Coanda Effect Drone Propulsion

[@isthataprogenji4741]

>The domes are almost impossible to print on a FDM printer What if i told you... that you can flip the model upside down? :)

[@kunjukunjunil1481]

Lol underrated comment

[@noble.george]

Even I thought of this. 😅

[@Mixima101]

I was thinking this too.

[@pologamero2648]

But thenthe support are outside instead inside but still are there.

[@dudemcgee256]

@@pologamero2648 curved surfaces are self supporting.

[@encellon]

I spent a long time testing propulsion in a partial vacuum chamber to see what might work best at Mars. As it turns out, ordinary propellers beat every other option hands down. My advice when converting electricity into thrust... Use a standard rotor profile, size the tip-to-tip length just below a length that would send the tips supersonic, and you will get the most thrust possible.

[@thomasrichardson6470]

That's really cool!

[@absbi0000]

Awesome stuff

[@r-gart]

This is the type of insight that is worth a million dollars!

[@bleedgoat]

where were you when i was doing my masters in electronics engineering and went through 7 months of hell? (the props i got were bad profile and i didn't even consider tip to tip size)

[@siffoine]

That’s what she said!

[@Oli420X]

Considering the obtuse and complicated nature of this - you should be pretty proud to get it working first try

[@gominosensei2008]

First? have you seen how many iterations of impellers and domes he had? just because he showed us the (marginally) working one, doesn't make it necessarily the first try. but making (even timelapse) video of the process would probably make this boring for a lot of people on youtube. so it is easy to get tricked.

[@Oli420X]

@@gominosensei2008 it was in the air and relatively controllable on the first try, yeah it wasn't perfect, but I know myself and many others couldn't have done it

[@Oli420X]

@BigDDaddy yeah, the weight, complication, extra cost and possible reduced thrust means it isn't worth it

[@scheve332]

@@Oli420X not flight thought, ground effect.

[@Abdega]

Obtuse rubber goose green moose guava juice Giant shake, birthday cake, Large fries, chocolate shake!

[@lunarlith]

"Honey? The neighbor is making UFO's in the backyard again!"

[@prolska]

looks like a stolen joke that is not even close to funny

[@magapefarmshomestead6453]

Lol

[@nicktube8637]

@@prolska shut up it is funny

[@wesleythomas7125]

"Just ignore it, Harold..."

[@dominicmurar8427]

Speaking of honey why don’t you check out today’s sponsor

[@leifhietala8074]

Just curious why you didn't print the dome as a bowl, with the open side up.

[@colaturkalures]

lmao

[@majinstreams8127]

Lol I thought the same thing but assumed that the flat surface would force a flat print on the bowl essentially giving the same end results but obviously I’m not sure lol

[@salty_sausage]

but then the lines of the 3d printed surface would be perpendicular to the airflow

[@EvenTheDogAgrees]

@@salty_sausage And then you smooth it out with acetone vapour, or a filling primer and fine sandpaper. My guess is that a smoother surface would work better than the irregular surface of a raw 3D print anyway.

[@ms2pranav]

Everyone improvises. Me u him and all 👍👍

[@Siamect]

Call me a traditionalist, but I prefer my drones and the tomatoes in separate formation. Great video as always. Well done!

[@ratheonhudson3311]

Tomatoes matter :) Wait, you said you have a preference for tomato formation? 3D-printed-tomatoes in attack formation!

[@EricAtRandom]

@@ratheonhudson3311 Attack of the Killer Tomatoes in 3D?

[@mossm717]

Call me a traditionalist, but I prefer my aircraft made from wood and canvas. 😝

[@ratheonhudson3311]

@@mossm717 I think tomatoes make a biodegradable aircraft. I'm not sure if you can 3d print canvas yet... I say yet. Everyone has a preference :) maybe someone can attach a real set of tomatoes and thoroughly test out this aircraft. Us traditionalists must protest this.

[@ratheonhudson3311]

@@EricAtRandom Forget Sharknado, I'm scared of TomatoNado or MatoInvado,

[@MichaelSteeves]

I love the fact that nowhere in this entire experiment is the question "why?" even considered!

[@wesselgeldenhuys6103]

The "why" would be to create safer drones.

[@QuantumFluxable]

@@wesselgeldenhuys6103 a wire mesh around the propellers would be far more efficient at achieving that goal. I like "because it's cool" as a reason.

[@KJFMZ]

Because playing is how we learn things :)

[@PeteSnipe]

Lower air pressure per unit area on the ground suggests less chance of setting off a mine?

[@grandaddyc]

@@wesselgeldenhuys6103 For the toy market a simple model similar to this, which is altitude limited and has simplified guidance, if fitted with cheap FPV would reduce the skill factor required and make them more popular and safe, about a meter altitude would be good.

[@jjones6336]

This is an awesome example of experimental engineering. Sure, it didn't result in a faster, more efficient, or better drone, but it WAS an interesting exploration of using the coanda effect. Experimentation and sharing what you learn benefits us all. Cheers, thanks, and keep thinking outside of the box and trying new things! Thumbs-up!

[@FelixBradley]

Also under the bowl is convenient storage space, at full size it could be excellent transport.

[@GregPeden]

Huge problem with this design... propeller airflow cools the fan motors, impellers don't cool the motors at all.

[@Plur307]

Some quadcopter motors like brotherhobby tornado series have built in impellers that will cool the motor. This would be a good application for them.

[@janegerrard1073]

Coanda effect is used in notar helicopters to enhance safety by reducing complexity and likely points of failure, but his drone re-design adds complication and is unnecessary, there's no reason for it.

