There is one more aspect: At the moment, toroidal props are much more prone to damage. And if toroidal props get damaged, it influences their functionality much more.
Toroidal props were not invented in 2017. There's published research on prop configs w/ joined tips (toroid, box, non-planar, etc.) going back to at least the 1960s.
Chris, i’ve been watching your content for about three years, honestly it’s about time I tell you what a great resource you are and spread a little appreciation your way! I have your AOS five frame and I am going to build it this year.👍 Joe
I've seen a ton of people comparing these props to the traditional three-bladed props when it comes to efficiency, but toroidal props are very clearly 4 bladed props. From my ""testing"" they seem to be a good in-between four and three-bladed props, they feel much more "locked in" than three-bladed props but have slightly higher apparent efficiency than the traditional 4 bladed propellers I fly (on the same drone[AOS5v2] with tunes to suit each). However, this is all anecdotal and I haven't done serious testing on this but it may be worth looking into. I honestly think the biggest draw for most will be that they are much less "Screechy" than normal props due to the toroidal shape, which I find is a huge boon when I am flying where I don't want to annoy people or disturb the environment too much. I honestly love the way they feel and sound too, but that is of course a personal preference. I still feel like there is much to be optimized with toroidal prop tech, I mean look at how many tri-blade props there are out there and how much they differ in efficiency and feel; even when looking at props with similar sizes and pitch. Toroidal props aren't the "end-all-be-all" that they were touted in the paper, but they definitely arent the snake oil many people seem to think they are. I hope to see this be explored much more, especially with lower-pitch toroidal props, before the hobby disregards this concept.
Your videos keep getting better and better. This time you found the perfect balance between explaining the methods and data ind detial, and not making it too long. And I really like the new style of your video cutting. Adds really some spice to the information. Well done, looking forward to future videos!
Man I just want to say, your testing is exceptional and thorough. Every time I watch one of your videos I learn something and I marvel at your ability to get and deliver meaningful actionable insights. Also having watched your other videos about your test riggs, I know that the data you are delivering is the best available online, from goggle latency analysis to prop and motor thrust, no one does it better (at least that I've seen) :)
I am wishing for a smaller diameter toroidal prop, to get less of a scream from those 3.5" props, but I have a feeling that with this toroidal design, a larger prop diameter is going to be the way to get better performance. Hopefully that's just me being a little pessimistic, but even if it does turn out so, if a larger diameter toroidal prop gets close or better performance to a tri-blade, that would still be useful, and exciting.
The Foxeer is a four bladed prop, so I think this is a comparison of an unusual four bladed prop with a three bladed prop. Would be more interesting to compare the Foxeer with a four bladed prop of similar pitch.
I test flew some of these. They are slightly quieter than regular props, but extremely fragile. I broke 1 just taking off and 2 landing. The joint at the tip breaks super easy. I had to replace at least one prop almost every time I flew with them. In a normal day of flying with regular props, I might replace 1 or 2. I went through 6 of these in less than an hour.
Everybody is saying the toroidal is more efficient yet all test on YT shows that its not. It sure looks like a high drag design, maybe the research is inaccurate??
The MIT ones have a different profile, I have yet to see a design that isn’t a normal prop airfoil with only the top bent up to join. MIT have a whole different progressive chord and asymmetrical airfoil thing going on with their design that probably is where the „secret sauce“ is.
@@skylar7320 MIT does have one of the worlds leading fluid dynamics experts working for them. He's also a legend in the RC and fullscale world. Not sure if Mark Drela had anything to do with their prop but, I'd be really surprised if they didn't at least ask him some questions.
Love your videos and your channel, however the MIT research paper was using the comparison of the toroidal prop with a bi-blade prop. In my opinion that would have been a more appropriate and interesting comparison, maybe something for the future videos 😜. Said that I understand that in FPV bi-blades are only used for long range and commercial drones.
Excellent video and the noise character was indeed very different Would love a follow up with a bi-blade, quad-blade and a couple of other common Tri-blades
Strictly speaking you're reviewing the Donut prop, not the MIT's prop, they even don't look quite the same. The MIT one might be more efficient and quieter than a regular one, it's just Donut isn't there. Unfortunately, it looks like MIT haven't shared their design, only photos, so it's hard to confirm whether their props are indeed that good.
@@ChrisRosser That would be amazing if they would, I am doubtful MIT would be lying and they did say that it's more effective with larger props due to higher tip speed.
Very informative video. Well explained tests and comparisons. I bought them , flew them, don't like them. They do look good, especially the blue ones. 😎
I believe that toroidal props still have to be perfected in the profile of the blade. The F5 is a piece of art in that aspect and the donut seems like a square compared to the F5 curves.
If the vibration wasn't so much worse, I might take the tradeoff in the other parameters for a lower-frequency sound. I think it's important for citizen coexistence reasons
Thanks for your comment! The sound pressure level measurement is in dBA which is the human ear weighted sound level relative to the limit of human perception and is the correct unit of measure for real world loudness. LUFs is a measure of loudness of a digital audio file relative to a digital full scale (rather than a real world measure) so wouldn't be appropriate in this case.
