Coanda Effect Hovercraft

[@koosnaamloos4291]

This channel basically shows the trade-off between practicality and ingenuity In this case: The trade-off between a good and a fun lawnmower

[@Erdroy1]

Hovercraft lawnmower? Seems fine to me. Extremely safe. I NEED THIS lul

[@LordDragox412]

He did not make a good hovercraft, but he did craft a hoover/vacuum cleaner for leaves :D

[@acered1651]

flashback to honey i shrunk the kids RC lawnmower scene

[@xdragon2k]

Next Video: Lawnmowing Hovercraft.

[@jchan3358]

@@Erdroy1 A lawn mower that lifts off the ground...what can possibly go wrong?

[@annahilation]

So nobody’s going to mention how amazing his lawn is

[@Skullwalker]

Probably had to keep it down for it to work😁😎

[@Skullwalker]

Definitely noticed the stripes though 😁🍻

[@memesfromdeepspace1075]

@@Skullwalker i thought ITS my screen broken but nope ITS just the grass color

[@mackdlite5900]

Fit for the Queen's corgis!

[@OMEGATEAM473]

He c&c s it.

[@JoelCreates]

Welcome back to today's episode of: "Unconvential Lift"

[@SirBoden]

Efficiency is overrated

[@soundslave]

Next time we look at boob-tape

[@angrymario8259]

@@SirBoden my German heart can't allow this

[@emadharoon1656]

JOEL You’re here too 😂❤️

[@logmeindangit]

Did you mean "Unconventional"?

[@olusanyatodd4083]

I dont know if anyone else mentioned it but this had one of the best sponsored segment formats.. I didnt feel the need to skip cause I could watch him work on the hovercraft.. Nice

[@bwoods311]

This is the most times I’ve ever heard the words ‘coanda effect’ in one day, crushing the previous record of 0. Love your projects!

[@AsbestosMuffins]

"Here's how to make a very inefficient but physically interesting hovercraft!"

[@BienestarMutuo]

For second time, this man could be the king of inefficiency.

[@MrAlipatik]

lmao

[@squeakybunny2776]

@Elijah the only cars that get *pulled* forward are broken cars... Cars *push* themselves forward

[@squeakybunny2776]

@Elijah so your second comment already was quite toxic and now you also show how stubborn you are and can't take it that you were wrong... Your personality sucks hard mate

[@HadoukanFire]

Sometimes science is testing a hypothesis

[@simloverify]

You should water proof the electronics, put some foam in the sides for flotation then try to take it to a lake

[@JohnLGalt_1]

In other words, what you've built is a Coanda effect leaf gatherer.

[@awhahoo]

No longer have to rake

[@troychildress5540]

I can have fun driving my rc but doing a chore Humm I shul make this

[@kiwibob223]

You need mount a gun so you can bullseye any womp-rats you spot

[@Caramelhorse1]

If he markets these as garden roombas he'll be a millionaire in no time!

[@guenbarnes1659]

I feel a huge advantage over conventional hovercrafts is that you've succeeded in freeing up the airspace inside the fucilage which can now be used for people or packages etc.....Also, as wonderfully demonstrated as your presentation is I feel it would be a great addition to have a smoke or some such in slow mo to truly impress upon the viewer the Coanda effect....great stuff all around, pleasure to watch...

[@MrRonny6]

Considering how many leaves I have to rake every year, that little side effect makes this hovercraft very appealing!

[@dimitar4y]

have fun while you clean :D

[@AtomicShrimp]

This was really interesting - it would be good to see it in action with some small smoke sources attached, to trace the airflow

[@tyronekim3506]

I agree. This model demonstration showed that it's better to use unobstructed flow thrust for lifting than to use flow effect due to Coanda.

[@sebastiangeorger5791]

Hey I love your videos Atomic Shrimp

[@Mr_Lesbian]

wow this channel really attracts KZbinrs I watch huh? Also yeah that would be super cool.

[@nocturn9x]

What a weird crossover indeed

[@DannySullivanMusic]

i agree! precisely right!

[@_tyrannus]

The efficiency of this setup puts tears to my eyes, but it's a very interesting experiment nonetheless. I'm glad to see you use foam as well, it can't be praised enough for small scale lightweight construction. Please keep doing ground effect vehicles! I would really love to see you attempt a wing-in-ground craft in the spirit of the Orlyonok: a long fuselage with stubby wings, a high T tail with the main propeller blowing onto the control surfaces, and a pair of front-mounted jets blowing air under the wings for takeoff. You definitely have the skills needed to address the vertical stability issue, using some kind of distance sensor and a PID + filters to keep altitude within the tight stability envelope.

[@rizalardiansyah4486]

Or perhaps a simple trim control for the lift motors for a start?

[@atomicsmith]

Totally agree about WIG. I find that subject very interesting. Also probably significantly more efficient than this arrangement...

[@bipolatelly9806]

I praised some foam and it turned red. Never again.... (unless I need red foam.) It shat me to tears.

[@KuraIthys]

The problem with the ground effect for these kinds of small-scale experiments is that the practical 'hover' height varies in relation to the vehicle's scale. This is why even a 100 metre long hovercraft is using a rubber skirt to increase the ground clearance. Aside from serious stability problems with the ekranoplan concept, there's also just the sheer issue of scale; Normally, vehicle technologies are developed at a small scale and then gradually made bigger. But the underlying physics of a Ground Effect Vehicle is such that small vehicles are VASTLY less practical than larger ones. A 600 metre long cruise ship size GEV would function so much better than even a 100 metre long version that it's almost incomparable... Yet it's self-evidently impractical to jump straight to building a 600 metre long vehicle as a test. And when you get down to the scale of even a car, you're already dealing with effective 'hover' heights (if you aren't using the rubber skirt thing to artificially increase it) of a few cm... Something the size of a typical small scale model hovers at such a low ground clearance that even a moderately uneven indoor flooring surface would be difficult to deal with...

