Toroidal Prop Testing: Is this the future of FPV propellers?!

[@hesher.]

Those scientists at MIT didn't come up with anything, they just added the wrong name to the mobius strip propeller so no one would find other research. I found a publication dated 1996 on the subject of these propellers. You can find them by searching"Propellers And Fans Based On The Moebius Strip" or "Screws, propellers and fans based on the Moebius strip" 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

[@hesher.]

This is just yet another empty hype crap to collect sponsorship money

[@chemistt]

@@hesher. or a very cool trick to annoy people with their stupid and cheap video so the public would actually try and prove them wrong and develop this for them?

[@Chris-hn4lp]

@@hesher. They may have copied the idea from the mobius strip boat propellers, but these propellers do have the potential to be far better than conventional ones. They just need to be perfected first. Look at how much more efficient Sharrow boat propellers are than normal boat propellers.

[@chrisbee5481]

Thanks for summing it up. I was about to write something similar. 6 blade props are more quiet indeed. Also like you said because of motor load, you cant just replace a 3 blade with a 6 blade or toroidal in the same size/diameter, without overloading the motors. You need to go down like an inch.

[@Chris-oj7ro]

@@Chris-hn4lp It is very likely we will not see the same benefits as the Sharrow propellers. Moving through water is much different than moving through air. Specifically the Sharrow propellers prevent water cavitation from forming at the blade tips which drastically reduces propeller efficiency. I'm not an expert but from my understanding there is not a direct equivalent of cavitation for propellers moving through air.

[@STRIKINGFPV]

I'm actually quite surprised that my V3 tri-loop managed to perform as well as it did considering how old it is now. Wish I had more time to explore the topic more, but thank you for doing this really solid testing. I casually theorised a lot on the possibilities and potential of toroidal designs, and your very thorough testing I think has brought us to very similar conclusions. I was never of the thought that toroidals would ever replace standard designs, since an aim for efficiency and more discreet operation is a bit of a clash with acrobatic flying, but I still think maybe the Cinewhoop space could benefit in some ways. Certainly the tri-loop looks less likely to cut us up 😅. If it's not too much to ask, I'd appreciate a tag - also helps me keep track of people who've tested my design as I've been maintaining a playlist on that as well. You might find that interesting, especially one of the videos by MoppelMat where he printed the V3 tri-loop out of Nylon-CF and made props lighter weight than equivalent 5" injection-moulded props he had lying around: kzbin.info/aero/PLYXuRA_sySbwa7FRot80kzEA_j4iqWQ_w Also, Foxeer just posted a teaser on their Facebook of a production injection-moulded bi-loop design which would be worth putting through its paces, I think. Proves that injection moulded the bi-loop is possible, now wondering if they might be able to work-out injection moulding the tri-loop. Exciting times, hehe.

[@chrisbee5481]

I can't find that foxeer post on facebook. Can you confirm it's still there? Any date?

[@chrisbee5481]

Still waiting for foxeer to release.

[@STRIKINGFPV]

@@chrisbee5481 Yeah it's delayed for some reason. I asked and they just said "soon", so I'm wondering what's up. Could be manufacturing, maybe. Or if they've sent out review samples maybe they want a bunch of influencers to post about it at the same time as release? I dunno, completely guessing 😅

[@adrianthrockmorton7557]

It might have been a good test to 3D print the Nazgûl prop so you could see a quantifiable amount of degradation due to printing. You could then somewhat speculate how much more efficient the toroidal props will be once they’re injection molded.

[@justainchoe6141]

I have to say, with all the tests already out there, I’m not sure why Chris missed this detail. It gives it more of a even playing field to test the new tech.

[@Athiril]

The drag might equalise them both though. I think something better is to use body filler on the props and sand them smooth and balance them after

[@alexanderg-p3z]

@@Athiril Or use the acetone-vapour smoothing method.

[@alexanderg-p3z]

Ah, just got to the part where he adress this point

[@EdBruceWRX]

Would a resin 3d printer be better?

[@hesher.]

You should test this 'three' blade moebius strip propellers with 6 blades regular propeller, because this design just doubles number of blades

[@scottmilano2940]

This is important, because the 6 and even 8 blade props are substantially more quiet than even these toroidal props. Quadmovr had a great video showing this when MIT first put out their press release.

[@ct333]

Indeed. HQProp offers 8-Blade Props (in 2.5", 3" and 3.5" I think). They are indeed quieter and also have a similar windy sound.