@@ChrisRosser I totally forgot about that, however assuming you set the input gain on the mic exactly the same, have no AGC engaged, use no compression, and have the mic and prop in exactly same spot for both tests, then it shouldn't matter what 0 dBFS or 0 LUFS is, it would be a relative measurement between the two props, not total peak dB reading in the real world. Then you can use what I consider the more accurate weighting curve of LUFS versus the older A-weighted curve of dBA and then on top of that you get other useful data such as short term and long term integrated values. Taking a momentary dBA reading doesn't give you that. So, for example, you could do a throttle sweep and see wildly different LUFS values even if the peak dBA were exactly the same. It's a better way of conveying the layman's sensation of "THAT'S LOUDER!" from what I've seen. This would require a proper mic, audio interface, ASIO, the right recording software, and a tool like Youlean Loudness Meter 2 et al. It can't be done with an SPL meter or a phone, for example.
As far as I understood from toroidal propellers, a toroidal propeller must have the front apex of blade 1 attached to the rear apex of blade 2 and vice versa. From what I see of these propellers, they do not appear to be toroidal but rather they have simply deformed them and joined the ends of the propellers but without forming a toroidal shape. Maybe with a v2 design where these are really toroidal, these will increase on power and efficiency as supposed to be?
I am happy to see that someone remarked the (obvious) difference (flaws) in the design of this "toroidal" prop. It is far off the MIT design and as such does not provide any benefit beside the sound aspect and the cool look. It is somewhat like those attempts to build a box-wing aircraft using two "ordinary" wings and connect them at their tips with a simple flat brace. I mean, the aerodynamic design of winglets is much more than just a plate mounted vertically. I really doubt that this mass-produced prop has followed the rules of aerodynamics of toroidal props...
on the topic of sound, when it comes to how loud we perceive a sound to be, there's more to it. the toroidal prop is much lower in frequency. our sensitivity to sound is not flat across all frequencies, and that frequency response is not the same through the whole dB range. a sound at say 3khz will be perceived at a different level to one at 100hz when at the same volume. but it can change when played at different volumes . check our fletcher munson curves
You compared it with the best traditional prop, and that performs better than the toroidal prop. But is that still the case if you compare it with a mid- or low range traditional prop?
This is great video and comparison, but I'm still waiting for some toroidal shape according that MIT video/paper. It's different and that is probably the main reason, why noise is not comparable.
These props tend to work best within a certain throttle range, it seems. With a boat, you have a cruising RPM and it's possible to fine tune the prop to that rpm range. In a typical freestyle drone, the throttle range is massive, and you run into some limitations with the 'donut' props. As for the sound, the lower pitch makes it sound more quiet to our ears, I guess, even though the SPL is a bit higher.
Glad Foxeer made these so we can rule out the effects of 3d-printing. Now I just wonder if there is a shape that would actually make our dreams come true. This seems to work well in Water with a super weird shape... so maybe there is potential left for these! Still a bit disappointing all there is to it is a deeper pitch noise paid with a fragile prop and efficiency... I really want quiet props! XD
Looking forward to whoop and toothpick blades of this style if the physics works. Sorry foxeer, but I don't think people will buy. But really awsome they tried 👍 respect, hopefully next time
This exact foxer propeller is like 2 blade toroidal propeller versus 3 blade normal this comparison isn't fair. there still no mass production of this kind propellers , am sure torodail props has lower sound pitch and little bit more efficient but is some downsides, is difficult to balance them and more prone to damage.
When the toroidal prop is producing thrust at high RPM, I wonder whether it flexes so much that the distortion to its shape negates all the supposed aerodynamic improvements. Maybe you could set up a camera to observe the prop flexing when its at high RPM.
I have some of these props, waiting for their turn to fly, looking for how they feel and for how a pedestrian bystander will compare the sound to my usual props. But what I really would love to see, if it turns out to be possible, is a 3.5-inch design of a toroidal prop. I would like to fly my 3.5 quad, with less of a scream, from the props that are currently available.
for the sound characterizing what peak RPM is each prop hitting? The more draggy prop will spin slower and make a lower pitch and possibly softer noise. Using a 8 blade prop for ducted centiliters produces similar if net more desirable noise characteristics to the toro IMO. So far the only time I have seen anyone even try to show a way the toro is better is when they leave out some critical data. For example the last section of noise characteristic leaving out RPM and thrust levels for the noise we are hearing. If a nazgul can spin slower to make the same thrust than a full speed noise comparison isn't really fair.
Is there a reason, we don't get to see a fourier analysis on any video, that Chris makes on toroidal props? Feels weird to have Chris say "hey, just have a listen and decide", whereas he's "the vibration guy" once it comes to frames with all the frequency graphs etc. I'd love to see the fourier analysis of toroidal props and traditional 2 and 4 bladed props overlaid with e.g. the human hearing loudness curve (aka the phon curve).
