MIT Toroidal Propeller Testing - Performance, Efficiency, and Response - PETG + PLA

In this video I test the two Toroidal Propeller designs published by @STRIKINGFPV , which is based on the MIT designs recently winning an R&D award for claiming the propeller reduces "annoying" high frequency noises. Lets see how they perform.
Designs found here:
www.thingivers...
Automated Motor Testing Methodology:
• Recursion Labs - Fully...
HQProp T3.5x2.5x3 Testing: • New 3.5" Propeller Kin...
Summary of all Motor/Propeller testing: intofpv.com/t-...

[@STRIKINGFPV]

Dude, the analysis you've done here is fascinating and way in-depth, thank you for putting it through the wringer. Not sure what to make of it at the moment, but I'm thinking more and more that the pitfalls of 3D printing are also hindering performance a fair bit, such that I'm considering designing a regular prop using the same blade profiles in order to get a "fairer" comparison. Still not exactly fair, since it seems toroidal may forever by crippled by needing to be 3D printed or machined because of the complex shape which makes injection moulding maybe impossible. At least FDM seems crippled, I'm still waiting to see if anyone gets a nice and durable resin print, or a sintered version.

[@RecursionLabs]

Hey bud. Thanks for publishing the designs. I managed to get the PETG prop smooth where it contacted the air by using really high grit sandpaper to shave of any imperfections it had, but the limiting factor here was flex. With PLA the print actually came out extremely smooth with 1.4mm layer heights and was stiff (which is why it shattered under load), but yeah there is only so much you can do with a FDM printed prop expected to spin at over 35,000 RPM. I do question if this is concept is actually viable though for two reasons. The first being the extra weight needed to create the shape that isn't contributing to providing thrust, which would make it hard to make it efficient comparatively. The second is the data MIT did release, or rather, didn't release. The data they released was primarily focused on the frequency of the noise the propellers made, and they published frequency analysis. They showed thrust stands that use, and it is made by the same company with the same capabilities as mine, so they absolutely would have been able to and very likely captured detailed data during their tests. They chose not to publish it, and there is probably a reason.

[@STRIKINGFPV]

@@RecursionLabs Then maybe we'll be jumping headfirst into that mysterious secretive reason 🤣. Bench tests aside, a few others have printed and flown the V2s and discovered that in flight they're alright, although @willitmod noticed some odd quirks like altitude drop in turns but increased lift in forward flight. I wonder if that will further play into the current pros and cons.

[@RecursionLabs]

@@STRIKINGFPV Interesting. Data from static thrust is really useful, but its limited on some aspects of flight characteristics because of the fact it's only static air. I'm watching closely to see the flight testing the you and the community are doing. Regardless of the outcome, exploring new avenues and pushing boundaries in an effort to make improvements is half the fun of this hobby.

[@nothingnormalnet6588]

@@RecursionLabs This was the best effort I've seen so far in terms of actual science & data is concerned. Thanks for putting it together. I keep proposing that folks who do these tests print a duplicate of gemfan (or whoevers) stock prop so that we can see apples to apples, at least mitigating some of the print/material shortcomings. I wonder if you could print in NylonX or some alternative that is rigid & strong but thin enough to be an efficient prop. It may be better to test only resin prints which will probably blow apart at higher rpm's but at least you could capture data up to that point to imply some valid performance comparisons.

[@mjodr]

@@nothingnormalnet6588 I agree, different materials need to be tested. For some reason everyone just grabs the spool of PETG for their new project, but I think there are better options. Great idea about printing a Gemfan clone to see how it degrade performance over the injection molded polycarbonate+special blend they use.

[@Wild_FPV]

Seems like this concept is going a little bit viral! Unfortunate that they didn't perform to our standards. Maybe a comparison between 3D printed conventional props and these 3D printed toroidal props could be a better one? Very interesting and informative, thank you 💯

[@b3owu1f]

Haha..that's what I just posted.. didnt read your comment. Yah.. I think the material + roughness of 3d prints vs the props you can buy which are smooth.. and probably better material for props.. is making a difference. I'd be curious how 3d printed regular props compare.

[@forestromper]

Yeah, the quality on this print leaves a lot to be desired. I think they could have done a lot better with it, and it should definitely be compared to different prop designs with the same print quality.