[@_tyrannus]

@@KuraIthys I know about these constraints. If you ask me I'd love to see big ekranoplans being developed as a replacement to airliners and/or cargo ships! The scale at which you can make them would likely make them good candidates for nuclear thermal propulsion, as you would have plenty mass and space for a submarine-type reactor + shielding. Yeah you could also make cruise ships, but those should really disappear at some point if we're serious about pollution. As for the small scale, there are smaller ground effect vehicles being sold that aren't bigger than a small boat, and they definitely only stay aloft through pilot input. You also only need a boat licence to operate them but that's another story. Put a microcontroller on the job with Tom's code, and I think (at least I hope) stability shouldn't be too much of an issue as long as the model's actuators react fast enough, even at an even smaller scale.

[@robustix4530]

"Ive covered all the electronics in packing tape, so they should be waterproof" Famous last words

[@DannySullivanMusic]

rofl awesome comment

[@LordJazzly]

This is absolutely fantastic. Sometimes, it is less interesting to know if a thing will work _well,_ than it is to dicover whether or not it will work _at all._ Edit: Never mind, I'm eating my words now; it's a hovercraft that can do jumps. That's the coolest thing I've seen at least all week.

[@fenderstratguy]

Appreciate how you include your failures and document the incremental progress that leads to success

[@morkovija]

Perfect ad segway. I dont mind listening about the sponsor (that is honestly all over YT already) while watching you work

[@edwardatnardellaca]

I was also incredibly impressed with the sponsorship segment, possibly the most palatable one ever seen!

[@TIICProductions]

This is the first ad I haven't skipped over in ages! @audible should take note!

[@malfattio2894]

It also helped having something interesting to look at but not too important in the ackground

[@richbuilds_com]

Definitely how to do ads without turning off your audience.

[@Keex11]

@@richbuilds_com *some of your audience. I don't like it.

[@SocksWithSandals]

13:47 was the money shot for me: That slo-mo jump over the gravel path had my inner eight year old imagining Luke Skywalker skipping over dry river beds on Tattooine.

[@SecularGeek]

I was seeing landspeeders too!

[@joonasfi]

Yeah, that was totally badass!

[@thejokestersquad3686]

@_ David _ are you refering to your comment there?

[@thejokestersquad3686]

Ah, a child I see, well then, there's no point for my further precense here

[@hugostiglitz6914]

It's difficult to see how much is the coanda effect and how much is the fact that you're using lift propellers in the first place. You could figure this out by mounting the lift and thrust motors on a flat plate with the same plan area as the coanda hull and see how much lift you get.

[@dklouwens7559]

The probs actually create downwards thrust. So the coanda effect is clearly visible

[@tananam9782]

@@dklouwens7559 How is this "clear?" Please be more precise.

[@tananam9782]

@@BondiAV Perhaps a better understanding of the coanda effect may be seen in directional effect, rather than lift. That is, can we use coanda to direct a vessel diverting downward thrust into horizontal thrust? Hmm... How may we be able to differentiate the effect of coanda from the simple Newtonian redirection of thrust? I'm no aeronautical engineer. It's hard to imagine that someone hasn't already thought of all this. Interesting to ponder, nonetheless.

[@benjaminhackett8896]

@@dklouwens7559 Uuh, if the propellers were producing downwards thrust, the propellers would have to be pushing air upwards and away from the hovercraft.

[@acblaze3116]

Exactly! I was just about to comment the same thing

[@paulo8001]

Cover the underneath so it doesnt collect detritus, give it wings with aelerons at the back and put the forward thrust props at the front. This could really take off.

[@jamesshriver4822]

Absolutely correct!

[@ronjoe6292]

It doesn't matter which side the thrust props go, it's completely equivalent. It's like the pendulum rocket fallacy.

[@tapuout101]

Maybe covering the bottom will make it more efficient?

[@whaaaaaaap]

I need to see it

[@TlalocTemporal]

​@@ronjoe6292-- Since the thrust props aren't aligned to the center of mass, they will apply a different moment. Rear mounted is probably better here though, better pitching up than pitching down.

[@shlywa660]

The out takes are a good show of the the ruggedness of your project and building skills. The advantage to your design is shown a bit when it travels over a drop off and maintains lift instead of losing all the air out of the traditional envelope. Looks like a fun project. Keep up the good work!

[@rizalardiansyah4486]

Wow, i do find this very interesting idea, but there's two things i want to point out : First, perhaps you should have kept using impeller instead of propeller as it seems the propeller created too much lift that the coánda effect plays an insignificant role in lifting the hover craft. Second, to prove whether there is coánda effect in the first place, you can use the fog generator like from last upload. I hope this could help the development. Thanks for sharing this project to us Tom, can't wait to see your next upload.

[@EdwinSteiner]

Indeed. A comparison to a similar build with the foam body replaced by a flat sheet of the same footprint and weight would also be interesting to see how much the effect contributes.

[@EdwinSteiner]

P.S.: Note, however, that the downward momentum imparted on the air by the propeller is transferred back to the hovercraft when the air is redirected to the horizontal flow, so at least that should not contribute to an overall lifting force.