Great testing as usual. We need someone to figure out why Sharrow Marine props are noticeably quieter in the water and how to implement that for quads.
ruclips.net/video/--F2N2zGV4c/видео.html A test by Boating magazine of the sharrow propeller. I am not into boating so I don't have any experience with it, but I thought Boating magazine was a real magazine, but maybe they paid for the test. Any boaters reading this that have $10,000 for two props to give us an independent test?
Water is a much thicker fluid so the effect is more pronounced. Water also doesn't compress so that is likely playing a factor. I'd be really interested to hear what someone like Mark Drela thinks about the subject, he's the Fluid Dynamics professor at MIT and a legend in the RC and full scale aviation world.
great video !! I'm not surprised by the results as traditional props are alreafy hard to optimize, but I'm curious about your methodology for the efficiency test, did you measure the power coming to the motor or to the prop ? in the first case there could be some margin of error as the motor probably won't have the same efficiency for both propellers
my friend bought the props and flew freestyle with them, and one broke just from aerodynamics. the tip shattered when doing a sharp turn, despite not hitting anything
A couple of questions came up for me: It looks like a toroidal prop, but does it have the "right geometry"? It could be pretty sensitive to minor variations in design compared to the MIT version. Are you turning it at the right RPM? You'd need to at least match the Reynold's number for the air and the size of the MIT prop to start to ensure you were getting the same results. Maybe it's spinning too fast, and you'd need larger props (just guessing) at slower speeds.
Sir please assist me 😢 It's my first Quadcopter I flashed baseflight on my naze 32 bmp280 Problem is quad not using midvalue 1500 as its altitude mode as netrual position. It's using the min throttle value in case of power on the quad>> switch into baro mode>> arm the quad and lift off. And the value of throttle when you switch into altitude hold mode. Please help , i want my quad to maintain altitude at 1500 throttle value.
Hey Chris, what do you think about a “tri blade” toroidal prop. For example, the foxeer donut is basically a “bi blade” toroidal prop. Tri blade might make it better
Regular airplane props to toroidal is a pretty big leap. I know it sounds so simple that someone probably a lot of folk, has already done this but I can’t find evidence of or anyone who has tried putting simple winglets on normal, regular airplane propellers. If they work on wind turbines increasing efficiency 4-5% then…? Yes, one is pushed by wind & the other propels it. But isn’t it to simple to overlook? Seems like ANY improvement would justify a cheap screw on “Neglets”* kit. Right?! Or tested on helicopter blades or even part of your myriad & diverse test propellers. Seriously, how hard could it be to simply add winglets to normally produced blades and propellers be they for air or water. *”Neglets” Negating Vortices Winglets. To simply to patent. Let’s just make them open source/public domain. SemperFi
if the toroidal prop was better it would have been used by militaries🤷🏼♂️ this is the only industry which develops cutting edge technologies which then become available for people
Oh no, not this BS again.... Even if it's more quiet, efficient, powerfull, I jsut don't care if it breaks when it touches a leaf. Great testing anyway, thanks for that, Chris!
Since the very first tests of toroidal props I suspected that they are just another overhyped stuff. Are they quieter than traditional props? No. Are they way more efficient? No. Lighter? No. According to all the tests I saw on YT, toroidal props are just trash. And your test just confirmed it.
The part in the video from MIT when they have the toroidal compared to what looked like a oldschool 9450 DJI prop it was a lot quieter and I had read that larger props have a more noticeable difference due to higher tip speed. I just really don't think we should say MIT is lying because of tests using a completely different propeller and I know the 3d printed ones were not designed with any sort of simulation software to optimize and while I would hope a company would do so they are just for toys after all and even if they used some software to optimize I question if Foxeer had a fluid dynamics expert design theirs.
Wondering how the air creates a "vortex" around the tip of the propeller, when the craft is in motion, and the blades themselves are spinning at tens of thousands of RPM. What you're saying makes sense for airplane wings, but I can't wrap my brain around how it would apply to a spinning propeller blade.
The blades function as an airplane wing going in a circle so a vortex is still created. Check out Vortex Ring State when the vortices on a helicopter’s rotors become so much of a problem that it can crash because of it.
I'm just curious, what makes you say the Nazgul F5 prop is the "best you've tested"? Props are one of those things in FPV that are like rates. They're personal and relative to the pilot.
lol - dude. Rosser does objective testing proving the various differences in characteristics between different props. He puts the data right there in his videos. What are you even talking about? Preference is preference, but there are objective differences in how props handle and perform. That's two different metrics. You're asking questions this guy has answered in great detail in other videos of his.