[@patroberson6952]

Put a hole in the center of the top of the Dome put the the propello on the inside of the Dome it will suck the air through the center of the Dome and will work properly it doesn't need to be on top of the Dome it needs to be on the inside with a hole in the center of the Dome on the top it will work more efficiently

[@hansvanderlinde4020]

@@patroberson6952 Agreed The impeller doesn't blow air downwards but sideways - he was getting lift only from the vacuum formed on top, if mounted INSIDE the dome then you will have great vacuum on top and good pressure build at the bottom.

[@hansvanderlinde4020]

actually, come to think of it, control might turn into a bit of a problem though :-)

[@CaliMeatWagon]

Tom : Propellers are stupid for this Also Tom: Propellers are better for this.

[@frac]

Hmm. The domes also prevent the motors from getting a cooling airflow... is that an issue?

[@descent8275]

yes

[@laughing747]

Coanda effect and ground effect, most ambitious crossover i've ever seen

[@OutpostBravo]

Ground effect is super interesting

[@kadmow]

Tom you are missing the "Coanda Duct", that constrains flow and increases the velocity. This may (or may not) make this device work better. OR, one large coanda body scales better.

[@thomasflamme7937]

The use of a duct may help as you said, as well as outlet guide vanes after the impeller which may help by reducing the loss of thrust due to downstream giration

[@listcheck]

if he put the impellers inside the domes, and props on top of the domes, it would fly like a champ

[@rzkharris]

@@thomasflamme7937 maybe even build some slight 'v's in the sides of the dome since he's already 3d printing it. Also, I wonder if a balloon could work since you only need the shape to create the effect lol.

[@JimCGames]

I agree. Another funnel type dome that sits over the propellers and the lower dome should constrain the air flow and create greater thrust since the air coming through the propellers are simply free to exit anywhere/everywhere. If you look at the initial video demonstrating the effect, you see much of the air goes down, but not all of it. There is no constraints to keep all the air contained. Additionally, I would think that smaller domes might suffice. Particularly since double domes would increase weight. If you google “how does jet thrust work”, you’ll get a better idea of what I’m trying to describe.

[@excitedbox5705]

Impellers will never work well. They push air the wrong direction.

[@gordonyoud5975]

Suggestion, Shorten the skirt/lower part of dome, it does not add to lift but only adds weight

[@cameronwhigham8253]

Agreed

[@DrewLSsix]

How do you figure? This design has been developed by smart people over many years. At a guess I would think that doing what you suggest would defeat the function of the device by reducing pressure within the domes.

[@aswallace88]

@@DrewLSsix There's gotta be a point at which the size and weight of the dome is greater than the air effect under it. I think what Gordon is suggesting is playing with the size and shape to see if there's a balance that can be struck that would still create the effect without the added weight dragging it down.

[@CountBasie56]

Yup. Totally agree.

[@Tomken8d2]

I was thinking that too but also make the domes smaller in diameter.

[@deformemvita]

Have you considered extending the domes into an aero spike? Laminar flow is beast.

[@odiewan67]

Beastie laminar flow :)

[@paulweisgerber7654]

I was thinking about more of a frisbee shape, but with more of a peaked center. Curl the edges in a bit more to pull the air down.

[@davidbowman2404]

Awesome idea, also make the domes inflatable like a zeppelin, filled with helium or hidrogen.

[@GXTRON]

**Destin intensifies**

[@rich1051414]

That would ruin the ground effect but would likely increase lift by a lot.

[@InformantNet]

I am aware that this video is 3 years old, but I don't understand why you didn't just use 4 lightweight salad bowls. They're smooth, symmetrical, and cheap.

[@joalmeria891]

I think the way you explained the Coanda effect with the curved plastic instead of a spoon like everyone else does is unique and more engaging. Great video by the way!

[@mellis966]

Hi Tom, Nice Project! This system works on a skin boundary layer effect. The current impeller design system is flinging air away from the surface boundary. You need to print a funnel housing for the impeller design to increase at surface air flow velocity. What you will find is that the stronger skin effect creates a flow entrainment effect that causes ambient air to flow along with it. ... So even though the funnel housing adds weight it causes the impeller flow to be much stronger. A second thing that you can and should do is to create small stand off wings in the skin effect flow channel. (They act like stators in a jet engine.) What this does is it redirects the air into a more downward flow direction. With your current design the flow is traveling in a spiral over the domes. You want the flow to be as close to vertical as possible. ... The other thing that can be done is to use a second impeller on the bottom. This sucks air in from the center and pushes it out toward the edges. This dramatically improves flow drag performance. The outer flow and bottom flow meet at the edge and eliminate turbulence... All that said these types of lift systems are just not as effective as props. They are used for lift craft that come into contact with physical objects. .... Try those changes and hit me back. You should be at about 65-70% power efficiency of a direct prop system but you should break ground effect. ... Cheers!

[@bradarmstrong3952]

Impressive ideas. I was also wondering if an outward curving intake horn tightly attached to the top perimeter of the impeller would prevent air from wrapping around the impeller and being pulled through again, thus increasing efficiency of the impeller. The top curved surface might even generate another small bit of Coanda lift. Alternatively, the "funnel housing" described by M. Ellis could be curved back outward to create such an intake horn.

[@akc7100]

My understanding of helicopters and air planes is that the wings/rotors do not exactly produce thrust, they create a vacuum that pulls the vehicle up. I agree with the part about needing housings for the fans though. Several resemble turbo rotors, which do require housings to make good use of air flow

[@mellis966]

@@akc7100 I'm a fixed and rotary wing pilot. Wings throw air downward. The wing throwing the air causes Action and Reaction. Wings do this because air is accelerated by compression pressure, surface boundary effect causes the air to redirect downward.

[@JoeOvercoat]

Using a slot at the exit of the impeller fan would greatly improve the boundary layer influence, yes.