[@1Hippo]

@@EdwinSteiner Correct, but not the complete momentum is transferred back, otherwise there would be zero left (no horizontal flow at all). You would need air speed measurements before and after the redirection, i assume the difference is only a small fraction.

[@soeveth]

@@EdwinSteiner I believe there was an episode of Mythbusters that used a fan to blow air against a sail and it did provide enough thrust to move the boat forward slowly. While not exactly the same, i believe its the same principle.

[@soeveth]

@Desmond Bagley yes I do mean that, it didnt make sence to them as well as all force should come out equal. But they were able to move the boat slowly against the wind if I recall, But it was very slow like 1 or 2 km/h. kzbin.info/www/bejne/q3y7foewgraKoNE

[@FATMAN_tactical]

Its as a yard vacuum that even the kids will love. Comes with free pair of shin guards!

[@2010ngojo]

When you made a roomba to collect all the leaves for the autumn season.

[@uggranpops8442]

*outdoor roomba

[@uggranpops8442]

@Wyatt Watling a roomba I'd buy

[@erikpatrone1077]

It's really interesting, but I think that the coanda effect isn't enough to lift the hovercraft. You have used standard propellants that creates a low pressure area above theme and this is probably what have lifted the hovercraft. This is the same principle that make helicopter fly.

[@andrewsparkinson1566]

That makes sense Erik, i think your on to it.

[@XXX3RX0]

Okay, so, I was about to write a long essay on why this was wrong, but I caught myself misunderstanding what you wrote. I think what you're talking about is Bernoulli's Principle which also applies to other crafts, such as airplanes. While this is technically true for the propeller wings and commonly accepted in aerodynamics, it does not tell the whole story. While the Coanda effect isn't an efficient way to create lift, it does, in fact, direct the flow of air downward which (using newton's third law of motion) dictates that an opposite force would lift the craft upwards. Now, why I disagree with Bernoulli's principle being the biggest contributor to the lift in this instance is because if the shape of the body had been more flat, the downwards airflow would be solely pushing down on the body, causing an equilibrium of forces. Although, I'm not claiming that I'm more correct than you. Aerodynamics is still a hotly discussed topic. It works. We just don't know exactly how it works yet.

[@ionutalex7347]

i would like some numbers.... i don't see any numbers anywhere

[@ColinDH12345]

@@XXX3RX0 Its a misconception that Bernoulli's principle is the biggest contributor to wing (rotor) lift. Its a myth that gets replayed all the time. If it were then flat wing balsa planes wouldn't fly. Also, many aircraft can fly upside down and that's not explain by Coanda or Bernoulli's principle. Its the angle of attack reaction that is the main lift generator in aircraft. Just to clarify a point.

[@catroarb]

Exactly, the vertical helicopter positioned propellers create lift either bcs even if the base is big, they might still be pushing enough air down to create lift or as someone said, bcs of the blade's shape (if those are wing like)... The way to find how much trust those are adding would be having a spring or some kind of sensor that tells how much those propellers pull from the body and subtract the entropy created by the blades pushing air gainst the body which just goes to vibration etc.. My prwdiction judging by the low motion vid showing how the hubber flies straight out of Ramos is that the C effect is almost neglectible, other wise the body would immediate ly fall after leaving ramo, since the C effect would have no ground to push on

[@davidtomasetti8520]

File this one under “just because you can doesn’t mean you should”.. I do love the creativity he brings to his projects.

[@Novur]

Could be a fun take on a backyard Roomba It's clear that the Coanda effect is functioning to create a pressure differential great enough to suck up leaves, but I wonder how much of the lift is Coanda, and how much is those massive props just pulling the whole thing straight upward

[@toxaq]

Novur needs to make a square sided version to compare.

[@MrKakaofreak]

@@toxaq exactly what I thought, would be interesting

[@wesmatchett615]

I don't think that will work at all. The downward trust of the props is hitting the craft body, cancelling out any lift. For the same reason, you can’t put a fan on a sailboat to generate thrust.

[@bdhost07]

I bet most of the lift is coming from the props. The fan/sailboat comparison doesn't really apply here.

[@AKULA689]

I saw that as well, I thought the design would create a stronger vacuum and pull it down. Maybe a small vent hole just under props to either vent any suction or possibly push some thrust down into the space!

[@strangelee4400]

I can't imagine the coanda effect having a noticeable difference to be honest. Mount the props vertically and see if there is any downward thrust due to the coanda effect.

[@strangelee4400]

@@mcgherkinstudios That was what i was thinking. In the configuration as it is now it's just a fat inefficient helicopter.

[@nialltracey2599]

@@mcgherkinstudios The point of the coanda effect isn't about pressurising the air below, it's about generating lift along the curved surface. Tom took the additional step of trying to pressurise by extending the curve. However, this means he now has a downward facing curve, so if the airflow is extending that far, he's actually generating negative lift that's partially counteracting the upwards lift he was shouting for with the upwards-facing part of the curve.