[@NicholasDWilson]

I'd love to see this kind of analysis include a 3d print of a traditional prop design to determine how the filament texture on the blade affects performance

[@kaizendon6237]

My thoughts exactly, and my gut feeling is that 3D printed props suck BIG TIME!

[@johgude5045]

yes, then they could call it "science"

[@zblurth855]

@@johgude5045 the MIT did show they also 3d printed the prop and still claim all the good thing. So testing it by 3d is absolutely fair. Now it would be nice to have more data but even now the comparison still stand

[@johgude5045]

@@zblurth855 you think testing an extruded prop against a 3D printed one is fair? Have you ever seen a university from the inside? These video does not proof that the design is flawed, it just proofs that 3D printed props suck

[@focom4546]

@@zblurth855 one thing to keep in mind, university labs have access to industrial 3D printers that are worlds more advanced than anything a hobbyist would have, we're talking like $100,000+ machines. I used one as a student 10 years ago and consumer printers today still come nowhere close. I'd imagine a prop made by one of those could have significantly better performance than what we see here

[@ericbenjaminjr]

Useful or not, as a newbie, I have to say I’m most impressed by how this has brought this unique community together in it’s nerdiness. I mean, I’ve even been slightly bullied for bringing it up in some small, weird isolated communities. But the majority has got me really excited about the hobby.

[@RecursionLabs]

Welcome home. This part of the hobby is half the fun in my opinion.

[@RecursionLabs]

Sorry I had to post this a second time since I had to fix the audio.

[@tytorobotics]

Very interesting results! Thank you for providing such in-depth analysis. Cool that you used the Series 1580 thrust stand like they did, it would be really interesting to see how their results compare.

[@RecursionLabs]

I agree. It would have been great if they published their data, since they'd have been able to capture quite a bit using that stand.

[@jimbarchuk]

It works, so do circular wings, but that doesn't make them practical/doable. Diminishing returns -- adding mass without improving any other feature. The prop you made with the deeper chord, could be extended further to make essentially a multiblade Archimedes Screw. It'd work well moving water, sand, they're used that way now in food processing. But not for moving air at high speed.

[@seb-depp]

Very interesting. Wonder how much of the bad performance results from the fact that they're 3d printed and not as smooth as the compared traditional prop. A sound test at the same thrust levels would be interesting.

[@supyrow]

It's a scam.. a 35 year old scam . It just came back is all

[@RecursionLabs]

I don't have a proper DB meter (I probably should get one at some point), so I didn't want to give data recorded on a phone app, but suffice it to say they are significantly louder than the other prop. I'd estimate closer to a full sized 5" propeller based on the level of ear pain, and that was only up to 80%. Less screechy? Sure, but DB matters more in my opinion.

[@seb-depp]

@@RecursionLabs Interesting. For me it wouldn't have needed to be scientific, just hear it...

[@TorontoFPV]

Oh and Boom congrats on 1k!!!!

[@JustInTime0525]

Didn't notice any issue in the last video, but don't mind watching it again. Love your informative videos and hope we can buy your sub 250 freestyle as a BNF in the near future!

[@RecursionLabs]

If there was a manufacturer crazy enough to make and sell a naked Vista BNF build, I'd gladly donate the designs just so more people can experience what a high thrust to weight 3.5" HD experience is like.

[@JustInTime0525]

@@RecursionLabs Flywoo has a couple BNFs with naked Vista like the Firefly Baby quad HD and Nano Baby 2S, on top of bringing community builder Dave C's Explorer design to the market with huge success!

[@Kabab]

Good work. This is much closer to the reality I was expecting. These are still just bench tests and of crude designs but absolutely not anywhere close to the promise so many expected. Still a novel and intesting direction to investigate. I personally believe a traditional blade with a forward swept outer end behind another blade with a back swept outer end, with the ends connected by a short connector may be a much better way to go. Specifically because forward swept end is going to be more efficient and quieter, just hard to manage the forward sweep under load without fluttering. So if there was a blade in front stabilizing it, we'd get some benefit. Resulting ~4 blade prop with 2 pairs of connected blades might be close to a triblade in efficiency and we might get other benefits we don't know yet.