@@Wind_Rapportwhile I mostly agree with you, there's no way he could do enough testing to cover all of the variables for real-world flying. Like if you're doing proxy and the best overall prop slightly beat out another prop due to its top end efficiency, but you never actually utilize the top end when flying, maybe the "2nd place" prop is stronger in other areas that contribute more value to your real world use case. It may objectively be the best prop, but may subjectively not be the best prop for everyone. I don't even like running anything higher than a 3.6 in pitch, and lately I prefer a 3-3.3". Does that make it a less Superior prop? Not when I'm flying. 🙂
Different props are better for different use cases and flying styles. That's a given. So obviously you will prefer to use different props depending on the use case and what style of flying you want to do. When you say there's no way to do enough testing to compare flight characteristics you are 100% wrong about that, again as proven in Rossers video catalogue. You can absolutely compare superiority in terms of efficiency, noise, thrust, durability, the list goes on. It's funny cause you seem to be trying to say 'nah aint science it's all preference and feel.' The data says that's not true, so many variables are clearly measurable. Rosser's channel has been proving that for years. Anway I don't care at all what props you use@@willpowerfpv3246
@@willpowerfpv3246 Yeah you are 100% talking about preference again. Like yeah man you prefer a certain amount of pitch for a certain use case.. but your original argument was "Rosser can't possibly test every objective variable" - And my response to that is yes you can, and he does, but obviously nobody is taking into account your personal preference as a variable lol. I'm coming to realize that's what you're really arguing about. You should change your RUclips handle to SemanticsFPV, ha I kid. Later
Does not matter how noisy or not it is, this design is flawed and ridiculously weak around the tip area. Totally impractical, move on by, nothing to see here.
How stupid must a company be to develope a product which does not deliver any of the promises? You build a prototype and then check for the benefits. I had seen these results before a year ago about water propellers that also did not deliver at all. Looks like myth busting - or the manufacturers do all get it wrong during production.
Smart companies make products that sell. I'm willing to bet that a very substantial amount of pilots bought these to try out, regardless of what prop manufacturer they're loyal too. Almost everyone I know picked up a couple sets out of morbid curiosity, and I'd be willing to bet that they have already sold enough of these to pay for the molds and have turned a profit. Foxeer was clever enough to bring these to market fast enough to have leveraged the inevitably short lived hype train. 🙂
Appreciate the thorough testing, however it is difficult to judge scales on the graph when its N of 2. Perhaps a couple more context; a standard but lesser performing 2 blade, and perhaps a 3 or 4 blade ? Digging the vids, very informative. Thanks !
I love scientific tests: just repeatable data, no personal opinion, just facts. Great job, as you always do :)
Yeah this guy is awesome. I’ve seen plenty of his videos and they are all top notch :)
There is one more aspect:
At the moment, toroidal props are much more prone to damage.
And if toroidal props get damaged, it influences their functionality much more.
Toroidal props were not invented in 2017. There's published research on prop configs w/ joined tips (toroid, box, non-planar, etc.) going back to at least the 1960s.
dude its 'tube'... don't let facts gets in the way of content
he's talking about the MIT props, that was posted in 2017.
Chris, i’ve been watching your content for about three years, honestly it’s about time I tell you what a great resource you are and spread a little appreciation your way! I have your AOS five frame and I am going to build it this year.👍 Joe
I’m so glad YOU reviewed these because you’re one of a few people that are OCD enough for me to trust you to properly vet stuff so I don’t have to 😂
Thank you for giving credit to those who were willing to take the risk and test out manufacturing them so we can learn in the hobby
Toroidal props sound less irritating... awesome and detailed testing! Thank you Chris, i wish you are my Uni lecturer! 🤩
I agree, my ears liked the noise from the toroidal much more than the triblade.
Foxeer has become my favorite manufacturer.
I've seen a ton of people comparing these props to the traditional three-bladed props when it comes to efficiency, but toroidal props are very clearly 4 bladed props. From my ""testing"" they seem to be a good in-between four and three-bladed props, they feel much more "locked in" than three-bladed props but have slightly higher apparent efficiency than the traditional 4 bladed propellers I fly (on the same drone[AOS5v2] with tunes to suit each). However, this is all anecdotal and I haven't done serious testing on this but it may be worth looking into.
I honestly think the biggest draw for most will be that they are much less "Screechy" than normal props due to the toroidal shape, which I find is a huge boon when I am flying where I don't want to annoy people or disturb the environment too much. I honestly love the way they feel and sound too, but that is of course a personal preference.
I still feel like there is much to be optimized with toroidal prop tech, I mean look at how many tri-blade props there are out there and how much they differ in efficiency and feel; even when looking at props with similar sizes and pitch. Toroidal props aren't the "end-all-be-all" that they were touted in the paper, but they definitely arent the snake oil many people seem to think they are. I hope to see this be explored much more, especially with lower-pitch toroidal props, before the hobby disregards this concept.
Thanks for taking an objective look and cutting through the hype.
Your videos keep getting better and better. This time you found the perfect balance between explaining the methods and data ind detial, and not making it too long. And I really like the new style of your video cutting. Adds really some spice to the information. Well done, looking forward to future videos!