[@Tophat-oi6mt]

Could you use an aerospike like 'nozzle' on the bottom to increase trust and efficency, potentialy outwaying the weight penalty?

[@Touj-jp2dt]

I think this would create a region of low pressure under the drone, which would negate the lifting force, and hence would not improve the efficiency, but instead decrease it.

[@craigcorson3036]

*outweighing

[@Altkinx]

Curious how the size/shape of the ‘bowls’ affects efficiency.

[@gugamovies]

yeah I was also curious if while still using the impellers, having a slightly larger set of "bowls" attached over the existing "bowls" would create a venturi tunnel in the remaining gap and help thrust.

[@fresheFresse]

Always good for fun video involving flying machines

[@iBeast_M0de]

Simple impellers by design are way less efficient than propellors. Even though the propellor version flew better I like the impeller version more since it’s a radical different way of creating lift.

[@DigGil3]

@Klippy Klop The video.

[@iBeast_M0de]

Visual_Vexing Thank you, @Klippy Klop need I say more? I said ‘simple impellers’ like the one in the video

[@Enthropical_Thunder]

Well, while this isn't completely wrong, such types of impellers can also be very efficient but at much lower fluid velocity, like you would have in a fan. Also, he probably should have used redirecting vanes, to get a straight airflow, that was probably his major mistake, wich costed him the most efficiency. I did wonder, why he wasn't printing a radial compressor, tp my knowledge, it is very doable with the right size.

[@renierdebeer3629]

@Klippy Klop The efficiency is lost as the impellers does not have good intake (LP) and exhaust (HP) separation and pressurized air is cycling back into the intake. This is also the reason for the high throttle requirement to lift-off as most of the pumped air simply curves back to the suction at lower velocities. It may be more efficient if the top plate of the impeller had a radius toward the center raising its height by at least the height of the blades (see autodesk.i.lithium.com/t5/image/serverpage/image-id/349301i742D77EAB47B2462/image-size/large?v=1.0&px=999). This would increase the compression (thus creating higher output velocities at lower speeds) as well as generating a larger separation distance between intake and exhaust.

[@thetrolle]

Impellers need ducts to work. Mostly for the incoming air flow and to increase airflow speed. Think turbos, ww2 air sirens etc.

[@Flojer0]

I wonder if pressure could be leaking between the pieces, perhaps sealing the tomatoes off could improve efficiency. Also, missed opportunity not printing the toppers in green.

[@NiftyShifty1]

Wouldn’t the extra glue add more weight?

[@iorekbyrnson7173]

@@NiftyShifty1 it will definitely add some weight. I would personally "weld" them together

[@AndoniOlea]

@@iorekbyrnson7173 using a very potent cyanoacrylate.

[@Flojer0]

@@AndoniOlea I was thinking tape, but that sounds even better.

[@AndoniOlea]

@@Flojer0 For best result, I would recommend using a high density polystyrene to make the bell shape, since cyanoacrylate works better in polystyrene than in normal PVC. Also if you are careful enough, you would not even need adhesive, since you could carve it directly. It can be done in a thousand ways.

[@rollmeister]

The air screw is the most efficient way for thrust.

[@openskies11]

That's what SHE said! ;)

[@odudex]

The domes create the Coanda effect, but also create a huge drag and turbulence under them. Maybe a complete "drop" shape under the impellers could improve efficiency. The "drops" could be helium filled balloons. And impellers big, low rpm (low KV motors)

[@paulklement4274]

This helium idea is actually really cool, he could increase the size of the bowls and just stick a Baloon into them, fill it up and with the gained buoyancy, actually use his impellers Edit: spelling

[@colleenforrest7936]

Try a cantenary shape. The cantenary should deflect the oncomming air in the direction you want. Maybe close off the bottom with a shallower cantenary or parabola. I know that makes it look more like a UFO, but ignore that. I did the math once, it should work. There's a suction effect that takes place when air whips around the edge of the opened bowl. A closed bowel bowed outward prevents this. The shape matters. Think of it as creating a lens, but you're using air instead of light. Helium inside the domes is a good idea, as well, but you need to make sure each balloon is filled with near exact the same amount of helium because the differences are going to become more and more aparent exponentially with time. Might do better with a central hub as a single helium chamber.

[@jjrusy7438]

@@paulklement4274 it would be really awesome if he could use only balloons and skip the bowls. that would eliminate 300grams or so

[@kesslerderkonig7455]

Had the same idea but I can't try it unfortunately...

[@joshuapace636]

This is genius... cheers

[@machiii7394]

>They're (motors) going to get quite warm What if I told you... that propellers are meant to both cool the motors and lift the drone? :)

[@honkhonk8009]

no shit

[@airgliderz]

Captain obvious ...!

[@uggranpops8442]

because the air is supposed to be directed horizontally from the motors for the effect to happen

[@matthewhubka6350]

What if I told you... a simple rocket engine doesn’t need cooling and produces more lift

[@uggranpops8442]

@@matthewhubka6350 it's single use

[@nemovulture]

TBH, when I first read the title I read "Canada drone"

[@matthewgrisnich1769]

Same here.

[@nagaming6209]

Yes me 2

[@nagaming6209]

Yupp

[@hugojaime9565]

I first read cocaine drone

[@pootisbirb6683]

Same

[@Tmidiman]

This is how DiVinci got started. Theory, trail, error, improvement. Keep at it!

[@4thWardTechnology]

Flip the bowls so the dome is on the bottom and you won't have an overhang problem when printing. Also you can do vase mode and make them super light.

[@alexanderwatson9845]

Just what I thought

[@ahaveland]

The overhang problem then starts as the layers leave the bed at an extreme angle instead of at the end of the print! Printing on a lathe at 45° instead of on a bed would be able to solve it if such a machine existed.