[@janpul1590]

@@strangelee4400 yeah, thought that too

[@SeraphX2]

@mcgherkinstudios I'm no physicist so I'm just pulling shit out of my ass, but the props are smaller than the surface area of the vehicle. This means the force it generates is pushed directly against the surface that it's trying to lift (until the low pressure is sufficient enough to cause the Coanda Effect to take over). kzbin.info/www/bejne/hGGseKWJn8h1kNU According to this video, when a vehicle (small drone) generates it's downward lift force, the weight on the scale does not change because the downward force from the drone is enough to make up for its own weight that was present when resting on the bottom of the container it is in. So, instead of going to -21 grams, it stays at 0 because the force necessary to lift it is being pressed against the container. Is this not something like what would be happening here, but since the two items are connected, it's creating it's own negating force? I'm more interested in how to prove what is causing the lift effect. Are the props overcoming the weight or is the air from the props creating a low pressure around the surface of the vehicle, causing lift? I am also curious (not knowing anything about this stuff) would the altitude of the vehicle change if the props were creating the lift directly instead of the Coanda Effect? I mean, if the props are generating the lift, sudden altitude change shouldn't really matter, should it? A helicopter doesn’t suddenly plunge toward the ground after passing over a mountain. When the vehicle jumped the gravel walkway or left the elevated, bricked area, it immediately dropped. Does this indicate that the Coanda Effect is in place (since proximity to the ground is, I'm assuming, important for this effect based on the type of vehicle) or that changes in air density matter with such small props even at a few inches?

[@manuel290597]

@@SeraphX2 Nice

[@integza]

It's really cool how you took a physics effect and applied it in such a creative way on a real project . As always was a pleasure learning with you Tom :D

[@TinCanToNA]

Love it. You can probably improve the balance and reduce its tendency to tip over by suspending the batteries and other weight lower inside the shell to reduce its cg. A wire mesh may be necessary to prevent leaf inclusion, although that will certainly reduce efficiency and might cause clogging.

[@japhalpha]

1 thing I've seen repeatedly, in your comments, is how impressive you are making inefficient systems more efficient, or how dedicated you are. I think it's rather important to have someone like you. It's entertaining for us, certainly fun for you, and wonderful to watch someone testing different hypothesis. Keep up the good work

[@marcoronzani7197]

Man, i have a project for you: An EKRANOPLAN (ground effect aircraft, originally a USSR project) !!!

[@GruntW0rk]

If you don't understand how the EKRANOPLAN and ground effect works all you imagine is it going nose in and being more or less EXPLODED when traveling 300+ mph on water. Jet boats for example. Shit goes wrong and it becomes confetti. Using ground effect means if it loses speed it falls back into the water very controller. Like when a Helicopter auto-rotates. Tl;Dr I agree.

[@fuckYTIDontWantToUseMyRealName]

Early research was actually American: en.m.wikipedia.org/wiki/Ground-effect_vehicle#History

[@hyrumsolo3203]

It's an interesting idea. Sadly, I think much of the lift being generated when the craft is stationary is coming from the very powerful propellers you're using and not the coanda effect. However, you are getting a very strong coanda effect when the hover craft moves forward. It doesn't really have any more practically than arbitrarily limiting a wing to flying only a few feet off the ground.

[@Poldovico]

I guess the question there is: did you build a Coanda effect hovercraft, or did you build a very low power helicopter.

[@fk319fk]

I am not sure it is the Coanda effect, it could be the propellers. My main thought about your instability is that it is similar to a fly wing.

[@pesqair]

he needs to make a box shaped one and test

[@dr_jaymz]

I think there is some effect, but mainly low pressure above the propellers. But then again, the propellers are using the coander effect too. The leafy wind tunnel showed there is little blowing downward and I think it was too optimistic for it to blow round 180 degrees! I think 35 degrees is pushing it.

[@triplem9805]

Would some cotton telltales around the hull (or a smoke generator) either prove or disprove it?

[@1Hippo]

Yes, i also think it is from the propellers. They are moving the air downward first, so there must be an equal force in the opposite direction (up). This will act on the propeller shaft and after all pulls the vehicle up. It does not really matter where the air goes after that, as long as it is not redirected up again so it would create a force directly pushing down, but i don't see any way how that shape would do that. A relatively simple test could be to change the propeller angle, so they push air just horizontal over the craft, which should also get redirected down, if the coanda effect works. You could even use the rear motors spinning in the opposite direction, then counter the backward force with a second propeller (pair).

[@hamjudo]

All it takes to measure the relative pressure generated underneath the hovercraft directly in terms of mm of water are a flexible tube, a bowl of water, a ruler marked in millimeters, and misc supplies to hold everything in position. Find a large flat surface and tape down one end of the flexible tube. Bring the other end over to the bowl of water. As the pressure should be the same at both ends of the tube, if you stick the tube into the water no bubbles should appear. Likewise, water should not climb the tube. Make an elaborate test stand to support the hovercraft at a suitable hover height over the surface, centered on the end of the tube. Alternatively, make 3 piles of foam core 10mm high and put the hovercraft on the 3 piles. Clamp, tape, or use a weight to prevent the hovercraft from leaving the test stand. Throttle up the hovercraft to a suitable test throttle value. This should produce a positive pressure underneath the hovercraft at one end of the air tube. Submerge the other end of the tube in the bowl of water. Raise and lower the end until the bubbles just barely stop. The depth of the tube at that point corresponds to the relative difference in pressure in terms of mm of water. Calculate the area underneath the hovercraft. Multiply area as measured in square millimeters by the depth where the bubbles stop and multiply that by the density of water in terms of grams per cubic millimeter which is 0.001 (1 milligram). That will give the lift due to the positive pressure, aka the hovercraft lift. Weigh the hovercraft. Measure the lift at various heights and throttle settings until you get bored.

[@GeraldOSteen]

I would love to see a collab with Mark Rober on some of these projects.

[@howardbaxter2514]

Imagine if Tom, Mark, and Stuff Made Here all collaborated on a project together.

[@bricology]

@@howardbaxter2514 -- you'd better invite Colin Furze too, or he'll build, and attack them with, a giant flamethrowing hover-saw.