Man I just want to say, your testing is exceptional and thorough. Every time I watch one of your videos I learn something and I marvel at your ability to get and deliver meaningful actionable insights. Also having watched your other videos about your test riggs, I know that the data you are delivering is the best available online, from goggle latency analysis to prop and motor thrust, no one does it better (at least that I've seen) :)
Well done 👍🏼😀 I liked the vibration diagram at 4:58 (tri-blade props are still the best)
Thanks Chris I’m still going to pick some more up as I like the way they feel
You know it sounds lower during the blips at the end... I think your right. If they keep playing with the formula they will get it.
I am wishing for a smaller diameter toroidal prop, to get less of a scream from those 3.5" props, but I have a feeling that with this toroidal design, a larger prop diameter is going to be the way to get better performance. Hopefully that's just me being a little pessimistic, but even if it does turn out so, if a larger diameter toroidal prop gets close or better performance to a tri-blade, that would still be useful, and exciting.
Excellent video as always! Its cool to put some actual data to all the hype we hear about things in this hobby.
The Foxeer is a four bladed prop, so I think this is a comparison of an unusual four bladed prop with a three bladed prop. Would be more interesting to compare the Foxeer with a four bladed prop of similar pitch.
I test flew some of these. They are slightly quieter than regular props, but extremely fragile. I broke 1 just taking off and 2 landing. The joint at the tip breaks super easy. I had to replace at least one prop almost every time I flew with them. In a normal day of flying with regular props, I might replace 1 or 2. I went through 6 of these in less than an hour.
It's a fine example of theory meeting the windshield of reality.
Different spacing (not equal) of the blades is also able to adjust the noise level.
Bro… thanks you a LOT!!!
So cool dude we want more like this, thanks from france
@OfficialChrisRosser hi :) what are you saying ?
New to the channel 🎉 props tp Bardwell for being a patriot 👏🏽
Everybody is saying the toroidal is more efficient yet all test on YT shows that its not. It sure looks like a high drag design, maybe the research is inaccurate??
The MIT ones have a different profile, I have yet to see a design that isn’t a normal prop airfoil with only the top bent up to join. MIT have a whole different progressive chord and asymmetrical airfoil thing going on with their design that probably is where the „secret sauce“ is.
@@skylar7320 MIT does have one of the worlds leading fluid dynamics experts working for them. He's also a legend in the RC and fullscale world. Not sure if Mark Drela had anything to do with their prop but, I'd be really surprised if they didn't at least ask him some questions.
Fantastic testing, Chris! Thanks a bunch! 😃
Stay safe there with your family! 🖖😊
there is so much room for improvement in the design of the toroidal prop they made since getting the efficiency improvement are really hard to get
good stuff!! can't wait for your battery testing!!
Love your videos and your channel, however the MIT research paper was using the comparison of the toroidal prop with a bi-blade prop. In my opinion that would have been a more appropriate and interesting comparison, maybe something for the future videos 😜. Said that I understand that in FPV bi-blades are only used for long range and commercial drones.
@OfficialChrisRosser SPAM ALERT
Excellent video and the noise character was indeed very different
Would love a follow up with a bi-blade, quad-blade and a couple of other common Tri-blades
Great comparison - amazing job!
thanks chris! allway great content!!!
Strictly speaking you're reviewing the Donut prop, not the MIT's prop, they even don't look quite the same. The MIT one might be more efficient and quieter than a regular one, it's just Donut isn't there. Unfortunately, it looks like MIT haven't shared their design, only photos, so it's hard to confirm whether their props are indeed that good.
Yes, I'll reach out to them and see if they'll let me test their design!
@@ChrisRosser That would be amazing if they would, I am doubtful MIT would be lying and they did say that it's more effective with larger props due to higher tip speed.
Very informative video. Well explained tests and comparisons.
I bought them , flew them, don't like them. They do look good, especially the blue ones. 😎
Interesting study you did here, I would say the sound is less annoying.
I believe that toroidal props still have to be perfected in the profile of the blade. The F5 is a piece of art in that aspect and the donut seems like a square compared to the F5 curves.
Thanks for a very detailed and well documented review.
If the vibration wasn't so much worse, I might take the tradeoff in the other parameters for a lower-frequency sound. I think it's important for citizen coexistence reasons
On the sound test you could also do a LUFS measurement to get a more accurate representation of how "loud" it sounds to the human ear.
Thanks for your comment! The sound pressure level measurement is in dBA which is the human ear weighted sound level relative to the limit of human perception and is the correct unit of measure for real world loudness. LUFs is a measure of loudness of a digital audio file relative to a digital full scale (rather than a real world measure) so wouldn't be appropriate in this case.
@@ChrisRosser I totally forgot about that, however assuming you set the input gain on the mic exactly the same, have no AGC engaged, use no compression, and have the mic and prop in exactly same spot for both tests, then it shouldn't matter what 0 dBFS or 0 LUFS is, it would be a relative measurement between the two props, not total peak dB reading in the real world. Then you can use what I consider the more accurate weighting curve of LUFS versus the older A-weighted curve of dBA and then on top of that you get other useful data such as short term and long term integrated values. Taking a momentary dBA reading doesn't give you that. So, for example, you could do a throttle sweep and see wildly different LUFS values even if the peak dBA were exactly the same. It's a better way of conveying the layman's sensation of "THAT'S LOUDER!" from what I've seen. This would require a proper mic, audio interface, ASIO, the right recording software, and a tool like Youlean Loudness Meter 2 et al. It can't be done with an SPL meter or a phone, for example.