[@alexanderwatson9845]

@@ahavelandSupports could be more easily and tidily removed if printed upside down. I have no experience with lathes so I cannot say anything on your idea!

[@ahaveland]

@Klippy Klop No, I meant using the lathe as a substrate - the printhead moves in X and Z, and the lathe rotates so the built surface moves at millimetres per second. Filament is extruded as the lathe rotates and the bowl is built up, with no overhang greater than 45°. Is that clearer now?

[@beans2874]

Tom Stanton The Last Air Bender

[@bigjoshlevine]

I'd love to see a test of just the impellers without the domes. I'd expect there to be some lift just because of the low pressure directly above the impeller.

[@ronrothrock7116]

That is a very good thought. What if what we are seeing is not the Coanda effect, but he's just "sucking" the drone upward?

[@nagaming6209]

Hello did I just interfere a long conference

[@ausintune9014]

@@ronrothrock7116 yeah but it'd also cause low pressure on the bottom as it moves up so it'd produce very little lift at most

[@xavierrodriguez2463]

@@ausintune9014 it wouldn't be fast enough to create a low pressure zone below it that caused by drag. Which Is what I assume you mean.

[@brianmacker1288]

@@ausintune9014 Which is also happening with the domes. The air passing over the bottom lip of the upside down bowl will entrain the air from inside the bowl. There is likely a donut shaped vortex of lower pressure air inside each bowl. Higher pressure than the air moving above to bowl, but not as high pressure as static air. Also when the bowl is touching the ground the air can',t be deflected straight down. It will decend still at a much lower and much more outward angle. Thus producing a large relatively low pressure areas as you explained without the bowls. Which is why it seems to suck to the surface at first, then shoot up. The ground effect is because that vortex in the bowl gets pressurized air fed up into it from the ground as the edge airflows flow towards and converge on the point on the ground centered below the bowl, and then upward. Plus notice that three sides of each bowl faces another bowl and he has them very close. I am betting half the head on colliding airflow heads upwards, not down around the bowl. Colliding airflows have higher than static pressure so the effect he depends on does not have to correct conditions in the middle of the drone. So he loses 50% of 75% of his thrust that way. That's 37.5% immediate loss in thrust. With propellets only there is a tiny frictional surface. With impellers and bowls the frictional surfaces slowing down airflow are increased by a factor of what, 50 times? Flow over the top and inside of the bowls both contribute to slowdowns in flow. As well as the probable increased turbulence. No wonder it is so inefficient.

[@palarious]

Well, the solution to reduce weight is simply to use the 3D printed dome as the form, then use a lighter, thinner material molded to it. Vaccuum forming would be ideal, but you could also likely use something liquid applied or heat shrink.

[@delicrux]

Agreed Foam would have worked well here

[@Adalast]

I would also suspect that smoothing the surfaces of the domes and maybe doing some vortex channeling along with the impellers to tune the airspeed and where/how it flows off the edge of the dome and adjust how the airflow off the inner edges of the domes interplays with each other.

[@iz723]

Or paper maiche haha

[@KetansaCreatesArt]

You are getting the COANDA effect, but the hollow bottom sucks air up again I guess, and disturbs the Coanda capabilities. So Make enclosed upside down teardrop shapes. They will also work as legs giving higher ground clearance. I guess it will work better. Also try a single motor too 🤔

[@WestWind]

or 4 little motors (for control) on one teardrop...

[@WestWind]

@TILEN FABE well ...symmetrically? but never mind it is obsolete ...not a great idea probably to have a full teardrop bc the flow may go all the way along the bottom surface and would there produce a counter force...

[@mcdjay]

@TILEN FABE in wind tunnel tests done at our lab we recognized with the open bottom the air does in fact curl around this causing positive force on the z-axis. Our hoverboard prototypes did not work as well with a teardrop or a ball.

[@KetansaCreatesArt]

@TILEN FABE Single motor, just as a side experiment to see how it goes.

[@mcdjay]

@TILEN FABE the z axis is the vertical so correct, the lift is increased as it creates positive prussure

[@bobafete24]

You should try a Magnus effect drone!

[@leyline77]

Flight test did this with kfc buckets. Look it up on KZbin

[@Thenameisbond1]

Trent Slutzky wouldn’t that need a movement already in order for magnus forces to take effect?

[@leyline77]

@@Thenameisbond1 kzbin.info/www/bejne/gWfKloKjqJhmes0 They spun the buckets with motors, there was the motion.

[@YourAnonymousGuy]

As a Romanian, I appreciate that you spelled correctly, Coandă. Cheers!

[@CosmicSoundMDB]

You must be jocking, or you forget your romanian spelling! He never mentioned ă, and his spelling sucks for Coandăs name, and someone of his importace.

[@thatfigman3153]

este beat?

[@valevisa8429]

Te-ai trezit si tu pacala ! Cere-i adresa sa te duci sa-i pupi mana ,ca a scris numele corect.

[@jurrien75]

I think the impellers need stator vanes surrounding it. Just the impellers will spiral the air around the domes losing efficiency. Stator vanes direct it downwards and reduce turbulence

[@lakloplak]

Vacuum form thos bowls! Lighweight, fun DIy project and many more applications!

[@Atka59]

The open bottoms of the domes is allowing pressure differentiation to almost equalize, plus they act like sails. I love your work, your initiative is to be commended.