[@TheHorseOutside]

Mark Rober donated to a eugenics group

[@thespud1094]

just don't invite Michael

[@KingOfTheKindle]

Add stuff made here to the list

[@benhill2561]

I love it when you science guys actually build things to help the rest of of see concepts in action. But I do have one question. Wouldn't the fans still produce some amount of lift even if they were mounted to a flat surface of similar size? I may not be visualizing all the forces correctly but it seams as if act of pull air downward and then redirecting it straight out horizontally would result in a net lift even without any Coanda effect.

[@fisch37]

The air will apply a force to the surface, so I think they'll cancel out. I'm not quite sure though

[@dakotaeaslick1733]

Lol yeah, I'm pretty sure his wing concept was not doing much if anything. It is just a helicopter that only produces enough thrust to lift 80% of the weight making friction negligible. I assume a flat sled would work just as well. Still super fun project, glad I watched.

[@TlalocTemporal]

​@@fisch37-- If there's a net downward motion of air, then there must be a net upward force to match. Definitely much worse than a normal helicopter, but sucking air downward is still something.

[@carneeki]

Nice slow mo, and the ad format worked really well. Great video Tom!

[@jimmyshrimbe9361]

Yes!! One of my favorite effects! Up there with Dunning-Kruger and laminar flow!! Thanks for sharing 🤘🤘🤘

[@hsmptg]

Do you think the lift is really caused by the Coanda Effect or is just the expected "convential lift" caused by two propellers on top of an object?

[@triplem9805]

Would a baffle above the main props reduce any direct lift, and prove whether or not the coanda effect is the main reason for lift?

[@forcemultiflier1746]

I was thinking of writing the same thing , yes -I think it's just a clumsy Helicopter !

[@badw01f23]

Not 100% sure but I don't think it would be conventional lift. The props are pushing air against its own body which is mostly flat on top. If it wasn't for the curved sides (causing this coander effect) then it wouldn't gain lift. Similar to how a helicopter with a large flat board attached to its legs won't take off.

[@mkj161996]

@@badw01f23 Considering how large and close to the edge the propellers are, I don't think it's possible to completely rule out the viscosity of the air causing some vertical lift. You can see in rotor airflow tests that there is a significant airflow change up to around 1/2 the length of the span past the propeller. A test with a rectangular hovercraft would be great to see.

[@hannorasmusholtiegel6044]

@@triplem9805 no ,the propelers would not suck enough air to the bottom and it would not work

[@Impossibly-Possible]

good idea but you need to put more smaller fans near the edge so the air does not have to travel as far to get underneath. at least what I would try.

[@lukashessling3125]

My friends jokingly make fun of me for watching educational videos in my free time (I promise for anyone who cares that I know the difference from jokingly and actually making fun of me) but some of these videos are super interesting, especially videos from this channel.

[@AlexJoneses]

"I'm surprised it's working so well on grass" *immidiately flips over*

[@Supreme_Lobster]

What fun is it if it can"t do a flip?

[@Nilguiri]

Your hat is on backwards! You must feel like such a fool!

[@bloodyxwolf2541]

@@Nilguiri chill, it was a joke

[@Nilguiri]

​@@bloodyxwolf2541 Jonesy Films put his hat on backwards for a joke? OK, if you say so, mate. haha.

[@woolfoma]

Well he did say he was surprised.

[@JakeBiddlecome]

The slow mo bit at the end - coolest thing I've seen on this channel.

[@MrRolnicek]

The coanda effect makes it more likely for the craft to tip over. Say you're sliding to the left. That means there's airflow from left to right (relative to the craft) Thus the coanda flow on the left side is going against the airflow caused by movement which means higher pressure and lower lift. At the same time the flow on the right side works *with* the ambient airflow which increases lift. That process is going to tip the craft over on its left side if my reasoning is correct.

[@jajwarehouse1]

Correct. This was the same problem that was run into with the VZ-9 Avrocar.

[@davidelzinga9757]

Seems like this may have also contributed to the nose dropping during forward movement. Incoming air may have slowed the movement of air going towards the nose of the craft. I wonder what the result would be of attempting a hybrid hovercraft, having a small hole under the lift fans, or moving the front lift fan closer to the nose

[@jajwarehouse1]

@@davidelzinga9757 Yes, that would be the problem with the nose dropping, also. Millions were spent trying little things like that because it always seemed they were so close and only needed one more little adjustment, but they could never get it to work well. Eventually, after making enough modifications, it would be either a helicopter, an airplane, or a conventional hovercraft.

[@nicopohl2060]

Excellent experiment treating the hovercraft surface as an airfoil, which incidentally suggests that the conventional hovercraft design has an inbuilt flaw, i.e. the fast airflow on the inside of the surface causes a lower pressure area and thus a downwards Coanda pull on the craft, which counteracts the pressured air lift effect. Food for thought.

[@bybecker]

People like you move the world. Beautiful work. Congratulations.

[@chethiyaakalanka2850]

Those slow motion bits were awsome ♥️♥️♥️♥️♥️

[@Henrik.Yngvesson]

The Helicopter effect takes over when it starts flipping.

[@GglSux]

As always a great and interesting video. I would have loved if You had attached some "streamers" on the hull and maybe an "fpv camera" inside the "cavity", All so that we might have gotten a better picture of the "airflow" over the surfaces... As always a fantastic watch, thanks a million for sharing Your passion. Best regards.

[@jonwebb9261]

Most convincing audible ad I've ever seen!

[@chucksannel7768]

You made a thing marketable as a toy that picks up leaves, you have earned my 6000000000% respect

[@mtbviper7153]

Tom, I challenge you to build a working rotodyne. Keep up the vids, love to see a new one uploaded every time.