As far as I understood from toroidal propellers, a toroidal propeller must have the front apex of blade 1 attached to the rear apex of blade 2 and vice versa. From what I see of these propellers, they do not appear to be toroidal but rather they have simply deformed them and joined the ends of the propellers but without forming a toroidal shape.
Maybe with a v2 design where these are really toroidal, these will increase on power and efficiency as supposed to be?
I am happy to see that someone remarked the (obvious) difference (flaws) in the design of this "toroidal" prop. It is far off the MIT design and as such does not provide any benefit beside the sound aspect and the cool look.
It is somewhat like those attempts to build a box-wing aircraft using two "ordinary" wings and connect them at their tips with a simple flat brace. I mean, the aerodynamic design of winglets is much more than just a plate mounted vertically. I really doubt that this mass-produced prop has followed the rules of aerodynamics of toroidal props...
so this video concludes all the toroidal vs conventional props conversations
on the topic of sound, when it comes to how loud we perceive a sound to be, there's more to it.
the toroidal prop is much lower in frequency.
our sensitivity to sound is not flat across all frequencies, and that frequency response is not the same through the whole dB range.
a sound at say 3khz will be perceived at a different level to one at 100hz when at the same volume.
but it can change when played at different volumes .
check our fletcher munson curves
Keep in mind the MIT 'paper' is two pages long and most of it is fluff like 'drones are more and more common in public'
You compared it with the best traditional prop, and that performs better than the toroidal prop. But is that still the case if you compare it with a mid- or low range traditional prop?
This is great video and comparison, but I'm still waiting for some toroidal shape according that MIT video/paper. It's different and that is probably the main reason, why noise is not comparable.
These props tend to work best within a certain throttle range, it seems. With a boat, you have a cruising RPM and it's possible to fine tune the prop to that rpm range. In a typical freestyle drone, the throttle range is massive, and you run into some limitations with the 'donut' props. As for the sound, the lower pitch makes it sound more quiet to our ears, I guess, even though the SPL is a bit higher.
The Toroidal prop is a 4 blade though is it not? So I guess, will always have the drawbacks of a 4 blade?
Maybe it should be better compared with a 4 blade.
Exactly, the tips are connected, but it’s still a four bladed prop.
Glad Foxeer made these so we can rule out the effects of 3d-printing. Now I just wonder if there is a shape that would actually make our dreams come true. This seems to work well in Water with a super weird shape... so maybe there is potential left for these! Still a bit disappointing all there is to it is a deeper pitch noise paid with a fragile prop and efficiency... I really want quiet props! XD
Looking forward to whoop and toothpick blades of this style if the physics works. Sorry foxeer, but I don't think people will buy. But really awsome they tried 👍 respect, hopefully next time
This exact foxer propeller is like 2 blade toroidal propeller versus 3 blade normal this comparison isn't fair. there still no mass production of this kind propellers , am sure torodail props has lower sound pitch and little bit more efficient but is some downsides, is difficult to balance them and more prone to damage.
When the toroidal prop is producing thrust at high RPM, I wonder whether it flexes so much that the distortion to its shape negates all the supposed aerodynamic improvements. Maybe you could set up a camera to observe the prop flexing when its at high RPM.
I have some of these props, waiting for their turn to fly, looking for how they feel and for how a pedestrian bystander will compare the sound to my usual props. But what I really would love to see, if it turns out to be possible, is a 3.5-inch design of a toroidal prop. I would like to fly my 3.5 quad, with less of a scream, from the props that are currently available.
for the sound characterizing what peak RPM is each prop hitting? The more draggy prop will spin slower and make a lower pitch and possibly softer noise. Using a 8 blade prop for ducted centiliters produces similar if net more desirable noise characteristics to the toro IMO.
So far the only time I have seen anyone even try to show a way the toro is better is when they leave out some critical data. For example the last section of noise characteristic leaving out RPM and thrust levels for the noise we are hearing. If a nazgul can spin slower to make the same thrust than a full speed noise comparison isn't really fair.
This will be very helpful if you share the test setup. Is it possible?
Nice breakdown Chris. I emailed you a while ago regarding marine toroidal hype. Seems it's a bit overblown for now 😂
You should balance the toroidals and repeat the testing. Also check the runout and correct as necessary.
You need highspeed camera to look at prop deflection angle...
They sound more like a weed whacker than a high pitched prop. even thought they are loud the pitch is lower. I might have to try them
Thank You!
Is there a reason, we don't get to see a fourier analysis on any video, that Chris makes on toroidal props? Feels weird to have Chris say "hey, just have a listen and decide", whereas he's "the vibration guy" once it comes to frames with all the frequency graphs etc. I'd love to see the fourier analysis of toroidal props and traditional 2 and 4 bladed props overlaid with e.g. the human hearing loudness curve (aka the phon curve).