[@mihailazar2487]

FOr added efficiency I'd suggest a small skirt along the top half of the impeller (since the impeller draws air from the top, and out the sides) you could essentially put a small skirt around the top of the impeller, so the upper part of the blue sahdwich extends just a couple of centimeters outears more than the bottom half, and (this is really important), to make sure none of the air flows back up because of the high pressure, the top extending part of the sandwich has to have a small, subtle downward curvature, just to push more of the air downward

[@hamjudo]

The longer skirt you describe could make it into a sort of ducted fan. With an insane amount of work in wind tunnels or simulations someone with an insane level of dedication could get the curve of that upper skirt just right, so the air through the duct zone has the ideal cross section to flow rate ratios as the air moves through the duct. Probably not an ideal investment of time. Optimizing the dome size might be more effective, even if still in the insane zone. If you took off the bottom few centimeters of some, does the decrease in mass make up for the drop in effect.

[@AsciiSmoke]

Hi Tom. I’m guessing that the impellers are losing a lot of pressure from most of the air escaping outwards instead of following the domes. Maybe you could try some curved ducts around them to direct more of the air at the curved surface. I also have a feeling that vertical ridges on the surface of the domes would pull air more efficiently as it might reduce cross-buffeting. Would be great to see a follow-up video. 👍

[@blazerorb]

I’m sitting here wondering why you don’t just put the impellers below the domes with an impeller-sized intake hole in the top

[@Hoolahups]

@@blazerorb because that would defeat the purpose of the effect. this isnt meant to be good, its meant to be goofy

[@casanovafunkenstein5090]

It would definitely work better, but it wouldn't actually be a demonstration of the principle being explored

[@ryanhearty1143]

You should try shrouding the impellers. In my experience any time you have an impeller for any application, it’s shrouded.

[@davey2k12]

It's not a impeller if it's open he using impeller as a propeller that's the problem

[@clayton458]

@@davey2k12 I recommended putting the impeller under the bell that way its " shrouded" as long as he adds an intake above the inlet of the impeller.

[@schneider1492]

@@clayton458 ya, but that wouldn't be using the coanda effect.

[@charlie2b-d335]

The impellers are only effective when encased, the propellers work better but they need a shroud so air doesn't escape on the sides, think about a cooling fan on a car for example the shroud directs the air towards the radiator so doesn't get wasted on the sides. the same principle will apply on this experiment, also the single piece was better in my opinion due to the less weight than the multiple pieces, a single piece with shroud and bracket could B 3d printed in 1 piece all you need is just the screws to mount the electric motors, aluminum frame can help on reducing weight so the batteries can stay on the drone

[@Riker626]

The impeller that broke was probably producing more air flow, thus pressure and broke. Re-print that impeller with thicker walls for the additional force, should help.

[@excitedbox5705]

No, it was spinning fast enough that the outward force made it rip off.

[@ohctascooby2]

The one that broke had no upper support and as centrifugal forces built the top started to be pulled outward until it snapped at the base.

[@YCbCr]

The one that fried the motor was probably the best though, downsizing it a bit might have helped.

[@raadaurizeichnerderkonverg973]

@@excitedbox5705 This is why most impeller designs are inefficient in air because the static pressure of the medium (here air) is quite to low. But Impellers are highly efficient in water.

[@Build_the_Future]

Can you test a ducted propeller drone vs a regular unducted propeller? Will it be more efficient even with the extra weight?

[@peterzingler6221]

It will and will not be. The ducts may increase thrust but then the airflow is also more turbulent and the overall performance sucks. There's a reason you don't see that concept used

[@kal9001]

I've seen tests done with ducted fans used for hovering, and they are pretty poor. Though a stationary hover is rather good, once you start moving laterally is causes the airflow the become asymmetrical causing a significant decrease in performance and asymmetric thrust which has two effects. 1, to reduce overall thrust, and 2, applies thrust in the opposite direction to the one you're trying to move in, so the aircraft will essentially fight you all the way to the ground if you try and make it move quickly.

[@trevorschrock8259]

@@peterzingler6221 How about ducted airflow through smaller tubes for laminar flow? I know that works well for liquids, but I don't know about air.

[@peterzingler6221]

@@trevorschrock8259 same thing there to much loss. Modern propeller are as efficient as it will get. If you want more efficiency go for less blades aka a helicopter. That's also why most military drones are helicopters not quadcopters

[@frankenfoamy]

Many years ago when this idea was first tested for drones, a shroud around the prop increased efficiency ( and safety) to the point of always including it in subsequent test beds.

[@tudoralexandruienulescu2214]

As a Romanian, I am very proud of you for using the "ă" corectly. :D

[@niallpearce8043]

Make the domes out of a helium filled bag. Airship lift with added drone power.

[@69fox]

Lol

[@selsuru]

I was thinking the same thing but with hydrogen

[@69fox]

Guys, that's not how it works. This little volume of gas won't help at all. I don't really see the point in even making something alike with the thing in the video, but that's just ridiculous.

[@0012erick]

@@69fox Disagreed, shaving grams of a drone is what people do for performance..

[@69fox]

@@0012erick, no. Saving weight can help, but adding that much new parts and complicating it with gas filling is pointless. If you want performance - don't even do this lol, there are much more practical things to do.

[@MacceJohansson]

How about trying out so called chevrons at the bottom of the bowls, much like how they do it at the rear part of modern jet engines? I think that might prevent the flow of air to go into the bowls, directing it more straight downwards. As always, thanks for the video!

[@matthewconnor5483]

Chevrons on turbofan engines have more to do with controlling the way the airflow leaving the engine meets the air flowing outside the engine and the noise created as the result of that high velocity air flow meeting the much slower air outside the engine. This matters a lot when trying to reduce the noise at take off when the aircraft is at high power but lower air speed.

[@matthewconnor5483]

@Klippy Klop www.nasa.gov/topics/aeronautics/features/bridges_chevron_events.html

[@MacceJohansson]

@Klippy Klop but you are not being very polite in you language! 😒

[@sevengrapes1257]

The centrifugal impellers you are using produce lower air flow at higher pressures. Axial flow impellers do the opposite. I believe air volume is of more importance to you than air pressure. Ask fan manufacturers for advice.