[@HeroRc]

I think the material of the prop is also really important. You can see printed props bend significantly when they spin. This can reduce their performance. I wonder how would they perform when made of polycarbonate.

[@TheVexinator]

Yeah, the deformation of the prop while spinning was quite evident, especially on the last one (strinkingfpv 3 loop) @6:00. The area inside each loop seems to be expanding (i.e. what would be the "tips" seems to be pulled towards the center as the "wings" of the loop are spread apart).

[@TheCreat]

Polycarbonate can be printed on (generally only advanced) 3D-Printers, but it isn't trivial. They require exceedingly high temperatures for the hotend (~300°C) and relatively high for the bed (100+ °C). Even then, it remains to be seen if they behave differently due to their layer-based construction compared to injection molding, as stresses from high RPM might manifest differently despite them being the same material. Another way would be to print negative molds and construct them from CF+Epoxy or similar, but that again is a very different and extensive process.

[@putteslaintxtbks5166]

They could be cut out of a solid block with a multi axes laser cutter, perhaps.

[@severpop8699]

@@putteslaintxtbks5166 nope, but with a 5 axis mill it can be done

[@severpop8699]

negative, bad layer adhesion on PC, needs rebakiing, that warps a bit the shape, all goes bannanas, best is CF Nylon, or CF PPS for cheap money, for bigger money PEI or PEKK CF.

[@neilfpv]

Logically, I think the 2 loop toroidal prop is equivalent to a 4-bladed prop, 3 loop == 6-bladed, etc

[@ibnfpv]

Its interesting to compare the sound frequencies spectrum Of the props incompare and not only dB as there is more sensitive freq to Human ear than other

[@shALKE]

What happened to your voice? Sound different.

[@kwikam]

he switched to toroidal vocal chords 😂

[@runpuppyfpv5744]

Teeth look whiter too

[@YorkyPoo_UAV]

​@@kwikam you beat me to it

[@skyweaver3199]

It's probably a new microphone. That has a KZbinR setting....

[@alperenozgur]

he went cyborg

[@ZenoMinus]

@ChrisRosser Your analysis are really inghtful, could I propose a few more tests? Would be great to test comparison with toroidal prop and "iFlight F5 propeller like 3D printed" to remove the material out of the equation In the same way would be great to test Zipline props, what borthers me most is the noise that quadcopeters produce, I would happily sacrifice a little of performance to have a quieter one

[@michealkinney6205]

I think to do an apples to apples comparison, you should CAD up the traditional blade and print it on an SLA printer (as close to the same process and finish) and see how much the performance diminishes and compare that. If you see more than a 10% drop in efficiency on either thrust, power or both, there's definitely something here. Best!

[@k4x4map46]

A set for your (my) experimental--test bed AOS7 would be perfect!!

[@ManjaroBlack]

Compare the StrikingFPV triloop to a 6 blade prop.

[@olorf]

Amateur designed 3d printed props aren’t really a valid comparison. Now what Foxeer are releasing next week would be more exciting to see a comparison of.

[@sunoncream1118]

you alll overloading motor with those loop... XD cuz one loop is already a 2 blade, and so 2loop is already a 4 blade prop...

[@baggszilla]

Thanks Chris!

[@kaptkrunchfpv]

Welp, that seals the deal for me, for the near future anyway. Thanks!

[@KiloWattPlays]

Even if they were better. we'd still have to fly off our old stock of props😜

[@GeorgeTsiros]

yeah we would need to see thrust-vs-noise curves to make a judgement on noise levels though

[@hazzahfpv6675]

Damn, bad timing with the Foxeer props coming soon

[@Stefan_73]

Interesting data. What happens if the airflow is not perpendicular?

[@gunnarfernqvist4896]

I think the toroidal props has more of a future in water appliances than in the air. Boats for example are suffering a lot more of vorticies and cavitation than an airplane due whipping around the much more dense water than in air.

[@rgross989]

I am curious of performance and durability. Are they going to be louder when damaged? Are they going to still be mostly functioning at close to normal performance when damaged? Are they going to be flyable when damaged?