[@RecursionLabs]

Appreciate the comment bud. That is an interesting idea. We've come a lot way over the past few years (especially with sub-250g propulsion options), but I think there is still a lot of room for improvement with propeller designs in general, especially for specific lengths where we don't have a ton of great options If you ever want a design tested, reach out as I would be more than happy to help.

[@mjodr]

You mean like the Sharrow design? Edit: Nevermind. I think I see what you are describing. But if I squint my mind's eye hard enough it starts to look like these toroidal shapes again! haha

[@hesher.]

A regular 5 blade propeller is much quieter than a 3 blade propeller. Noise reduction and greater thrust also improve with more blades, but the load on the motor increases. This seems to explain the effect of these propellers. It's just a different design doubling the number of blades, with more extra mass at the ends. On motors with a power reserve, thrust will increase, due to increased consumption and the efficiency of grams per watt will noticeably decrease

[@sinisternm]

These things are everywhere. Seems like we're all champing at the bit for something new.

[@francisdaoust5862]

Honestly, that a great channel. Thumbs up😛

[@american7169]

Found this channel cuz I pulled a pad on new FC, friggin love the content! I have a request for motor testing. 1203 flywoo pro v2 nin 5500kv vs emax eco 1404 6000kv. I swapped to 1404 recently for a bit more power but I'm left very disappointed. I saw no power gains and my amp draw went through the roof, killing my flight times. Same props, frame, fc, batteries, everything. I can only go by feel, I want your testing "for science"!

[@ManjaroBlack]

We need to have a ‘fan showdown’ season of toroidal props.

[@redbaron07]

Only Fans!

[@AlfieDoug]

Give it a couple of months and these will fade into a distant memory, if they are so good every helicopter and plane would already be using them.

[@dougkrahmer7468]

The 3D prints look pretty rough and likely cause a lot of air friction. It would be interesting to see what results you get if you 3D printed all of the props in the tests.

[@hifinsword]

Or if the 3D printed toroidal prop was sanded as smooth as the standard prop.

[@chrisbee5481]

Thanks for showing the results on your thrust stand. I've been through just about evey prop from 40mm to 7' on the market. Of course matching the motors and builds. All just to find a quiet fast drone. My results match pretty much what quadmovr praises as whisper props. The HQ 6 and 8 blade props are most silent. Just keep in mind you cant really just use a tri blade setup and put on a heavy, high pitched 6 blade prop on. The motors wont handle them. My rule of thumb would be to go down 1" on prop diameter. Or go up with motor seize with lower kv. I mean having silten props was the whole intention for these toroidal props right...

[@RecursionLabs]

That makes a lot of sense. When you increase the blades two things happen. First the prop can't spin as fast (less RPM) because it it has more load, and with less RPM you can produce the same thrust as a prop with less blades, and a lot of the sound profile comes from the speed the prop is spinning at. The typical downside is less efficiency, and bigger motors.

[@redbaron07]

@@RecursionLabs Exactly, I believe that in Germany they made Cessna owners retrofit 3-bladed props for noise abatement, but the most efficient (thrust per Watt) prop would have a single blade if the motor can provide the higher RPM - some powered sailplanes have those.

[@personious_k]

This is great, thank you. Have you seen projectfarm's comparison videos? You should show your tests and do some things like him. All the same, super awesome, thank you!

[@RecursionLabs]

Yes. Project Farm is a hero.

[@jonbeno9926]

It's really tough to compare the standard propeller to toroidal and be fair. The disc loading should be held constant when comparing noise and power, it's not clear whether that was done in the MIT study. The weight and moment of inertia of the toroidal prop seems clearly higher, which as you find increases the response time and reduces thrust bandwidth. The toroidal design effectively has massive winglets connecting adjacent blades, so it seems reasonable that noise would come down in an apples to apples comparison, but it's very unclear if performance to weight and moment of inertia would ever be competitive. It's really fastenating to me how viral this concept has become. Thanks for attempting to put some numbers to it!