[@InsufficientGravitas]

That explains why the propellers generated more force the faster they lifted

[@fajile5109]

14:38 i think thats right since the air inside the dome would not be moving much at all itd be realitvly low pressure compared to the edge kind of like that dome is a cookie cutter.

[@ogenkidesu3778]

This was an interesting phenomenon to learn. It seems like the coanda effect is more of a condition that impedes aerodynamic performance than a property which enhances or lends utility to. Your video was enlightening and entertaining, thanks for educating!

[@MrPzyt]

In 70' I had book about building hovercrafts and hovercraft models. If memory serves coanda effect hovercraft was given entire chapter.

[@ArsathSally]

Dril holes on the domes and cover them with some sort of a membrane to reduce weight.

[@buttonasas]

I predict they would be blown out from inside and, therefore, slightly deform the dome, which would decrease the efficiency.

[@ArsathSally]

@@buttonasas wouldn't it depend on how well you glue it?

[@TURBOCOW9000]

or just make them out of 2L soda bottle tops

[@travispetler6989]

springed pressure release valves, build interior pressure, reduce weight displacement, then release as interior pressure overflows

[@petemiller519]

Good video Tom. Your initial thrust tests basically predicted the outcome. I imagine the Coanda effect loses efficiency since there must be an outward thrust component, and not all of the thrust is directed downwards as it the case with a propeller. You might want to revisit this with redesigning the bowls into a similar shape as the Dyson fan, which is based on the same principle. Cheers from Canada.

[@davidhorner590]

Encase the impeller with a covering bell so the wasted airflow is directed along with the drawn air.

[@dennisstander9349]

I agree 100% with this. I rate you could very possibly achieve desireable lift with that relatively easy mod.

[@airgliderz]

Adds weight.

[@AutitsicDysexlia]

I was thinking the same, but only because with the Impeller, it's basically half a turbo that is wasting most of its power due to a lack of "plumbing" to channel it.

[@AutitsicDysexlia]

It can't just cover the impeller though, it has to cover the whole thing and serve as sort of a channel... the only real problem with this... is that it isn't an illustration of the intended effect... it's just a way of making the thing produce thrust instead of wasting air power.

[@vishva8kumara]

One big problem in using in-runners in this design is that the motors do not get cooled by the wind/thrust it produces.

[@LarryH54]

I notice you only built the top half of the coanda device. Where's the lower airflow guide?

[@OdeeOz]

*_BING!_*

[@jackasshomey]

im pretty sure the whole thing would work a whole lot better if there was a larger dome shell ontop of the existing domes that way there would be close to 0 airflow loss

[@lloydpimm1271]

@@jackasshomey that is same as the curtain/skirt of a hovercraft .

[@jackasshomey]

@@lloydpimm1271 yep :D and that's why it would probably work a lot better lol the quad copter orientation is actually a great idea cause you would be able to control the movement on all axis by lowering or raising a single fans speed

[@DrNA142]

i think you can increase efficiency by inverting the domes, make them rounded cones, like funnels, and make the each impeller blow horizontally on the wider lip of the funnel into it's center. i'll be less odd looking for sure, but i believe it'll work better, and still use(at least partially) the coanda effect.

[@karlmahlmann]

Your videos are a ton of fun for this old engineer to watch.

[@RKroese]

@Lambda Music whatever gave you that idea... 🧐

[@MrExo_3D]

if bottom was solid. vs a bowl shape, wonder how this would change the ground effects

[@themanthemyth9633]

It wouldn't change it in any significant way

[@6sfullrcbycarlscustoms473]

The bowl could be sought all the way around but still be hollow in the middle so it wouldn’t weigh that much more

[@notchs0son]

I mean you may have less lift because there’s less space for air to be in low pressure under the bowl

[@jackherrod2294]

Or a cone shape?

[@tmtigd]

@@notchs0sonyou want the low pressure to be on the top. If it’s on the bottom the pressure is pushing down.

[@MrTheblackopsdude]

I have a suggestion, most likely won't help, but would a ducted impeller would better than unducted ones?

[@suppermud4017]

Probably

[@FireTome]

@@suppermud4017 Or perhaps he could use propellors that fire sideways.

[@yetidynamics]

ducted fans work great but require extreme precision to work correctly, if your tolerances are loose, you end up making them less efficient

[@uquarosh]

A bold attempt to prove a complicated and involved theory. This is real science and we will be watching to see how it evolves.

[@adiliraliyev5882]

and you can sand it too to be smoother or make some geometric shapes to increase the air flow.

[@robson668]

You could have printed this dome upside down, you wouldn't need supports this way ;-)

[@officer_baitlyn]

than the overhang problem wouldve been at the bottom it wasnt jus the large flat surface that posed the problem

[@milkhbox]

@@officer_baitlyn There wouldnt be any overhang if printed upside down. It would be directly touching the bed at that point.

[@mikehawk4517]

True, but he also stated he didn't want the layers to be perpendicular to the airflow. So, he would probably end up doing what he did anyway

[@milkhbox]

@@mikehawk4517 perpendicular layers would greatly increase drag, but it would cut down on assembly time by a lot. Though, given how inefficient this setup already is, it definitely needs every helping hand it can get, so his setup does make more sense.

[@mikehawk4517]

@@milkhbox Assembly time isn't even a factor here. He's not planning to mass produce this any time soon.

[@ghassanm3]

Excellent video mate... I love the fact that you built it and tested it... well done!

[@sebastianene7657]

Those motors are really doing their best ! Awesome project, thanks for the video & sharing this

[@mattle3]

Maybe try to sand the domes and print them in one piece upside down

[@kadmow]

Or print one as a mould, then vacuform (very little equipment needed: vacuum, heater and vac-box/former) all the lightweight domes required.