[@deroskar]

Durability is a good point. But i think those would be more for Longrange + Autopilot applications than for freestyle

[@Siamect]

I think it's pretty obvious that loop blades can never be as efficient as single blades. The ones we see today are also having completely wrong angle close to the tip. I'm sure you can find traditional props with vortex management optimized for noise reduction but if you optimize for noise reduction you will get less efficiency than if you optimize for efficiency which is pretty obvious...😆 So my take on the concept of torodial props ... It's just a hype. The current patent I think was from 2017 and they still haven't been able to show any better performance except possibly noise but even that I think is probably better using traditional blades optimized for noise reduction.

[@cleanroomwizard2356]

Really excellent examination of the propellers for the key properties of interest! Perhaps I missed it, but was there a comparison of the noise level for the same thrust/power, or was it only at the same speed? I imagine it would be more important to consider the noise level vs. the amount of thrust you can achieve ultimately if you are optimizing for that. I guess a frequency analysis of the sounds could also help in determining why they seem quieter/less annoying.

[@alistairclark6814]

Funny what doubling the surface area of a propeller does. I would like to see it's efficiency compared to conventional props of the same surface area.

[@chrismcgowan3520]

Could you look at doing these tests with a counterweigh prop ie the propeller is only on one side and a counterweight is on the other thus would remove the proppelor wake issues and also make it more comparable to a two blade proppelor

[@parkersdadtyler]

Thanks for posting this...fascinating. One thing I think would help you understand your perception of the dB SPL measurements. You are on the right track...but Human ears are more sensitive to 1k Hz and higher frequencies. In audiology we measure in dB HL (hearing level) not SPL (Sound pressure level) when measuring people's ability to hear different frequencies. We record the measurements in HL due to a concept called audiometric zero. Significantly more SPL is needed in the low frequencies for the average human to even hear the sound. So in dB HL we are actually experiencing lower sound intensity in the lowere pitches. This can be verified by googling "equal loundness curves in dB SPL) which will show the amounts of pressures needed for sounds to be audible in humans. I hope this helps....thanks again.

[@ah4quadssake885]

Im wondering when they decide a single blade with a weighted balance is the best prop for efficiency. Stiffness of the prop is also important like glass fibre APC props or carbon fibre/wooden props. The plastic props have the toughness for crashing but deform under load. 5 inch racing/freestlye quads, plastic 3 blade is best. APC props for model aeroplanes or mejzelik carbon if you can afford them. Torroidal props have their place but wont re-invent the wheel

[@Jacksparrow13963]

Please make a video about *best long range fpv motor* and please test this motor with 2 blade 8 inch propeller ..... We want to see the most efficient motor and most efficient propeller for long range fpv Drone ......🗿🗿🗿😭😭💎

[@The_Privateer]

When you say "futuristic" and "totally new", do you realize this was patented in 2017? Not really so new and futuristic. This prop is a scam.

[@dronehater_fpv9474]

Shouldn't you print a traditional design prop using the same technique as the toroidal props being tested? I'm not 100% convinced the differences in manufacturing process and materials is negligible.

[@jeffersonblackmon]

The archaic way math\geometry is taught globally has us 5,000 years behind what the Ancient Africans already knew. If Vortex Math was taught in high school many new inventions would be produced that would revolutionize every industry. It makes one think.

[@bergdada7311]

And why not try the usual three-bladed propeller with the blades united by a ring. Not rotating inside, but a one-piece design and work with the corners of the ring, the upper edge is wider than the bottom and vice versa.

[@christopherconkright1317]

would the injected mold make a weight difference if you had them made the materials are not the same

[@scottmclaughlin1410]

I would like to see what effect it would have to add a ring to the outer edge of a 5 or 6 blade prop. It should similarly reduce the tip vortices and add strength to the props

[@breakflight]

Thanks. Test the new Foxeer toroidal props.

[@ChrisRosser]

Will do

[@Quick-Flash]

Just an FYI all the props he tested were made by non aerospace engineers who just made something that looked right. You honestly can't expect someone with no background in such a complicated field to make something better than what we currently have. Now seeing a toroidal prop made by someone with the proper engineering background would be quite interesting. However, even seeing that these props can bet a bit close to our current props shows that it will likely end up being something worth using.

[@thirtythreeeyes8624]

This is what I've been thinking since this whole toroidal prop craze started.

[@13374me]

@@thirtythreeeyes8624 not to mention 2 dB is almost twice as quiet, not much of a difference my a**, it's a freaking logarithmic scale

[@sulev111]

Planes have curved tip wings. Why don't drones use that?

[@simiken1234]

Great video! A couple notes: It would be very interesting to see the noise power over frequency. Also SLA still has tiny layers which still could or could not impact efficiency and noise.

