Coanda Effect Hovercraft 

Efficiency is overrated

Next time we look at boob-tape

@@boden8138 my German heart can't allow this

JOEL You’re here too 😂❤️

Did you mean "Unconventional"?

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

lmao

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

@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

Sometimes science is testing a hypothesis

Absolutely correct!

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

Maybe covering the bottom will make it more efficient?

I need to see it

​@@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.

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

Definitely noticed the stripes though 😁🍻

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

Fit for the Queen's corgis!

He c&c s it.

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

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

flashback to honey i shrunk the kids RC lawnmower scene

Next Video: Lawnmowing Hovercraft.

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

have fun while you clean :D

No longer have to rake

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

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

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

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.

Hey I love your videos Atomic Shrimp

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

What a weird crossover indeed

i agree! precisely right!

rofl awesome comment

*outdoor roomba

@Wyatt Watling a roomba I'd buy

I was seeing landspeeders too!

Yeah, that was totally badass!

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

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

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

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

Mark Rober donated to a eugenics group

just don't invite Michael

Add stuff made here to the list

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

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.

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

@@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.

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

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

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

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

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...

@@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.

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

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

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

Definitely how to do ads without turning off your audience.

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

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

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

@@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.

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

Exactly! I was just about to comment the same thing

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

@@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.

@@strangelee4400 yeah, thought that too

@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). ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-N0IGrSjcBZs.html 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?

@@SeraphX2 Nice

Novur needs to make a square sided version to compare.

@@toxaq exactly what I thought, would be interesting

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.

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

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!

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

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.

​@@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.

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

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

@@Nilguiri chill, it was a joke

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

Well he did say he was surprised.

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.

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.

@@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.

@@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.

@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. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-uKXMTzMQWjo.html

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

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.

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

he needs to make a box shaped one and test

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.

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

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).

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.

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?

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

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.

@@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.

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

Nice

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

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

*_EH?!_* 😊😊😊

BeautyWillSaveUs00 dang it! You beat me to it

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

Henri Coanda was a romanian inginer

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

2020: Lovecraft

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

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

@@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.

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

@dante bromkovsky lol that will take agrs

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

It's for cargo, obviously

in this design the passengers would be inside.

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

that's right. 10000% perfect

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