Great testing as usual. We need someone to figure out why Sharrow Marine props are noticeably quieter in the water and how to implement that for quads.
Has Sharrow been independently tested? I see a bunch of marketing wank, but barely anybody can afford to properly test them.
ruclips.net/video/--F2N2zGV4c/видео.html
A test by Boating magazine of the sharrow propeller.
I am not into boating so I don't have any experience with it, but I thought Boating magazine was a real magazine, but maybe they paid for the test.
Any boaters reading this that have $10,000 for two props to give us an independent test?
Water is a much thicker fluid so the effect is more pronounced. Water also doesn't compress so that is likely playing a factor. I'd be really interested to hear what someone like Mark Drela thinks about the subject, he's the Fluid Dynamics professor at MIT and a legend in the RC and full scale aviation world.
great video !! I'm not surprised by the results as traditional props are alreafy hard to optimize, but I'm curious about your methodology for the efficiency test, did you measure the power coming to the motor or to the prop ? in the first case there could be some margin of error as the motor probably won't have the same efficiency for both propellers
Hi chris, can you compare efficiency between pusher cinewhoop drone vs normal cinewhoop drone?
What do i win? Haha
I wonder how the comparison would turn out for a prop of the same pitch...
perhaps some blackbox analysis using the torodial prop?
Based on the vibration characteristics he observed, BB would be horrible.
my friend bought the props and flew freestyle with them, and one broke just from aerodynamics. the tip shattered when doing a sharp turn, despite not hitting anything
A couple of questions came up for me: It looks like a toroidal prop, but does it have the "right geometry"? It could be pretty sensitive to minor variations in design compared to the MIT version. Are you turning it at the right RPM? You'd need to at least match the Reynold's number for the air and the size of the MIT prop to start to ensure you were getting the same results. Maybe it's spinning too fast, and you'd need larger props (just guessing) at slower speeds.
I believe MIT mentioned that the effect is stronger on larger props due to higher tip speed.
Why do toroidal propellers work better on a boat than on a plane in the air? What makes it more efficient in the water as opposed to the air?
I think they avoid cavitation in the water which is not an issue in a gas environment.
@@ChrisRosser ha... Great explanation except I don't know what cavitation means 🤣. Speaking to a layman here.
Sir please assist me 😢
It's my first Quadcopter
I flashed baseflight on my naze 32 bmp280
Problem is quad not using midvalue 1500 as its altitude mode as netrual position.
It's using the min throttle value in case of power on the quad>> switch into baro mode>> arm the quad and lift off.
And the value of throttle when you switch into altitude hold mode.
Please help , i want my quad to maintain altitude at 1500 throttle value.
Good informative video. Thank you. These hemoroïdal props are not for me. I crash a lot these times 😂.
That 2207 1855kv has more axial torque compared to radial torque - not designed for that motor.
Compare with 2505.5 2000kv, then conclude.
Hey Chris, what do you think about a “tri blade” toroidal prop. For example, the foxeer donut is basically a “bi blade” toroidal prop. Tri blade might make it better
I see four blades on the Foxeer - you only see two?
@@automaton450 yeah it could be 4 or 2 but im curious how it would perform with 6 or 3
AOS 85 or 95mm whoop please :D
Regular airplane props to toroidal is a pretty big leap. I know it sounds so simple that someone probably a lot of folk, has already done this but I can’t find evidence of or anyone who has tried putting simple winglets on normal, regular airplane propellers. If they work on wind turbines increasing efficiency 4-5% then…? Yes, one is pushed by wind & the other propels it. But isn’t it to simple to overlook? Seems like ANY improvement would justify a cheap screw on “Neglets”* kit. Right?! Or tested on helicopter blades or even part of your myriad & diverse test propellers. Seriously, how hard could it be to simply add winglets to normally produced blades and propellers be they for air or water.
*”Neglets” Negating Vortices Winglets. To simply to patent. Let’s just make them open source/public domain. SemperFi
They should make carbon fiber versions of these. That would be a proper way to fail.
Toroidal sounds waaaay much more pleasant.
So, it sucks. Wait for version 2 or the next OEM to release theirs? *sigh*
Well i prefer the Donut Lower FR Sound
if the toroidal prop was better it would have been used by militaries🤷🏼♂️ this is the only industry which develops cutting edge technologies which then become available for people
M.I.T. LIED TO YOU
Can you fly 3D with the prop?
Yes, for as long as they last, and they don't!
You are comparing 2 blades vs 3 blades. What about the comparison 2 vs 2.
I think the conclusion is, the name of a school or institution does not necessarily mean jack shit.
Donut props 😂
Oh no, not this BS again....
Even if it's more quiet, efficient, powerfull, I jsut don't care if it breaks when it touches a leaf.
Great testing anyway, thanks for that, Chris!
I was hoping they are 3D props. But they aren't...
Summary: its less efficient, produces less thrust and causes high vibrations. Its shit.