[@catfishpoptart1997]

It is worth noting that a 3 dB decrease is half as loud, so in theory the three blade Willow toroidal prop is half as loud as the two blade Willow. When you were testing the props did you notice a significant difference in volume or was the perceived difference less due to the different sound profiles?

[@13374me]

it should be a significant difference in volume, saying 2-3 dB different "isn't much" is completely ignoring that it's a logarithmic scale, I don't know if he's oblivious to that or just being facetious

[@shadowcult464]

I wonder if there is a way to have variable pitch.

[@Red-jr9qm]

Personally, I don't see traditional props going away for the one simple reason that is ease of manufacturing. Even if there was a marginal performance increase, it would be offset by the additional cost to retool production lines. This would be particularly true with upscaled applications such as aircraft parts, where factories would have to be retrofitted and the new propeller design would have to be FAA approved, which are both incredibly expensive endeavors.

[@aliendroneservices6621]

With small drones, there is also foldability. Current small drones use foldable prop blades for compact storage.

[@H1DD]

Nice video. Thx. I wonder why the hell no one printed traditional props together with those toroidal ones?! Seems like this way we would compare "apples to apples" cuz manufacturing process is the same.

[@STRIKINGFPV]

I did actually, but not scientific just a test hover. Funnily, my printed hex-blade drew more amps than my printed tri-loop, but it was just a hover test so no idea what the performance would be like for the rest of the thrust range.

[@zer001]

can we do winglet thingson the "normal" prop?

[@rabbitambulance]

Thanks for cutting through the hype, Chris. It's interesting to have seen GemFan's comment on JB's livestream the other day. The message was something along the lines of them wanting to move forward, but not necessarily knowing how to work out the credit / attribution to the MIT team. The fact that there is very little technical information available from that team, and that folks have to reverse engineer the dimensions and parameters is frustrating, to say the least.

[@Quick-Flash]

Foxeer will be selling toroidal props later next week. I'm guessing they just bypassed MIT entirely to get them made.

[@jlarson42]

Very interesting and informative video. Well done demo and explanation. The other issues that are top priorities to fpv pilots. Cost, I'd wager these will cost more. And durability, good props I can just bend back and keep on ripping. I have a feeling these toroidal props won't be so forgiving. Happy flying everyone. 🤓

[@Inertia888]

Maybe different use cases? For the toroidal props, I would be using them in situations where I want to fly close to people, and also introduce as little 'annoying' noise as possible. Where, when I'm just rippin', and really pushing my limits as a pilot, I don't care as much about the noise, I am all about power and efficiency.

[@KiloWattPlays]

There's also less corners to get stuck behind the propellor, everything is rounded off. but yeah, they probably wont bend back with the same characteristics

[@jlarson42]

@@Inertia888 or they may act like cheese graters instead of knives. 🧀😋

[@modquad18]

Counterbalanced single blades are the future 🤖

[@JohnDoe-bd9cx]

I'm guessing the material used to make the prop would have a wide range of differentiates.

[@zer001]

You are awesome!

[@knoopx]

an spectrogram comparison would give a better idea of whats going on

[@coilockerfpv]

I'd like to know how they sound within a duct on a Cinewhoop setup 🤔

[@coilockerfpv]

Also, have you seen the new video from @TheActionLab about a different style of silent propellers? That would be an interesting collab

[@theartofflying3108]

It is neither of those it is a hype!

[@testpilotian3188]

They won’t be used for freestyle, they’ll never survive scraggle, I use Ethix P&B props and more than once I’ve flown back on only two remaining of three bladed props, with these new props they have so much surface area that knocking off one edge will put them so far off balance that you’ll have to do the walk of shame, they’ll be best for long range stuff where they won’t be beaten against a tree every 2 minutes.

[@yupiterino]

I think it is better to compare props with the same blade surface area. I.e. compare a 2 loops prop with a 4 blade traditional prop, what do think about this?

[@SueMyChin]

Thanks for the info on these. I'd have loved to see how the do on a safety point of view. Our traditional props are dangerous around skin but I feel like these wouldn't draw blood if they made contact. Would be interested in a short video on, maybe see how each do vs a tomato or banana?

[@wubforceone]

i garuntee 100 percent they will draw blood. i dont think your realizing how powerful fpv motors are and how ridiculously fast they spin. may be slightly less damaging yes. but i garuntee it will still cut your finger to the bone in the right moment.