[@mykofreder1682]

It has more surface area wrapping so it will have more air resistance, 1/3 of the loop is providing nothing to the motion and may actually be presenting a much greater cross section in the direction of rotational motion. One tester said it is more stable straight ahead and that cross section in the rotational motion may be adding prop centering force. The warping and blown-up prop kind of says the rotational force on those blunt outer ribbon edges is great. I would have 2 standard prop, slightly curved, shapes and connect them with a circular cross section curve instead of the vertical flat to reduce the cross-section air resistance of the connecting piece, I would also reduce the hub size. Actually, the hub with 6 blades and no wrap around would be close to the toroidal props I have seen on larger planes, it probably would weigh the same and be more efficient. The best approach is to get some type of 3-D finite element propeller modeling and concentrate on the rotational forces to increase the vertical force and reduce the horizontal, and you probably would end up with the 6-blade toroidal prop.

[@jeffswope1511]

If they only performed as good as they look. Nice test setup thanks

[@babytab9809]

Nice work! I put a model you could look at in the Mini 3 Pro Forum on DJI site. The post is labeled toroidal propellers. Right now I just have a double prop posted, but I did design the triple as well, I wasn't going to print it since I liked the double ones better, but I think my profile is more standard and much lighter than the ones you've tried so far.

[@KrotowX]

Exploded like Eachine Wizard X220 magenta stock props. Those was prone to explode on high RPM too :)

[@mjodr]

and floppy proppys

[@woopweep9605]

Thanks for putting this idea to rest. As someone else said, I could see how this would work fine in water as it'll spin up pretty slowly anyway while being fully surrounded by water but for quads we need quicker response and if slow response isn't a trade off for efficiency then it's pointless. I'd def love to see mote prop development but this just isn't the route. On another note, I'm waiting patiently for your 1604 motor testing!

[@RecursionLabs]

As am I since I always do at least one new build in the spring, and I want to try something different. It'll be coming.

[@filipf.5797]

Well I see there a big potential that injection molded and well optimized toroidal prop can actually beat traditional props.

[@colubrinedeucecreative]

OK post commentary; Did you notice they started with tri blade and the one that is published as the final only had 2 blade? Why do you think you could make it work when they clearly couldn't? I had already commented a bunch on this but to sum; You would need to have a cast version to test properly. Though I am not sure if liquid is what they used. But I would guess it was injection molded and the molds made by smoothed 3d prints. #2 there is a lot of calculations that need done. I would have guessed from the into you would know this, but straight blade prop science has over a hundred years of R&D as well as wing geometery efficiency and quietning down pops have always been a huge priority to the military. If you look at the osprey, you will see as far as it has come, and that thing is insanely loud. The airflow over the whole of the wing needs to be known. The thickness of each bit of the prop needs to be controlled as it effects the other side and the speed and driection of the wind flow. These are just hints at it all, but the idea being is if you want to start somewhere start at the 2 blade, and try your best to mimic what you can see in those final pics and go from there, no reason to retread, especially if you aren't going to be evolving the blades, weight, size, just so much needs to be done. It is rather ambitious but a great time for it considering it is viral.

[@mnswamp]

Thanks for the great work! A couple of musings: if this were scaled up, using a larger motor and prop diameter, would it make the inconsistencies in airflow caused by 3D printing less important, and the prop weight be non-linear (larger being perhaps relatively lighter)?

[@erikvf7]

Great test! I think if they are produced with same materials as the normal props they will probably perform much better. But I really don't think they would replace the normal ones. At least for drones

[@AirKhanFPV]

PLA+ is also a good material, its something between PLA and PETG its softer than PLA but stiffer than PETG!

[@NickRO19]

As always, funny and informative thx 👍

[@Rex_Starborne]

The real appeal for these propellers is being quiet, not efficiency. Think of "static pressure" computer fans. You need at least six blades for these toroidal propellers, maybe even twelve or eighteen! Try it with more blades and experiment with the blade angle. I'd love to see those results!

[@googleyoutubechannel8554]

Why did you try the 3 blade, instead of the 2? (which is the one that, in the paper... worked...) Of all vids of tubers furiously copying some other rando tuber fusion 3d stls and then rushing to shoddily print, 'test', and slam together genious toridial 'hot takes' ... this video is well... one of them.

[@mjodr]

I love this guy's other videos and the data on those is greats. But yes, I agree, everyone needed to get their hot take in real quick before the trend died.