[@matthewdunstone4431]

“These aren’t the droids we’re looking for. Move along.”

[@pilotofjet]

13:55 *deja vu starts playing*

[@rileyledyard4350]

I think the leafs colected show that a flat base would drastically improve your lift, I think there is some suction effect where the airflow rolls all the way into and up the bottom of the craft.

[@alaricsmith5558]

Great video. The velocity of the air hitting the leading edge increased the lift that edge, hence the flips and instability. Having adaptive electronics to balance this would make the whole craft far more stable. Perhaps, properly flanged, ducted fans would be a better option than propellers, as you will lose less flow sideways and give greater thrust control, with increased efficiency. Remember that most (almost all) hovercraft plenum chamber fans are ducted for that reason.

[@EnegeNG]

First of all, I just want u to know that I love ur channel and ur work! Please keep it up. But I gotta say that there's something off with this project, imo. I would have found it interesting to compare the lift generation of the curved body to that of a flat plate and then a brick sort of thing for example. Ofc keeping the same propeller system. You could then evaluate if it lifts because of the propellers working as propellers or there's something more. Because otherwise we only have a very weird helicopter... Then maybe try to answer why a correctly sized fan doesn't do the job when consuming the same power output. Maybe it's that the Coanda effect alone doesn't work, or the fan giving too much speed and not enough pressure to the fluid... I don't know, I don't remember much about these thrust generation devices at this point, but something like that.

[@DerSolinski]

Next time: Coander effect leaf collecting gardening robot...

[@123Hinne]

If you add two Servos to the thrust propellers, you could control the jumps or even fly with it as a vector-thrusted vehicle!

[@FeLix-fj1gu]

Nice

[@adobedoug2564]

That would add roll, you could have pitch just controlling the lift motors separately.

[@DarkVadekGaming]

So Tom, essentially what you made is a very inefficient vacuum cleaner that's shaped like the speeder that Luke Skywalker had on Tatooine??? That's actually pretty cool

[@FirstnameLastname77777]

This dude is soo underated

[@shotintel]

Love to see that run with smoke or vapor to show effect of air flow.

[@GravityGamesHD]

I first read “Canada effect” hahaha 😂

[@BeautyWillSaveUs00]

what will happen if i fill it with poutine and cover it in maple syrup?

[@Allan_aka_RocKITEman]

*_EH?!_* 😊😊😊

[@corison2058]

BeautyWillSaveUs00 dang it! You beat me to it

[@Artem4egg_]

@Flyingcrocodile46 ha... Wait... WHAT?!

[@marioradu3965]

Henri Coanda was a romanian inginer

[@TheDrdounut]

the slomo parts seems like a gymkhana parody.. kinda like it :D

[@mcdol13]

I really like how you do the time lapse during the "commercial" period of your video while you talk about Audible. I usually skip forward at this point in the videos but your time lapse kept me engaged! Well done!

[@glubux]

Luke : "Can I have my landspeeder back now ?"

[@minecrafter0505]

You should try cutting holes below the props to let some air into the body and make this a hybrid classic/coanda hovercraft. Maybe that increases stability / lift.

[@butchs.4239]

That, or try adding ballast around the bottom edge to counterbalance the weight of the motors and lower the CG.

[@CD-rt8wj]

ayyyy new Stanton!! I'm printing your flying wing next to me right now bruv

[@MrJob91]

@dante bromkovsky lol that will take agrs

[@ginosmovies]

An electric leaf vacuum cleaner for my lawn! Hey Tom, you are the next generation Dyson. Thank you for the great videos .

[@macnsteeze]

The slow mo is super satisfying to watch

[@elijahbrown3096]

I like the fact that he just had to make a line stretch and retract to animate the propeller

[@TheDoc73]

"Coander effect... coander effect... coander effect" Good thing you wrote it down, or no one would know what you're supposed to be saying.

[@sck5943]

it is coanda it is coming from HENRI COANDA the guy who invented the 1 plane

[@ursulmusic]

In its native language it would be written as "Coandă", and he actually pronounces it as it should. So the "er" in "Coander" would be the "ă", but without the "r". :)

[@cip1911]

@@sck5943 first jet engine flight, actually...✈️

[@FatmanZockt]

Hi, Tom, pretty cool project! I have a suggestion. Have you ever thought about smoothing out your 3D printing parts? I've already smoothed a few ABS parts myself with acetone vaporization and was surprised how well it works. The advantage of this would be that in projects like this, your surface would be smoother and there would be less turbulence and air friction. Especially with the Coanda effect this can be an advantage! I am looking at the blue motor-mounts or the drone motor mounts from the last project.

[@zuestoots5176]

Fun fact. acetone vaporization is a way to clear foggy plastic vehicle headlights.

[@rottelHQ]

Hi Tom. Me and Carla (8y) are enjoying your experiments. I think you should "preserve" the skirt an use the air between the (outher or inner)skirt and plastic for a more directed propulsion and avoid that way leaves. Anyway, we think there is more about the Coanda effect than meets the eye. A air curver surface before the propeler should help and probably save energy. Congrats and thank you.

[@bzakie2]

You’re actually demonstrating how planes fly. It’s mostly coanda and not the commonly accepted low pressure on the top surface of the wing.

[@boryswwa]

Isn't this a Coanda effect combined with the sideways air movement, when You're in "side drift" causing the "downwind" side to get more lift and therefore tipping the hovercraft over? After all, You are moving through air sideways inducing additional airflow over the hovercraft. Since the main motors give the hovercraft the amount of lift just below "lift off", the small amount of additional airflow could make one side to actually go past the "lift off" limit and hence the tipping over. That's just my theory.