[@mikeweber236]

@@kadmow 06tn ..nģ3z26 Ć6

[@mattle3]

@@mikeweber236 ?

[@kadmow]

@@mattle3 : Thanks for that info.. Very useful.

[@mattle3]

@@kadmow what

[@ironmike4843]

Things I would do to make it fly better with Impellers: 1) allow air to cool the motors 2) Add aerofoils to impeller shapes 3) print bowls upside down 4) add fins to bowls 5) smaller diameter bowls 6) six motors and bowls

[@rodrigoc.goncalves2009]

Just out of curiosity, what difference would the fins do?

[@almarma]

@@rodrigoc.goncalves2009 I suppose it's to avoid turbulences so the air flows more straight downwards.

[@xXTepicwinTXx]

Theres probably some mathematical optimization that can be done to help make the shape of the bowl more effective.

[@mikecrim5292]

How about big foam propellers that rotate slower but generate same or more thrust.

[@johnkrappweis7367]

Could you eliminate the drag effect by getting rid of the bowls and using a ball or teardrop shape?

[@senatorjosephmccarthy2720]

Fan...tastic idea.

[@simonbradford3422]

Tom Stanton your a shinning example for all young engineers and tutors out there, your inspirational, passionate and intelligent with a simplistic and well spoken delivery in your explanations. You will go very far in your professional life and career. Well done and keep up the great work.

[@deangermeten5629]

You need much faster air-flow for the coanda effect to work properly for you.

[@benforman5284]

Awesome project and great job! I think you’re on to something and I believe you could get it to work. I have a few ideas, as I see many others have ideas too. 1: Majority of the lift would come from the top surface. The impeller may be removing a large section of that vertical pressure difference. You can still use an impeller, just switch it to the axial type that pulls in air from the outer diameter and pushes it down the middle. Mount it a little higher, like your traditional prop setup, and you’re golden 👍🏼 Also, this type of impeller will suck in more air. 2: Ridges on the surface of the bowl may not be a bad thing, rather near the outer edges. You’ll have to research this for the full explanation but inducing turbulent flow around the area where the laminar flow starts to separate from the surface actually helps keep the flow against the surface slightly longer, which really helps at low speeds. Examples are gulf ball dimples and vortex generated on the front edge of airplane wings. Now, ridges from printing may not be most effective, but maybe you could add tiny vortex generators or dimples wherever the flow breaks away at LOW throttle. 3: Close proximity of the domes may be effecting each other, let alone the impellers directing air towards each other. Also, horizontal movement, or winds, will effect the flow on the domes which is your lift. Not sure if this is a solution, but maybe add walls to separate four sections 🤔 maybe each dome could be inside cylindrical tubes. I’m thinking like the Parrot drones that have foam wall attachments. 4: THE DOMES COULD ALSO SPIN! This is more of a fun experiment bc I don’t really know if there would be any benefit besides acting like 4 gyroscopes lol

[@flazerrazer2992]

I may be confused at way the way you mentioned it but those vortexs on the wing tips are actually a bad thing

[@ryanlandry8214]

Hey Tom, awesome project! I agree with you about having some turbulent flow going under the dome because you have a radius and a rounded lip at the bottom so you end up with ground effect until the velocity of air can shear away. This design is good for a hovercraft. You need to have the dome wall stop at 90 degrees or slightly more (with respect to the ground) and leave a sharp edge to have a more laminar airflow that shears straight off the dome. Also some fins may help direct the air. Think of a diffuser on a race car. At the moment you have a rounded edge like some juice bottles where you have the juice run down the bottle onto your counter top if you don't pour fast enough. Also vacuum formed polycarbonate would probably work well for the dome. I'm sure it would be lighter.👍

[@alphagt62]

I was thinking the same, you could just about cut the weight of the domes in half by removing the lower half. Just as you said, beyond 90 degrees. I also imagine a plenum around the impellers would help keep the air moving closer to the top edge of the dome, but, it would also add weight, so I don’t know if it would help more than it would weigh?

[@garylanders1470]

Have you thought of making the dome shapes into lightweight helium balloons? You could mount the motors above the domes from arched outriggers from the body of the drone.

[@Hoffmanpack]

Neat, could upscale that and make large platforms with solar panels!

[@victorpolier8977]

This could be turned into a marine drone with the big red domes working as floating platforms.Would love to see it

[@oldsteempunk6728]

That is a good idea. I was thinking towards the end it was a bit pointless just having the domes essentially blocking the propeller airflow (apart from the novelty of it), but seems it could be used to enable a drone to land on water quite effectively. Tom?

[@Nuovoswiss]

I like these sort of videos on obscure propulsion/lift methods, even if they aren't totally practical. It would be neat to see something based on a tesla turbine, or perhaps a tesla-valved pulsejet.

[@QuantumFluxable]

check out Peter Sripol's "RC KFC bucket aeroplane" then, using the magnus effect :P

[@ryanspence5831]

MAKE AN EKRANOPLAN!!! Basically ground effect to the max

[@DriftTrainis2awesome]

Ryan Spence his friend, Project Air, did(he has vids on his channel Project Air)

[@SpecialEDy]

People get confused Bernoulli's principle. All vehicles: quadcopters, airplanes, boats, cars, rockets, submarines, anything which moves, follow Newton's Third Law. A wing generates life because it pushes air downwards, Bernoulli's principle only describes the mechanism in which reactionary air mass is pushed down by the wing. These Coanda effect domes would be no different. They are moving a mass of air downwards equally and opposite to the lift on the quadcopter.

[@Allan_aka_RocKITEman]

@Tom Stanton >>> IF you had tried this but been unsuccessful, you could have called it _The NOanda Effect._ {I will see myself out now...😊}

[@senatorjosephmccarthy2720]

I not only agree, I bgree.