[@PabloDeBiasi]

IMHO you can't print roughly a random design without ANY calculation and expect it to behave near the MIT best ones. For the marine counterpart there have been TEN YEARS of development and they outperform by a good margin every traditional marine prop. We must wait for properly designed, tested and manufactured ones.

[@etherealicer]

MIT filed their patent in 2017, so that is SIX YEARS. And they didn't give us any data. They even muted the mic when showing their own design (and if the short flight is any indication, then their drown with toroidal propellers is very wobbly), never gave any data (rpm, thrust etc).

[@wolfpack44rpv]

There is an expired U.S. Patent 6,736,600 "Rotor with Split Blade" to Rudolf Bannasch that looks similar to the MIT toroidal propeller. Please see Figure 7 of U.S. Patent 6,736,600. I have no idea of Mr. Bannasch's propeller has good performance or not, but it would be very interesting to see a comparison between MIT's propeller and Mr. Bannasch's propeller, especially since U.S. Patent 6,736,600 expired in 2020!

[@RecursionLabs]

Very interesting. Your right that an image provided in the patient filing does look like the 2 blade design. i.imgur.com/0gQ8vN9.png

[@jahnkeanater]

@@RecursionLabs The MIT patent also steals an image from Richard Wethern US4445817 from 1984.

[@ellisvener5337]

Thanks!

[@Crytoma]

Typical MIT press release with big claims where in actuality it is more reusing old designs and stamping a big patent on them...

[@colubrinedeucecreative]

11 seconds in and already 3 puns, this is going to be buzz worthy I can tail

[@Mrpurple75]

Thank you

[@Ithirahad]

Interesting how much the material affects it. With something this finnicky, there's probably a ton of micro- and macro-optimization to be made that might bridge the gap (or better) with the traditional props, and chances are there's a "third option" that beats out all of this stuff.

[@Captain5ir1oin]

Great video, thank you. Would it be a fair assumption that the inherent texture/roughness of a 3D printed propeller significantly impacts the performance compared to a more "finished" smooth commercially made propeller...especially because the thrust surfaces are doubled compared that of standard propellers, thereby doubling the drag impact coming from unsmoothed toroidal surfaces? Doesn't seem like a true apples-to-apples comparison.

[@brezovprut4431]

You should also try Prusament PC Blend Carbon Fiber. It might be great choice for both 3D printed props and sub 4" frames. Its tough, wear, UV and heat resistant up to 120C, easy to print (doesn't warp even without enclosure but it only needs hardened nozzle). PS. regular PC blend is not breakable as CF one + you might even consider Tough SLA UV resin 3D printed toroidal props (eg. Siraya Tech Blu resin)

[@mjodr]

That sounds like an excellent material choice. 👍

[@TheVexinator]

Thanks for this, it would be easier to follow if you kept consistent colors assigned to each setup though.

[@RecursionLabs]

Agreed. I usually try to, but in this case I added stuff after doing all the analytics/charts, so it was this or having to redo all that work.

[@raztaz826]

I'd like to see how they compare with a ducted prop of the same blade size, and a prop with an airfoil shaped ring connecting the tips (Search for images of "ripcord flying toy")

[@tasa4904]

If anything, I think the design can still be optimized since you're working with toroidal propellers designed according to an image without any attempts to optimize things like pitch and shape. All optimization attempts right now are to keep them from breaking apart mid-flight. I wonder if you're actually supposed to shrink the propellers to get equivalent performance since I noticed that they spin slower and take more power when they're the size of the comparison props. Maybe if you shrank them by 20%, they'd be lighter and spin just as fast as regular props? Then you'd get to see if they give a more competitive performance.

[@mjodr]

But, if you shrink them then the thrust goes down. Since they already produce less thrust than the commercial props you are going backwards. But also, as an example: 4" props make my quad faster than 3.5" props even though the RPM is lower because my motor isn't big enough to swing them. It's all an interesting physics experiment.

[@tasa4904]

​@@mjodr The thrust goes down if you keep the rpm the same as its larger cousin. But when they're smaller, they're lighter and the motor can spin them faster offsetting the thrust lost.

