free air, its in a static ring. So the torodial was optimized for a different set of conditions.

[FrddyMhrCurry]

I think that the Toroidal Prop isnt Quieter than the Noctua also has to do with the fact that in the PC fan mount the Fan is encased with the tips right up to the mount of the fan. That probably combats those tip vorteces wich are much more prevalent in a free Propeler like on a boat or a drone

[glMILAN]

Honestly I think the fact that you were able to match the noise level of one of the best fans in the industry with just a new shape and nothing of the polish work that a company like noctua puts in their product to make sure they are that quiet, I find very impressive!

[eternalsunshine]

If you read their paper, the intent of this was to avoid adding the shroud around the blade tips (ie case-fan)... you might find that their design pushes more air than the noctua fan, if you remove the case-fan frame from both. :D

[oadka]

I think it is really tough to evaluate the MIT design unless they release models. Aerofoils and aero structures are impossible to eyeball and small changes can make significant differences.

[Jossandoval]

I get the feeling that if I hang around this channel for a while I will turn into a fan. One way or another.

[Stant]

I read an article about the MIT thing over the weekend and immediately thought, "Man, it'd be cool if someone made it a fan for this show." Day and a half later, you delivered.

[vibingwithvinyl]

I think that the frame of the A12x25 helps the standard fan a lot. Spinning in free air, it probably wouldn't do nearly as well.

[askquestionstrythings]

The fan "shroud" functions to break tip vortices like the Toroidal Propeller, so it makes some sense that the Toroidal Propeller doesn't make additional improvements in a shroud. Toroidal Propeller is really a design that improves shroudless fan/propellers. As others have mentioned, more blades for the A12x25 is also likely to be better over the 3 blade design in the case of a shrouded fan for both air movement and noise.

[GrumpiestKitten]

The noiseblocker eloop did this years ago. They also quoted the reduction of tip vortices as the main advantage.
Loop rotors where initially patented by Dr. Rudolf Bannasch in 1999, see EP1196696B1 or WO2001002742A2 (Rotor with a split rotor blade).
The patent recently expired so I'm not surprised that a lot of people are "inventing" this now.

[_chpset]

What I find fascinating is the suboptimal build quality and speed of design was able to nearly match the noise performance of the noctua fan, which is about as good as it gets. This might actually have potential with more R&D

**Edit**
Yall, I'm not a fluid dynamics expert. Idk why this comment keeps getting replies. It's an interesting topic for sure, but Idk wtf I'm talking about.

[NondescriptUsernameUnlocalizab]

As others have pointed out, the vortices concept is reduced in significance when the fan is ducted and not open like a drone propeller. The blade area ratio between the two tested is also massively different, you'd see better airflow from the toroidal if the BAR were higher. Overall it's actually really promising, especially given it shifts the sound profile to lower frequencies, which are far less annoying.

[bluej]

I'd love to see this on a drone with a sound test, see if it even works lol.

[RotGoblin]

The longer this Fan SHowdown goes on, the more convinced I am that Noctua really do know their sh*t.