[@wubforceone]

4s 2500kv. thats 2500rpm per volt. max voltage of 16.8v thats 42,000 rpm.

[@SueMyChin]

@@wubforceone Yeh, but I still want to see for myself if it does...

[@wubforceone]

6 bladed props are just as quiet if not more...

[@BrainDeadEngineering]

Oh it is a revaluation . Its coming! I talked to HQ-P and they said they are working feverishly on it but making the injection molding is very hard . It has to be a multi peace tool. Here is a prelude to the dream video. kzbin.info/www/bejne/rpekXpqwps2ejtk

[@mrbmp09]

This shows some people will sell a turd for a profit, we're looking at you Mr. Steele.

[@ChrisParayno]

It makes sense that the thrust from the cordial props would be less efficient because there is more surface area, therefore more drag.

[@elcampeadorr5043]

Hi how You measure thrust?

[@papamidnightfpv]

I just saw a video on "Zipline drone silent propeller" they use staggered propellers that look like a 'V' with a little counterbalance. He goes into the science about why the propeller make noise in lower frequencies and it's quite. Toroid propellers are neat but these other props are really weird.

[@benjaming9835]

I have tried a number of different toroidal props with a 3" quad, but have a lot of oscillation issues that I can't over come. Which I think is due to the props larger mass, the little 1404 motors just couldn't accelerate the toroidal props as needed. Could there be size limits?

[@13374me]

It's more likely to be a balancing issue with the printing rather than the design itself

[@Pukkaras]

it would be fun to look at a comparison of the same characteristics if use 2-blade props with winglets as classic, and not a three-blade iflight. The addition of winglets makes it sound similar to toroids, precisely because winglets are used to reduce turbulence at the tip due to the right of the flow at the transition of high and low pressure areas. Also, in terms of efficiency, a 2-bladed one would overtake even more toroidal ones. 4, 6 bladed propeller cannot be effective. Much easier to add winglets to 2blades if you need efficiency. Never propellers with the same pitch and diameter of the propeller if addition of x2 blades will be more effective only in reducing stall at the tips. Winglets decide this.

[@DMPB-fi2ir]

actually toroidal are not new there are patents almost a go back a century, the first aircraft toroid propeller was patented in the 1930. and the actually are in us on some us drones for military., tip on a prop is the same idea on wing tips and in part the bases behind winglets as seen on tips now with the curved and angles tip to cut down turbulence and noise. the origins of this actually goes back to ship prop in the 1890. I did work for company for design manufacturing and these were built and tested for military use back in the 1970's so people need to do their homework MiT was not the first and they are not new just being approached different with 3d printing

[@brazenclips]

Your conclusions don’t seem to align with the research papers. Could it be that using injection molded props versus 3D printed is the main culprit? I think so.

[@8anos8anos]

Let me Enlighten us guys as for the sound perspective. The dbs that we get from a db meter is not corresponding all times to how loud a human ear will experience it. Let me explain why: Human hearing is not flat n has emphasis to mid range while decreasing n getting unnoticeable (most of times) close to our limits, below 20Hz and above 20Khz. In simple words we hear louder mid FRs. DB Meters measure the Peak n not the overall summing. On top of that DB meters has 3 different types of measurements, called weightings. A, C ,Z that effects the results. Mics also varies in sensitivity through the FR band. A quality balanced DB meter will have more accurate measurements. Let's also consider on scenarios like propellers that noise can be spreaded to different directions (depending the design) versus for ex. an exhaust that has only one way out, is prefered in my opinion to have multiple measurements like from Front Side n Rear. Last but important factor when recording is to isolate from any maybe reflecting sound that will increase or decrease some frs n disturb the rec. Last, 3db difference is quite noticeable n can be an important factor when u need to be less disturbing or even undercover. As my quick measures from those recs, the FR Hertz Peaks are: (k=khz=kilohertz) 1. 1k 2k 5k 2. 500Hz 1k 5k 3. 50Hz 170Hz 1k 4. 150Hz 2.5k 5. 50Hz 180Hz 800Hz 2.5K V3 3Loop sound preference for me as i prefer Low FRs , is less peaky n more wide spreaded

[@andrewmcewan8081]

toroidal props have been in use on boats for a while

[@aliendroneservices6621]

Sharrow.