[@mjodr]

@@tasa4904 I don't think there is a linear relationship there. I don't know why, and I don't know the math, but that's how it seems to play out. Also, a lot of times you are bumping into mach 1 at the tip with the high performance machines we build. You can't just strap on 1" props on a 5" frame and spin them like 400,000 RPM to produce the same thrust.

[@tasa4904]

@@mjodr You're right, it's not linear. But it's the motor that dictates these curves. And when a certain propeller is spinning slower than its peers but the motor hasn't changed, that suggests that it feels larger and heavier to that motor. If I had to break it down into laymen's terms...it's like a monster truck raced against a ferrari on a drag strip...and lost. Then you're taking the result and arguing high fuel consumption (power usage) and lower speed (less thrust) when half the problem really is the massive wheels.

[@odinata]

Have you ever wondered why small drone props are so glassy smooth. How smooth are your printed props?

[@deformemvita]

Thank you for actually providing data. Too many dipshits are just mad that MIT filed a patent before they finished their research, and ascribed some idiotic crackpot conspiracy about "defrauding investors" when it's obviously nothing more than how most researchers have to beg for grant money. I'm hopeful that further development with the toroidal design will provide props that are quieter and more efficient, but even if it's not meant to be; I'm happy that people are trying to push the technology forward.

[@witimez9884]

Maybe you can try with a toroidal prop that has a much smoother surface and less kv on the static station. It can be much more efficient at the lower thrust.

[@Alienami]

Another video I saw on this showed the MIT ones are more like a mobius strip in the shape of an infinity symbol, not this triple prop biohazard design. I've also seen someone print and use the tri blade one on a small drone to stunning results, unless it was really good CGI. 🤔 There is a similar prop developed for boats as well.

[@etherealicer]

The props for boats are from Sharrow, they work and they can be bought. MIT even references them in their patent application, which they filed in 2017. So, since then they brought us a non-informative graph in a data-less paper and a scam video that would make kickstarter proud.

[@RebootLoop]

Here's the TL;DR for the video: "We don't have MIT's actual design, and we're not sure what the testing criteria was. So we made up our own design and testing criteria."

[@markhuebner7580]

Nice graphs and pictures, not as many numbers as I would have liked. Weights, mass distributions pitch& change across radius, a 3-D model of the props, stiffness numbers for the two filament materials. I guess MIT isn't giving those out either.

[@TorontoFPV]

lol Nice I wanted to get in on this but figured they'd be crap anyways. Too heavy! Very interesting video great stuff!

[@hifinsword]

Based on your testing the MIT design seems to fail at being better. But if the roughness of the 3D printed model could be sanded down, there may be a huge difference. Or compare the MIT version to a similarly rough surface standard prop that is 3D printed?

[@Lolerburger]

Great technique on the analysis, but why in the world would you compare a 3D printed prop to a injection molded one of a totally different material? That's the confounding variable that invalidates this data. Gotta 3D print both or neither.

[@russellzauner]

This is a way bigger deal (at least right now) for watercraft than air. The toroidal design removes nearly all cavitation from edges, making it more efficient and quieter as well as removing the number one wear item on props - steam damage. Theoretically, an optimized design could last the lifespan of a vessel, barring external damage input. This isn't as important to people with small props but vessels like cargo and cruise ships are extremely costly and sometimes have to even be drydocked, which causes a lot of stress on a ship that scales non-linearly with size/mass; there is an actual industry segment that focuses solely on repair products/methods for cavitation damage on props to try and extend their serviceable life. This is a big deal for submarines too - in the quiet sense. The toroidal prop designs make a different disturbance and almost none of the noise, obviously advantages for vessels that want to be stealthy. One thing I think is a fault with most enthusiasts trying to reproduce results is that nobody is using smoothing on their 3D prints. Flying is all about wing surface behavior and influence, so why is nobody using the highly available multiple methods for smoothing a laminar 3D print? Even spraying it with some sort of clear coat would be better than nothing, but honestly now it occurs to me that the rough surface would be great for testing coatings on - maybe using that ceramic nanocoat stuff for cars on the rotor would not only smooth out the ridges but make it slipperier in air than plastic (that's a "for instance", there are many ways this can be applied).

[@mr.nikopol]

What if you printed the toroidal propellers in resin instead? the smoother surface could increase efficiency.