[@willhaney96]

I dont believe the airflow is fast enough.

[@caeruleum780]

Me watching Tom play with a Hovercraft in his room with fast-spinning propellers with no safety walls or features on: *rapidly bites fingernails off*

[@StraightEdgeHippie]

"Hey, what if a hovercraft was designed like a helicopter, and instead of having seats for passengers, we put propellers."

[@datguymiller]

It's for cargo, obviously

[@growthisfreedomunitedearth7584]

in this design the passengers would be inside.

[@aaronfreeman5264]

A Surface Effect Vehicle could be modeled on our "Drones." I don't understand what you mean by replacing seats with propellers.

[@DannySullivanMusic]

that's right. 10000% perfect

[@Will_Forge]

I want to see you make another one, and attach it to this one with a central chamber, like this one and the other are nacelles to a larger vehicle. Then use a Gyro to reduce flipping. Sure it will just be a quad hover craft, but it might make it more stable. Or just put some springy rods that push off of the ground when it gets to an angle of about 30° or so tipped to any side. Just like 6 or 8 around the outside, maybe?

[@Will_Forge]

Also, is there a way to harness that pressure inside to channel it into forward thrust? Maybe that would increase air flow downward by creating a pull effect. Meaning, could you put a thin tube from the under chamber toward a rear fan that draws on that pressurized air for forward momentum? As it is, you're pulling air from above the vehicle for both forward momentum and upward thrust, which may be making a small vacuum above the vehicle. So there are upsides to both designs. Could you make it be both? As in, could you make 3 forward thrusters including the 2 you have plus 1 that draws air from the pressurized under chamber? Would that even help?

[@kxdsh]

The way it glides is really satisfying

[@techleontius9161]

_"In 2020 there will be hovercrafts..."_ 2020: *Hovercrafts*

[@fredlonbottom238]

Me watching Tom play with a Hovercraft in his room with fast-spinning propellers with no safety walls or features on: rapidly bites fingernails off

[@RaulTecar]

2020: Lovecraft

[@kaamilverma1602]

try attaching a CWW rotor on the right and left with a gyro so whenever it tries to topple they can spin up and get the hang of it ..... amazing content : )

[@guilhermecastro3671]

Also add some weight to the front so it doesn't lift like it was doing

[@DaveBlaser]

The look of it kinda reminded me of Luke's speeder in Star Wars.

[@JulesBrunoJjBaggy]

THAT JUMP OVER THE GRAVEL TRAP WAS SICK

[@ΓΙΩΡΓΟΣΒΑΣΙΟΣ-θ5τ]

The best coanda effect leaf collector I have ever seen!

[@FL0RI4NN]

Sooooo... if you mount the propeller low could you use it as a hovering lawnmower?

[@forcemultiflier1746]

I would love to see the model tried again with under side curve cut off !

[@adrianchupp]

I'm sorry Tom, I'm quite skeptical on this one. It appears to me that your hovercraft is being supported not by the Coanda effect but rather by the thrust produced by your rotors. Does it behave any differently if the top edges of the body are at 90 degree angles rather than the curve you formed in the foam?

[@TomStantonEngineering]

I'm not sure whether it'll still work with the 90degree angle as I haven't tested it, but I assume it wouldn't work. The width of the fuselage is twice the diameter of the propellers, therefore if the coanda effect wasn't working, the air would just flow outwards horizontally and not produce any lift (well a very small amount of lift due to the fast moving air being at a lower pressure).

[@McCardinal]

@@TomStantonEngineering but the propellor produces lift by moving air over its own surface also and not only by "Blowing air" downwards

[@TomStantonEngineering]

@@McCardinal Yes that's correct, the movement of air downwards through the propeller does produce lift. However it's vertical velocity is cancelled when it hits the top of the fuselage. Similar to being on a sail boat and blowing into the sail using an onboard fan, there is a net neutral force.

[@danmoonlight8965]

@@TomStantonEngineering Not so. Firstly the propeller generates lift because the blades are an aerofoil moving through air in the direction of rotation, as Henrik said. Secondly, your sailboat and fan analogy is oversimplified (and doesn't actually apply well to real sailboats either) - the net neutral force in the vertical direction is between the fan and the deck of the hovercraft, where that air is "pushed in, but stopped". Sideways air is pushed out all round, so net neutral force there. Above the fan, air pushed in... below the deck... nothing, so the overall net force is not neutral in the vertical direction. Rather than the sailboat and fan, consider a jetboat: It doesn't suck water from in front and push out the back - it sucks water from below the boat, and pushes out the back. So Adrian's experimental suggestion was valid - what does happen when you remove the curve from the deck, and eliminate the coanda effect?

[@stephenborntrager6542]

@@danmoonlight8965 I would love to see that. Nothing about fluid dynamics is intuitive, but I bet a square edged version of this would still work though.

[@jedexkid41]

this is kinda cool. the fact that you have more thrust than needed means that you can add weight, and you can add that weight underneath to help with the top heaviness

[@ThePatriotsFlag]

Fascinating from theory to proof, well done!

[@danielleohallisey4218]

You’ve invented a Coanda Effect leaf Roomba. Brilliant!

[@HadoukanFire]

How about adding colanders to it making it a Roomba coander colander

[@GuildOfCalamity]

The most overly engineered leaf blower in the world.

[@GENeric08]

Seems more like the power of the props then Coanda effect.