[@Inertia888]

My AOS Cine35 is absolutely SCREAMING loud. I hope these toroidal props find their way to the consumer, from an injection molded form. Would really love to be able to fly my Cine35, without waking the devil.

[@wolframzirngibl1147]

Let me put it this way. Your comparison is a true pragmatic one. Just measurements. But there is a theoretic way of judging these things. Just try to unwrap shown designs in order to change the circling movement through air to a linear one. All of a sudden you notice those critical blade joints near the prop hub except for the 2-"blade"-toroidal designs. They cannot be efficient. They are a pure source for induced and from drag. No single one aerodynamicist would ever propose such a nightmare. Further, every single "blade" turns out to be a biplane's half wing. Guess why biplanes made it to the dustbin of aviation? As a result, a true improvement of any toroidal (bi-)wing must create axial space for the two wings of a loop and the tip joint of the two blades. An example of a truly efficient toroidal prop design gives an impression, what may create an advantage: kzbin.info/www/bejne/oWHcq3WKidaZsNU The designs shown will never succeed. BTW: MIT has shown to output crap in some cases before. With witricity amongst the most bizarre nonsense to my knowledge. Don't believe just because of a MIT label.

[@MarkRichardsMokey]

Thank you, this is very good information. I would love to see an audio spectrogram or FFT for the sound produced by the toroidal vs traditional props. Also, I agree that the efficiency of these new designs will improve fairly quickly.

[@chq6929]

Fact is, toroidal props equals(if not worse) prop that has doubled blade counted, thus should also be compared to doubled blade count props. e.g. Tri toroidal props should be compared to 6-blade normal prop, not 3-blade normal prop. That's why toroidal props tends to be lower on frequency and also lower on efficiency - just like props with doubled blade has lower rpm and less efficiency when hovering.

[@4.094]

I think noise is the most important thing for me. But I heard a fanless drone is call ion something i forgot the actual name.

[@juanmohedano2216]

It's getting kind of clear that toroidal will be used for cinewhoops, places where you dont want to disturb anybody and maybe for bigger drones since 7' and forward apparently make tons of noise; while standard will still be used for freestyle, racing and probably tiny whoops for the weight difference. Great informative video

[@kadmow]

- also for "safe" props - if the tops are very circular - as has been done with outboard motor props - it could reduce (perception too) potential for harm.

[@sirsmeal3192]

I am curious as to strike applications in Ukraine. They brag about how maneuverable the FPVs are, but I suspect it is not needed. A toroidal prop being quieter may give them an offset ability to get closer before detection.

[@ariafpv]

Why do we even care about noise in FPV. We're always looking for flight performance over anything else. No matter what size an fpv quad is, they always need to fly better and with more power than let's say a mavic or delivery drone. And if someone really wants to develop a quiter prop, they should be working on heavy cinewhoops and not 5" freestyle props

[@userunknown2771]

Ukraine is taking notes

[@rscott2247]

There was a testing of Toroidal propellers on out boards for 25 ft boats there abouts. The area where the Toroidal propellers excelled over conventional 3 blade propellers in terms of speed, fuel efficiency, noise was between a 3000- 4500 RPM range.

[@jawz101_fpv7]

I don't understand how MIT can patent toroidal propellers. After googling about it the other day, Sharrow Marine propellers are basically the same thing & have been around since 2012.

[@magicmike1122]

All I know about Math is nothing is free. Loudest one is most efficient, and quietest one is least efficient.

[@willowehrich6207]

I'm just finding this now. It was neat seeing some of my designs get tested and that they worked as well as they did. When I was designing these I was just learning cad and used these as a challenge to improve my skills. I didn't use any special airfoils or anything. Just eyeballing these and slowly improving them. At the time I didn't even have a 3d printer so I had to rely on others to print and test them for feedback. Most of my designs were designed for easy FDM 3d printing so the bottom of the blades were flat to adhere to the print bed. I've since learned a lot more about prop design so it'd be neat to do some new designs meant for SLA printing.

[@WyldWolfDragon]

7:50 Brooo you're amazing, will definitely be checking out your sit, appreciate your video comprehension and website

[@ignasanchezl]

Yo know, I've had people complain about my 3 inch quad noise, I think I would consider them, as I'm not yet a high performance flyer.

[@aaron6516]

I was waiting to see when you were going to pull this thing apart. More practical applications I would guess would be for commercial jobs but like you said need to get some more refinements, and it would be nice if MIT would share...