[@33rdframe]

I am interested in what you think of my video on this... so far everything you have tested proves my theories correct

[@RecursionLabs]

Took a look earlier this morning. I'm trying to be open and objective, but your points are valid. What I did not like is that they were using thrust stands made by the same company as mine (shown in the intro) with all the same capabilities. This means they definitely have data they could have published if it would have helped sell the concept, but chose not to and instead only made claims about eliminating a specific frequency of noise....

[@33rdframe]

@@RecursionLabs there have been a lot of claims that they withheld the data due to their patent. However, the patent is so broad it kills even modifications. And that explanation doesn't answer why they would boost the standard FPV drone, but then intentionally mute the toroidal one ... Is it that when on the test bench they can spin it at lower rpms to achieve low sound? Whereas when on the drone the thrust needed to take off is consistent between props

[@RecursionLabs]

@@33rdframe That wouldn't make sense since the entire point of a patent is so you can release information but be protected. Even if it didn't, it's not like that information would be useful outside of demonstrating capabilities.

[@tokiWren]

I wonder if these propellers will perform better if you sand/polish them. The 3d printed parts have a lot more ridges, which I think may decrease the effectiveness of the propeller because of drag or vortices or . something .

[@sceptic33]

these toroidal props aren't new, they've been around on boats for a few years at least... higher efficiency than old school prop shape apparently... pretty expensive to buy though

[@american7169]

Quadmovr did a prop swap, tor vs octo. The octo was way quieter and better power.

[@bariman223]

1:00 Did you 3d print the other propellers that you're comparing this propeller to? Materials used does matter after all. EDIT: OK, you recognize the issue. However, I'm surprised you bothered to do experiment without setting the materials and production method as a control.

[@wtbwtb8133]

What about the noise? Since one of the major claims was "Quiet".

[@rafaelgonzalezmorales1824]

3D print the standard prop and retest

[@francisdaoust5862]

I have done it with a custom design and it was efficient as long as the design is tuned. But for the trouble it get you, it is a waste of time.

[@francisdaoust5862]

Those results was exactly what I was beliving. Until we design a ultra ligth propeller with a improved design, I m not a beliver. I honestly wish that It can be a improvement but motor like ligth propellers. I offer my help in a facebook group to try some design, if there is some interest, I may try some also

[@Pintosonic]

Toroidal props are the biggest fad to hit FPV since the angled motor bases that were supposed to make our quads more aerodynamic in forward flight but ended up just making our quads fly like crap. Now these props are not significantly quieter than regular props, their sound is lower pitched but low frequencies travel longer distances so what's the point? But with reduced efficiency flight time will decrease so people annoyed by the noise will be happier I guess...

[@mikenomatter]

it would be correct to print out a regular propeller and compare with it

[@Skinnamarink.]

Blades like this have been around since i was a kid. they work for water. not so well with air.... Its crazy how many people try to design something based on a totally unrelated thing..im never surprised when it doesnt work lol. air dynamics and fluid dynamics are a bit different lol

[@JeromeDemers]

amazing but like you said the most important part of toroidal props is the sound they make and you didn't add that to the graph. And these are randomly design props

[@DronoTron]

I hope hqprops or other manufacturer produce proper polycarbonate toroidal propoellers to test.

[@AugmentedPixel]

Seems like the results would be better with a resin printed propeller so there are no surface defects or layer ridges I’m printing mine now on my resin printer with strong Engeneering resin

[@marielizysurourcq]

" starting with THRUSSST ! " 😦😤

[@adamseal]

Hi just wanted to ask are you going to test the tmotor 1604 motor?

[@starraider25]

Well these new props aren't that efficient, but I'd like to see if they make the drone more stable in the wind. Then they'd be worth it.

[@humbleopinion2722]

What about using these for water propulsion?

[@autonoob]

You can use 3 dimensions to avoid the intersection of the blades. I think that harsh join isn’t going to do anything positive to the aerodynamics.

[@markhuebner7580]

The mass and diameters are not mentioned?

[@hanelyp1]

Looking at those propellers, they invert the root to tip twist conventional propellers use for good efficiency. No wonder they perform poorly.