[@RedBlackDish]

I like how instead of moving the camera on your field test you made a wide shot, zoomed in on the footage and then moved the footage

[@llwdtp]

This was fun to watch. The Coanda effect vehicle does not have a natural height limit like the conventional vehicle has. That may be part of the instability problem. If there was a way to spoil the Coanda effect when it gets to far from the ground, that may make it more stable. Or you may add feedback to the vertical motor speed based on the height. The vehicle you built is not afraid of flying.

[@JustPlainRob]

When you have props on top instead of the impellers, is it really using the Coanda effect? It seems more like you've created a two-prop copter more than using the Coanda effect. It's not the air's adhesion to the smooth sides that's providing lift, but the initial pull upward from the props.

[@118Link]

congratulations, you've made a vacuum cleaner for your lawn. Edit: actually, I think it will fly if you put wings on it.

[@MohitSharma_calc]

I thought the same thing too

[@FG-vp6id]

honestly this flies better than the drone he made

[@Beevreeter]

Hovercraft principle: Force air down INSIDE the skirt Tom: Hold my beer

[@yiyuzhou3453]

I suggest you place the vertical propeller left and right. Then write a program tells the car when the car turns left, strengthens the left pressure to the ground; when it turns right, strengthen the right pressure. That way the car won't flip over during turning.

[@Astrawboy_NameAlreadyInUse]

What I'm telling here is 1, the thrust doesn't have to face every direction in 360 cone. It can be turned into laterally symmetric high-aspect ratio wing with 4 push-pull props, with propwash not interfering eachother in a way so that all wing surfaces are submerged in a propwash when they are counter acting the forward and backward thrust. So that if the lift is created upward, no side way motion is made. To counteract the propwash interactions between the individual prop units, put 3 or 5 wing fences in between. To stabilize the craft, it should have V shaped adjustable parachute, made of 2 sticks with a flat plate. So that the plates are constantly stalling having the arm. The drag would be increased in the tilted AoA, so that it would have a stabilizing effect. If the angle between the V lines is adjustable, it would make them efficient horizontal stabilizers. This kind of crafts operate at such AoAs so that it would be not feasible to use a normal airfoil for the dragchute. By giving the V-chute the ability to vertically align within the CoG, gives them the ability to land on them. Because these V chutes need to be at the most outboard of the craft, it means they have the ability to control yaw by adjusting the drag on one side. They have 4 legs to stand on by itself. Also it's the ideal launch angle for them to stabilize in this A position. Because the shape of the letter A is the embodiment of a portable ladder. To take the effect, use layered airfoils with 2 flaps for pull props, 2 leading edge movable slats resembling that of 2 the previous trailing edge flaps but in a mirrored fashion. So that they can not only redirect the flow, but they can work as ailerons. By the nature, it's better for the outboard wing to be in a puller configuration because they should fulfill the role of ailerons, even though the high chord ratio leading edge flaps kind of work like ailerons if operated with servo. It's entirely possible, maybe even smoother. But the point being it should be symmetrical laterally, I mean horizontally but with just 4 mirror angles. Not a circular wing because they are hard to implement with flaps, they are not particularly efficient at redirecting the flow as the increased surface on the lower side of the flow tend to get too thin to stick to. Also the part I'm referring now is producing the lift sideways, it's wasting a lot of the lift potentials on the sideways especially on your previous submission. The only use for this type of configuration would be to put the thrust in a sideway direction to begin with so that you get a faster horizontal speed unless you can simply just redirect the vector of the thrust by having a propeller shaft gear specifically designed for it. I know it's easier to simply rotate the motor itself at this point. The few parts interesting about the proposal I recommended in the comments above is that so the propeller pitch of the push-config propellers should be adjusted to so called "Negative pitch" so that they essentially produce either forward or backward thrust. The puller ones don't need this because only one "forward direction" is needed for all of this Vtol system to work. If you could produce 30% force of the horizontally produced thrust to a vertical vector as the separated values from the sum up of the force. You need like 3 times more power to create the same vertical thrust. Which isn't very efficient. Maybe it should have like very high rpm props with completely flat propellers for the much needed ability to produce thrust in both directions depending on the circumstances. If the craft is handled in a near 0 speed regime, the flite should be controllable with the thrust differences between the left rotors and the right rotors. It's just possible because of the props literally having no off-center forces working on them, no matter the thrust, the forces needed for the actuators to work on the pitch angle would be almost negligible. Because the CP is perfectly aligned with such a simple prop design. The V sticks changes the CoG dynamically, that means the pitch is maintained by either the flaps or the dragchute angle. The redirection of the flow would be better if the flaps are segmented fowler-type flaps with wide vertical gaps between them. But they would be hard to make the flaps as reversed leading edge slats aerodynamically feasible to push against the air, in a horizontal flight. Also the aileron's effectiveness at extremely slow flight would be reliant on propwash, meaning the power difference in each props would have like a noticeable effect on the aileron effectiveness. Also, the individual prop's thrust should be adjusted by propeller pitch angle but not with motor torque output, because it's generally not responsive, I know it can be responsive, but it's just that even under the same power output, even with the faster rotor speed, prop pitch would get enough thrust difference, maybe designing the props in a such a way so that they could intentionally tip to the stalling angle to rapidly lose power on flight, but that would disturb the propwash, messing up the said aileron effectiveness stuff. With that much thrust to weight ratio, there is not much reason to just release it face-to-face with the vertical direction in the launch. It would fly like a space shuttle, but for some reason, it might be more aerodynamical in a horizontal flight. I hope this let you find new ideas. I also want to see it flying.