[@denismorgan9742]

These toroidal propellers can be made by injection moulding, first you would need to smooth off the toroidal the best you can before making a cast. The next part would be choosing the right plastic for your needs whether it would be light in weight or durability or both. Obviously the surface of the blades that was injection moulded would give a much different result on toroidal than a rough 3d printing, weight and type of plastic would also have some bearing on the results. As it is there is too many variables between normal blades and toroidal to make for a fair test, as you mentioned it is literally 3d printing against injection moulding.

[@keylitho]

Seems pretty clear they won't be replacing anyone's freestyle props any time soon..

[@Relou4e]

The name toroidal is misleading and started with the boat prop. Looking at the boat prop you can see the real design philosophy: it is a tandem wing with the benefits of winglets, the leading wing (sort of extra big leading edge flap) has a downward winglet which is joined with the upward winglet from the other wing. This accelerates the medium (here air) twice and because the prop circle area is limited it gives more thrust. ;-)

[@josephrsalexander4589]

What is the traditional refinement process for an FPV prop? Is it (1) computer simulation or (2) making 50 versions with a thrust stand?

[@actionjack84]

How perfectly 2023. We can measure no improvements from our "innovation". Ureaka! Toroidal props for all!

[@SixTough]

You are brilliant, thank you for sharing this. I'm sure you already know but lower frequencies get attenuated in air more than high. Would have been interesting to see the spectrum from the mic.

[@rasmus80g]

Now we just awaiting propellers with wingtip's =) .... as a soaring pilot i have learnt wingtips is only good for one thing. Reducing the wingspan. Same length just flatten out is better.... however on a propeller the end is spinning faster so might be slightly different here....

[@severpop8699]

kzbin.info/www/bejne/sGabg4KIeLqHl9E has an interesting isight with two baldes prop at 30 degress from eachother and offset on the same axis by (my guess) one blade chord, all counterballanced on the other sde on a short arm with a weigth, and that makes it even more quiet plus manatians the airpush of a two blades, highly effcient. What if you take the two (double) baldes thoroidal system, eliminate one blade (pair) and replace it with a weight, ballance it with some metal inserts and eventuall screws and measure it against the others?

[@JoeSmith-cy9wj]

I'm not into drones or RC , but right off the top I'm going to guess the extra mass of a toroidal prop will significantly degrade performance of aerobatics because of the gyroscopic effects, and throttle response.

[@rasmus80g]

Missing a normal 4blade propp as reference. The "2 bladed torodial" is basically a 4 bladed propp. (Or even a normal 2 bladed propp...) its not really apples to apples here...

[@GC-sg9jv]

A ducted propeller addresses tip losses and a ring propeller (and more commonly as a fan) has effectively zero tip clearance. These blades may also have forward and backward curving blade sweeps. These designs have similar advantages and limitations as a toroidal prop.

[@Oderwat]

Hey Chris, I do not know if you saw this video but it features very quiet, actually used props. I wonder if those could make it onto a fpv drone: kzbin.info/www/bejne/eoC6dYF4qp53obc

[@billmcdonald4335]

In a word: no. These have limited use for small aircraft. Just because the marine version actually does work as good or better than a standard screw doesn't mean the concept translates to drone use. The fluids are vastly different, as is the rpm; the scale involved must be considered, as well. The initial presentation looked more like a student's assignment paper than an actual results report, this makes the whole thing suss, kinda like room-temperature fusion in a beaker.

[@borysnijinski331]

Funny that you state 1 or 2 dB is not much but a couple grams of weight is significant. 2dB difference is a lot. A couple grams is not.

[@DoctorMandible]

$50 "reference" mic would've helped a lot. It would show you exactly the frequencies and the decibels.

[@bobasher2046]

Currently all commercial aircraft manufacturers attempt to remove the vortex by fitting winglets, as a props profile is basically the same as an aircraft wing surely the same could be tried on props thus adding less weight.

[@nathanp3366]

Why would it matter if you use mechanical power over electrical power? If you are using the same motor for each, it seems like it wouldn’t make any difference, at least when looking at the data comparatively which is what it seems like you were doing with that chart.

[@BosonCollider]

It'd be interesting to also test the durability of these props. It looks like they would turn prop strikes into glancing blows, but be more likely to get tangled up if you crash into a tree or bush. They look like a good alternative to prop guards for tiny whoops

[@hipphipphurra77]

It would be interesting to compare with a traditional prop featuring a circular rim.