Toroidal propeller vs 3D printed EDF 

Here you can find the files for my EDF: www.printables.com/pl/model/791122-3d-printed-toroidal-edf

The point of toroidal propeller is to decrease/spread the harmful vortices that form at the blade tips. Proper EDF has practically no space between the blade tips and the duct wall so vortices have nowhere to form. So toroidal ducted fan does not make sense

Putting the test and results aside for a moment, what really delights me is seeing bright young people like this doing great things with their time and energy. Well done to Nikodem and everyone like him.

The demos, so far, are radially-fixed pitch. Since you're 3D printing each one, try experimenting with a radially-profiled pitch. You will achieve a better stall response and a wider, linear-region in the thrust-speed, response-curve... as you account for the changes in tangential prop speed, from hub to tip. A good starting point, is to assume decreasing-pitch as radius increases. This allows for the tangentially faster portion of each blade to create less turbulence and efficiently scoop air.

Cześć Nikodem, coraz ciekawsze a zarazem bardzo profesjonalne tematy poruszasz , tak trzymaj !

The gap between the shroud and the propeller blade seems to be pretty big. That lowers the performance quite a bit as a vortex can form there. Other than that, good job!👍

Interesting tests! One thing to also consider is that an EDF on a vehicle doesn’t normally see incoming air at 0mph. If it’s on an aircraft, it’ll be seeing air at flight speed, so the necessary pitch changes. Racing RC planes often have such aggressive pitch that the props sound terrible and don’t generate much thrust until they get into higher speed air

I really like your videos. You already got really good advice. I look forward to the next video. Good luck!!!

That's one hell of a pitch you've got there. It's mainly rotating air rather than pushing it. I'd guarantee the thrust would greatly increase with a shallower pitch.

The Best example i've seen of this new toroidal prop is underwater in propulsion mode. It moves almost twice as far with the same amount of power as the old school prop. It's a game changer and that's is something you'll believe soon.

I think the toroidal shapes you generated were suboptimal and would need further tuning. Better shapes are likely more soft organic shapes. The key benefit of these toroidal propellers as far as I have seen is when they operate at low to medium thrust and the efficiency drops off compared to standar propellers towards the high end of thrust. I am not at all surprised of these results. Neat to see non the less

I loved how you said "propeller" Thanks for the video. Keep it up!

I'm a big fan of this video 😂. Looking forward to seeing more

Great experiment, kudos

The best thing about toroidal props is that they're more structurally viable for 3d printing. That's really about it. The 1 most interesting prop would have beeen... a 2-bladed toroidal prop. You probably could have printed the props in ABS and then easily acetone smoothed them. All your results need to be correlated with power.

Just a little question : When measuring effective thrust, did you take into account that as the edf's center isn't at the fixing point of the strength gage, as it is further, the lever increases and the measured force doesn't represent the real thrust

I appreciate your efforts.... Great results ❤

For a fixed thrust value you set, can you vary the propeller radius and measure the full frequency spectrum again? I wonder what size the propellers need to be to have the dB for all frequencies to be less than some set value. Then you could increase the thrust and vary the radius all over again and see the frequency spectrum. Then you can make a 3D plot of thrust vs radius vs dB (max) or dB (average) for the spectrum.

Use resin printer for smoother details, or use cf pla from Hatchbox etc for hiding layer lines. Also use resin mixed with starch to coat, cure with UV to hide layers

Great video as always - but make sure you explain what initialisms/acronyms stand for. I have no idea what EDF is and it is hard to even understand what your video is about without you providing that info.

Did you calculate efficiency as grams thrust per Watt? That would be more interesting to me that just pure thrust.

If you want to increase thrust you have to integrate the propeller in the turbine by changing the design of the turbine. You shouldnt have any gape between the inner side and the propeller, this design decrease air pressure under the propeller. The best is to create a channel to let the propeller spin freely, like being slightly shorter in diameter size than the propeller and making an inner section to integrate the propeller's movement in the inner side of the turbine.

That was really interesting. Now I know that if i want want to reduce noise, toroidal is the way to go

Looks like the normal with more blades has more thrust, maybe the Toroidal needs more blades? Also what about the toroidal tilt/Pitch factor vs the normal. Would a toroidal with say 8 blades be possible? No idea. You really need a fluid dynamics model (MatLab?) of the toroidal to play with. Very nice work! Are toroidal blades suitable for Jet engines?

You have committed proper science

Did you do the same test without the duct? Also be aware of ductless propeller systems including stators near the fan (instead of contra rotating fan). Ty

Great idea!