[@GeofreySanders]

Coandǒn't

[@DolganoFF]

Let me rephrase the outcome of this experiment: Attaching salad bowls under the quadcopter propellers, makes the drone much worse flyer. Am I good?

[@PhilJonesIII]

Before or after eating the salad?

[@MihaiAndreiStanimir]

Awesome explanation! One bit of help those not speaking Romanian, Cuanda is pronounced "cwanduh" :)

[@rowaba]

Hey Tom. If the air pressure underneath is bouying up the craft then the red domes need not be so parabolic shaped. Flatten them out like a wing and the air flow above should drop the pressure and make your Corriander lol effect

[@unionse7en]

place the motors on the top side, so they receive some cooling airflow....

[@rodmills4071]

Love the amount of time you put in just for the what if factor. So what if it didn't work 100 percent...you won't die wondering. Good job.🤣😂😁😀😎

[@tolebelon]

You need something to turn the airflow laminar before leaving the funnel so you can get more of that classic wind tunnel smoke lines.

[@sandienochs6132]

I have always respected the work of Mr. Hiller, you are on the right path.

[@justinsmith2363]

3:52 "layer lines perpendicular to the airflow". I don't think this will do any harm. Frisbees (also using Coanda effect) do this on purpose. They have a ring of ridges on the top surface near the rim. Their purpose is mostly to enhance stability/consistency by forcing the transition from laminar flow to turbulent flow at a predictable point. The airflow over a frisbee is different, so the air flows over the ridges twice, and the ridges aren't truly perpendicular to the airflow everywhere, as they would be on the dome. But they are, by design, deliberately perpendicular to the airflow. Frisbees spurn laminar flow, but they still fly pretty well. BTW, frisbees and spinning balls also exhibit a different effect, the Magnus Effect, which is actually enhanced by surface roughness.

[@mishaparem]

One this that is significantly different between a frisbee and the domes being used here, is the dirction of travel. I challenge you to throw a frisbee with the top flat surface towards the direcyion of travel. You wont get very far. It's like trying to rip a frisbee off the water directly upwards - you'll just create a vaccum under the frisbee, and it will be much more difficult than to pick it up from one side and tilt it over first, to let air in.

[@ljy82]

amazing....I love experiments like this. It is very enjoyable to me. To see how others minds do creativity that helps others learn and expand their own.

[@nihalsuri4543]

I learnt so much and also had a blast watching the video. Great job.

[@rickt1866]

i like this idea for like a cycle / hover cycle. the blades on ones I have seen don't look safe but this looks like a better option and you don't need to get much height for a good hover bike/car?

[@IamGrief887]

What if you double the domes (a dome inside a dome), and direct the airflow between the domes in order to compress the air and create greater thrust?

[@JWH3]

This is the aerodynamic lift version of a Rube Goldberg device. Slightly pointless yet totally awesome :) great video!

[@imwacc0834]

He did better than the VZ-9 Avrocar kzbin.info/www/bejne/gJaripKZZpiajKM

[@Lumencraft-]

Good demonstration. I like how you jumped right into it at the beginning.

[@mrbruce5666]

The first coanda effect drone pulled the air from underneath which hit inverted cone above deflecting air down over outside surface.

[@cipriannecsutu]

I was reading an interview with Coandă, in the original romanian language, he was talking about building models when he was younger, but with persistence and playfulness he was able to achieve so much more.

[@MidnightMarrow]

Ground effect will be greatly increased with all that extra surface area. ;p Also I am pretty sure impellers need some sort of shroud to maximize their potential power output. I think they lose a lot of pressure being exposed.

[@woodrunner51]

why not use them impellers to make a ground effect vehicle :)

[@motoklay]

Did you balance the impellers? If you didn't you may have lost a lot of energy due to vibration.

[@Skyfighter64]

I don't know if you've followed up on this drone test in a later video, but I think I do see one distinct flaw in your understanding of the "Coanda effect" (I've always known of it as part of the Bernoulli principle), is that the movement of the fluid will generally not be influenced at an angle over 90 degrees from initial flow. Angular momentum can be a pain in the ash like that. If I were to suggest an alteration that might increase the efficiency of your design, I would probably have cut off the bottom quarter section of each dome, as they are extra weight for very little increased effect, and I would probably have made a "vent" around each impeller to stabilize the airflow slightly, and just make it bond better to the surface of the domes. The last thing you could probably do to increase the efficiency of the domes is to use Acetone vapors (depending on the material used of course) to smooth out the surfaces of the printed plastics. At least, that's my understanding of the principles involved. Still a neat video to watch, and concept to consider.

[@jukkapekkaylitalo]

Y i think attack angle of coandas curvature may help. Maybe it just needs more low pressure zones.

[@tonyvandyke7588]

Why not use two domes. An outer and inner dome with the space between being a control space for the air flow.

[@jordanoliver1810]

That would stop the higher pressure outside air from rushing to the low pressure area which is creating the thrust

[@tonyvandyke7588]

By inverting the impeller and placing it in the top of the dome and another impeller on the outside top of the dome

[@tonyvandyke7588]

Create low pressure outside and increase pressure inside.

[@tonyvandyke7588]

With thrust as a byproduct

[@0012erick]

You are almost doubling the weight with two domes.

[@BrianRamseysg01]

If those domes were made from foam say 90% lighter it could work a thousand times better well done!

[@bigofano1794]

I am curious if a flared lip at the base, imitating a bell curve might be more effective? All ways enjoy your projects and curiosity.

[@mykahmoe1420]

I think it might act like a foot plate and draw the air that's in the bowl around the lip and throw some air up. I could very well be wrong but that's my guess