Since the very first tests of toroidal props I suspected that they are just another overhyped stuff. Are they quieter than traditional props? No. Are they way more efficient? No. Lighter? No. According to all the tests I saw on YT, toroidal props are just trash. And your test just confirmed it.
The part in the video from MIT when they have the toroidal compared to what looked like a oldschool 9450 DJI prop it was a lot quieter and I had read that larger props have a more noticeable difference due to higher tip speed. I just really don't think we should say MIT is lying because of tests using a completely different propeller and I know the 3d printed ones were not designed with any sort of simulation software to optimize and while I would hope a company would do so they are just for toys after all and even if they used some software to optimize I question if Foxeer had a fluid dynamics expert design theirs.
nazguls wtf
Wondering how the air creates a "vortex" around the tip of the propeller, when the craft is in motion, and the blades themselves are spinning at tens of thousands of RPM.
What you're saying makes sense for airplane wings, but I can't wrap my brain around how it would apply to a spinning propeller blade.
there might be a video somewhere showing this with the help of a laser projection
The blades function as an airplane wing going in a circle so a vortex is still created. Check out Vortex Ring State when the vortices on a helicopter’s rotors become so much of a problem that it can crash because of it.
Vortex does happen, which led to the development of ducted fans. The pressure difference on either side of the prop is huge.
90% of the noise is from the trapezoidal ESC. This test is stupid
If you run the test without a prop on the motor the noise is 40dB less.
I'm just curious, what makes you say the Nazgul F5 prop is the "best you've tested"?
Props are one of those things in FPV that are like rates. They're personal and relative to the pilot.
lol - dude. Rosser does objective testing proving the various differences in characteristics between different props. He puts the data right there in his videos. What are you even talking about? Preference is preference, but there are objective differences in how props handle and perform. That's two different metrics. You're asking questions this guy has answered in great detail in other videos of his.
@@Wind_Rapportwhile I mostly agree with you, there's no way he could do enough testing to cover all of the variables for real-world flying. Like if you're doing proxy and the best overall prop slightly beat out another prop due to its top end efficiency, but you never actually utilize the top end when flying, maybe the "2nd place" prop is stronger in other areas that contribute more value to your real world use case. It may objectively be the best prop, but may subjectively not be the best prop for everyone.
I don't even like running anything higher than a 3.6 in pitch, and lately I prefer a 3-3.3". Does that make it a less Superior prop? Not when I'm flying. 🙂
Different props are better for different use cases and flying styles. That's a given. So obviously you will prefer to use different props depending on the use case and what style of flying you want to do. When you say there's no way to do enough testing to compare flight characteristics you are 100% wrong about that, again as proven in Rossers video catalogue. You can absolutely compare superiority in terms of efficiency, noise, thrust, durability, the list goes on. It's funny cause you seem to be trying to say 'nah aint science it's all preference and feel.' The data says that's not true, so many variables are clearly measurable. Rosser's channel has been proving that for years. Anway I don't care at all what props you use@@willpowerfpv3246
@@willpowerfpv3246 Yeah you are 100% talking about preference again. Like yeah man you prefer a certain amount of pitch for a certain use case.. but your original argument was "Rosser can't possibly test every objective variable" - And my response to that is yes you can, and he does, but obviously nobody is taking into account your personal preference as a variable lol. I'm coming to realize that's what you're really arguing about. You should change your RUclips handle to SemanticsFPV, ha I kid. Later
@@Wind_Rapport my point is, "best" is a subjective term. Which means that in no way can scientific testing determine what is best. 😉
BS of note, not yourself but the props.
Donut sounds better but not worth it
these propellers are 80% hype and marketing 15% of propeller voodoo and 5 % of BS ...
@OfficialChrisRosser what have I won ...? 🤔😉
Does not matter how noisy or not it is, this design is flawed and ridiculously weak around the tip area. Totally impractical, move on by, nothing to see here.
These propellers are totally sucks in one more area - durability
How stupid must a company be to develope a product which does not deliver any of the promises?
You build a prototype and then check for the benefits.
I had seen these results before a year ago about water propellers that also did not deliver at all.
Looks like myth busting - or the manufacturers do all get it wrong during production.
Smart companies make products that sell. I'm willing to bet that a very substantial amount of pilots bought these to try out, regardless of what prop manufacturer they're loyal too. Almost everyone I know picked up a couple sets out of morbid curiosity, and I'd be willing to bet that they have already sold enough of these to pay for the molds and have turned a profit. Foxeer was clever enough to bring these to market fast enough to have leveraged the inevitably short lived hype train. 🙂
So we could try them
Appreciate the thorough testing, however it is difficult to judge scales on the graph when its N of 2. Perhaps a couple more context; a standard but lesser performing 2 blade, and perhaps a 3 or 4 blade ?
Digging the vids, very informative. Thanks !
omg finally someone showed that these props are absolute garbage, they were just hype because MIT invented them, which is not even true...
I much prefer the sound of the teroidals. Deffinitly going to run 3d printed ones on my drone 🤘