[@2Meerkats]

meh... How about a report on the ZipLine single-blade prop used in Rwanda.

[@AtomicPaperclip]

Has anyone tried to adapt the fans from Fan Showdown for use on drones?

[@q8qatami]

Bi-blade toroidal might be more efferent

[@mjodr]

That's what I would try too. I think, based on the spread out information I saw, that was the best design.

[@b3owu1f]

OK all.. 3d printed props have layer lines.. and staggered steps. Any chance ANY of those not so smooth aspects of 3d printing are affecting this? How about you ALSO print regular props.. and compare those.. lets rule out if the 3d printing layer lines/roughness/materials is the issue at least. If these toroidal props were made smooth like regular props.. how would they compare?

[@peetiegonzalez1845]

I wonder just how bad a "normal" prop would fare if you just knocked up a design in CAD without any aerodynamic calculations or testing, then printed one in low-res PLA without any regard for weight. These experiments are kinda fun but don't really attempt to explore the possibilities. The 2-page paper from MIT has a photo of their props and they look far lighter, thinner, and have thickness optimised along the loop so there's less weight used at the outermost point. They don't look anything like what anyone on KZbin has managed to design so far.

[@mjodr]

Yeah, everyone got a little excited and the 5 minute hot takes show their weaknesses. For the thickness of a typical drone blade it will be very hard to make something optimized in all areas with just FDM and typical nozzle sizes. For example, even just my 2 blade Gemfans, the injection mold is pretty complex. I don't see how I could even come close to copying that shape with FDM.

[@lee8org]

I see only one positive aspect ..if you fly the quad in close proximity of the people ..they might feel safer... Please compare the efficiency with ducting configuration.

[@nickaxworthy1572]

Thank you, it’s a shame they don’t live up to the hype - perhaps unsurprising, with proper CFD analysis and the correct materials and finish, they might come close

[@WikWak]

Hahaha Thankyou for this video

[@JCisHere778]

Using the toroidal prop for a cinewhoop is probably a terrible idea.

[@tehllama42]

T H R U S T

[@davidullman44]

I have no idea if the toroidal prop is any good or not. I do know that your experiments add little to understanding their capability. Building a single (or a few), clearly non-optimized crudely printed prop to compare with one that is finished and optimized is not a fair comparison. Further, based on your own data you are way off the mark for running the props you made. This is evidenced by the sluggish rise in rpm implying that, what could be thrust, is wasted as in-plane drag.

[@MadDragon75]

Just looking at it you can tell... All it is is a duct-style prop.

[@terpsquirter7107]

These props suck not only are 8 blade propellers quieter they produce more thrust and less vibration womp MIT is getting tired handing awards too whoever

[@jacewalton6677]

Your comparing a sharp smooth injection molded blade to a gangly heavy toroidal prop. Do a 3d printed standard prop ba these. Or better yet send a model to this guy youtube.com/@JohnSL He does alot of small injection molds. He may be Interested in making some molds for some toroidal props

[@natalyakeane]

the MIT hype does seem bs. but if you are gonna test these to this extent, please compare them to 3d printed traditional designs. it will likely show similar results. but continuing to show 3d printed un-optimised designs against injection molded optimised designs kinda undercuts any info

[@krautergarten4529]

Please print a traditional prop with ur fdm printer an test it ... will most likely preform even worth than the printed toroidal prop. 🤦‍♂️ The overlap beween people with prop teststands and resin printer seames nonexistent. Why do you even post such a test? Pure kickbait!

[@supyrow]

It proves that it is bs. It's a scam.. a 35 year old scam . It just came back is all.

[@Rayzo45]

wrong toroidal fan manufacturing😑

[@dcolb121]

Lose the background music

[@mjodr]

I agree. It sounds like somebody is talking in the background for some reason, haha. Some weird beat that mimics human voice a bit.

[@JustCallMeChad]

Test it against a 3D printed prop FFS!

[@elyaperestigli2774]

Bro, your torodial props can’t be called props, u desing a fans.. and fans are realy bad in thrust generating, they just move air..

[@henrywells6223]

You guys propeller looks nothing like the mit propeller absolutely nothing like it

[@stevensbox9625]

Yeah, the toroidal design is a scam. Just keep saying THRUST