Hey, thanks for the video! Really Interesting tests. Maybe to improve it further you could try reducing the gap between the propeller and the duct to make the duct more effective? One way I can think of doing this would be to print the propeller slightly too large to be able to spin without rubbing, then just let it run slowly until it shaves enough material off of itself to spin freely

Sir, you are designing stuff and making it at home and doing as close to scientific tests that you can. With the tools you have available on a home budget. This was an awesome video. And you were able to not only display differences between your test samples but were able to highlight the more minute differences. I'd like to see more of your videos. And as a thought on the results and figuring out how to make an improvement. My personal opinion is to start looking at the propeller basics. Surface area and pitch. Followed by weight. The goal to take a commercially available EDF turbine blade, figure out the surface area and pitch to get a baseline volume per revolution of the prop. Then design a terroidal prop with the exact same volume per revolution. And make it lighter than the commercially avaliable prop. Volume per revolution gives you a baseline number that also gives you baseline drag that the electric motor is put under. If rotating mass is identical and volume per revolution is identical then your electric motor efficiency should be close to identical. As in amp draw and rpm should be identical. Eliminating the variables in this way should allow you to get better data on thrust and decibel levels when comparing the 2. I use to build and fly r/c foam board construction aircraft and indoor gymnasium flyers. The electronics were the hardest part to get an efficient and light setup. And then quadcoptors showed up and all the skill in getting something tiny to fly and fly it well turned into who could afford the newest and better quad. Then the government crackdowns on the hobby happened and I didn't pick up a remote until recently.

The thing that most people don't get is that toroidal propellers are designed to be efficient when there is no sleeve/duct - see use on boat motors. To compare apples to apples, compare the thrust of the conventional and toroidal propellers without a sleeve/duct; a good test would be on quad copter droids.

Where did you get that collapsible work bench? It's sweet!

In principle I like the idea of such a test. But why outside with extra wind? And how often did you charge that battery? If you didn't charge it again and again then the battery charge will make a big difference. How about doing this indoors with a power supply like you have on your bench?

I would like to see the same tests but with a lesser gap between the propeller and the cowling. Thank You

Look into the Tubercle effect and the Siemens low noise comb design inspired by owls. Very good projects to 3d print AND combine with the toroidal propeler.

I'd love to see the difference on the actual fan. Same diameter, same number of blades. Which one will draw less power from the AC outlet?

For context 6dB is double the power. 10dB sounds twice as loud

Nice. If you were able to test these same designs under speed or in a wind tunnel, you'd have different outcomes... Mabe blow a leaf blower into the intake to see what happens. Some would cavatait more, others less. Some would be more efficient based on inlet speed. Keep testing!

I admire your intellect great video...

i am more interest with which have more thrust efficiency if use it on plane. hope you make more test and have more info. thank you !

Nice vid thanks ❤

Yes, repeat without the duct! A ducted fan with the least gap between fan and duct is the most efficient as you can see on large jet planes. Compare toroidal to a standard open propeller.

And if you use a toroidal screw without a casing? What will be the thrust?

why didnt you just do the acetone smoothing? Or whatever chemical they use for evaporative smoothing

I actually believe these are not toroidal props as a toroidal prop has a curved edge along the outside instead of just being slanted sections of multiple tubes arranged around a center point.

the next step is to compare a thrust of all propellers at the similar noise - level!!!!

It's a really interesting test. I think it's a good idea to compare thrust/watt + the decibel level at the same amount of thrust (because if a prop got a lower efficiency, it's not surprising the noise level got lower at same rpm or watt). I wonder about 1 thing, all EDFs seem not to consider by design: The efficiency is close related to the gap between the tips of the propeller and the case of the EDF. The more you scale down, the harder/impossible is getting the tolerances right. So why not reducing the gap between the wing tips and the case? -> Let the inner side of the case be a part of the propeller and rotate and the outer part of the case behing fixed.

So how are you going to change the pitch as needed to optimize performance ?

Great Video

How about trying a standard propeller with a ring on the outside that bind the blades, and prevent the air to escape outside the blade rotation? I'm not English so it is somewhat difficult to put my mind picture in words. It should be clear what I try to say.

That was a successful test. Well done. $

Im just curious how it perform in winged aircraft like rc plane, I know it was built for boats and drones but, just how?

Pretty cool

Did you also log input watts vs output thrust?

Thank you What about rim propellers?

Good start, but there are a bunch of parameters and conditions to get a good comparison, keep up the good work sir:)

the idea for using toroidal is to avoid the need of a tunnel

would be interesting to see the difference in denser liquid than air, like in water what would be the difference in power to trust difference then?

Weird question: What kind of glasses are you wearing (blue rim with metal temples?)

Are the two types of propellers the same weight?

The thing that gives a toroidal propeller it's advantage is that there's no edge where high and low flow regimes can mix to create eddy currents, which is already minimized for the EDF. An open fan would be a different matter, but that's already been shown...

You can reduce the noise of the fan by making the spaces between the blades different. Balancing it becomes a challenge but Airbus Helicopters has done it with their fenestrome tail rotors.

I thought the toridal pulls from more flow from outside its area. Try doing the experiment without the enclosure.

wery cool saludos desde Venezuela

If you refrain from using domain specific abbreviations it will make your content more accessible to folks not sharing the same lingo / focus.

Wouldn't the shroud severly hinder the toroidal propeller? The Shroud is a plus only for the regular propellers and putting a toroidal is like adding a second set of plane that will work as an anti blade.The attack angle for the toroidal is going to be slightly different on the tips. Try adding more space between the shroud and the tips of the toroidal blade.

Maybe you could try one of these Archimedes logarithmic screws that everybody talks about for wind turbines

Is it possible to set the rpm and, then, test the propeller? Maybe, … use an oversized, high torque motor like grinder. I think the small motors are set to a certain rpm but if your thrust, propeller blade angle, is different, you will get different thrust because the motor will spine at a higher or lower rpm. Ounce, rpm is set, then tweak the design. Otherwise, you will be guessing. I did see a boat test where they tested efficiency of propellers by watts used, but I think efficiency of a motor depends on sizing the perfect propeller for the motors output.

Birds have lots of feathers to decrease noises and air resistance. You have to make the blades' surface be seemed like bird wings.

Sanding propellers is, like you said, not really practical. But what you can do is print a part with ABS and give it what is called an Acetone Vapour Bath. That will give it a smooth surface finish...

How many degree is the blade toroidal?

I have a concept design for suction propeller aimed to push the limits of dry thrust, I dont have a 3D printer but I do 3d modeling and designing in rhino for industrial designers. I wish you look at the design and try its thrust.

I think your angle is too aggressive on the toroidal propellers - maybe dial them back to no more than 45⁰ at the tips? Also, if you can increase that angle as you get closer to the prop hub it should move air more efficiently as well - just look for Sharrow boat propellers as an example. Best of luck!

Share a link, u hv 100s of video s, I want to see padestal Fan experiment

Wow now i know thanks

The real question is: where can I find that quick fold out workbench???

Now try Tubercle effect blades please! :)

First thing I'd suggest would be a resin 3d printer. You'll get much higher resolution, smoother surfaces and stronger parts. FDM is rubbish for anything near engineering tolerances.

A very good presentation ✝️🇺🇸😀

My guess would be ducted fans are not a good application for toroidal designs as the tip losses are negated by being in the duct

HYPE, what about 103% improvement on boats!

A good idea would be to do a noise test indoors without no prop installed to find out how much of the noise is coming from the motor. I suspect the duct is acting to magnify the motor noise and most of the noise is probably coming from that. But that would be a bit off since the motor won't be under load. Still would be interesting.

4:04 you said just for fun or just for fan? ;)

It would be great if you could design a significantly quieter and less harsh noise for a propeller design for drones!

What about power consumption between them?!

You could messure the sound in sone with also take the annoyance in to account.

Errr .... those aren't toroidal propellers, just some silly angled extrusions. That aside, as others have already pointed out: ducted fans don't have the kind of tip vortices that toroidal props are meant to reduce. Toroidal propellers might be useful for drones, tho. Many models have "ducted" props for safety reasons and with the large gaps between the blades and the duct walls they're often right in the spot where the ducting doesn't add any efficiency but increases noise.

So far, in ALL the Normal vs Torridal prop videos that I've watched, the Torridal is always quieter, but no one compares the thrust and power used by the normal prop or fan running at reduced throttle that matches the torridal noise level.

Toroidal propellers should be used to generate more thrust to lift more weight instead of using it as a normal turbine blade for forward movement . Close the back of the motor with the toroidal prop and flip your motor facing downwards .run a test using the same with the turbine prop and you should notice you'll achieve more lift with thé Toroidal prop than your Turbine prop but using equal energy on both . Thus in Evtol , instead of using 8 motors and blades you can reduce the weight by using 4 motors and 4 toroidal props instead of 8 of each . Combined with 2 side mounted turbine prop motors . In theory and provided you are a great pilot and know wind force and flow , you would be able to land the Evtol safely if all motors had to fail with toroidal blades .

Has anyone added trailing edge scallops to the toroidal prop?

I wonder what an EDF is?

i think its good you only use 3s, impellers (not propellers for EDF´s) are AMP hungry and you can very easy burn the motor trying different impellers on full throttle. i am also pretty sure the 3d printed impellers was flexing to much to give proper thrust for it´s design. i think you might had a bit lower thrust due to impellers flexing. at peek RPM.

Hola Nikodem, buen trabajo felicitaciones, puedes realizar turbinas ?, y si es así, te invito a desarrollar algo realmente revolucionario e histórico.

What about a silencer?

How about check the motor only sound without propeller. You may estimate noise which is generated by propellers. Anyway good jobs!

Would have been cool to see the bought edf compared to the ones you made..

ok - what comes after toroidal?

Compare standard blade with ducting to cycloidal blade without ducting, and reverse.

What if you curved the blades of the toroidal propellers in the same way that the blades of a jet engine are curved?

Next is do a comparison between these propellers and a newer research tubercles or bionic propeller.. I tried finding on RU-vid no one made a homemade video on it yet..

Toroidal propellers are made for open fans, it doesn't make sense to use them in ducted fans. Toroidal propellers are solving problems like tips vortexes etc. that only exist in open fans, and you have other problems with ducted fans like how to keep gap minimum etc.