Quadcopter Ground Effect Vehicle 

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The t Company Should sponser you instead of Sending Their lawers

5:02 Bigger under driven props are always quiet. We have 4 LiDAR quads and two of them are for city use, with huge props (35 center to tip) to reduce noise as much as possible so we don't get nutties aggravated when using them to map historic buildings.

You were sooo close to re-discovering hovercrafts with that large skirt :D

Loving these projects and where they do or dont lead.

Awesome build! "Generic storage container" got me off guard 😂 It's always fun to see people who hide behind lawyers get messed with. I love seeing your projects and am curious to see where they lead you to!

The bracing bars on the plate could have been used on the underside to act as a skirt to keep the plate higher and hence the “sticksion” from fast escaping air would be reduced

The t word company is probably fighting against becoming a generic trademark and losing rights to their cool word. In the end it's all very silly. Love the ground effect videos, keep them coming!

the reason why it "sticks" to the water when it contacts it is due to surface adhesion from the water, if you ever put a flat piece of board in the water and tried to lift it up you can feel it just stick like a weak glue

Wait, tupawupa box company actually sent you a cease and desist for showing their product under a positive light? Incredible

The effect you are describing at 9:03 is the air recirculating around getting pulled through the inwash while pushing down on the top of foam boards. It goes away once you are far enough from the ground allowing the air to go straight down breaking the circulation.

ain‘t no way you can receive a cease and desist from tupperware😂😂

The whole "ground effect" series is quite entertaining. I guess a cheap smoke machine would help quite a lot in understanding vortexes and potential behaviors before even going on water. I think you used something similar in a previous video.

I really appreciate your willingness to test designs even though they may not be efficient, its really cool to see them come to life!

For stability you need to put bracing type dividers between each prop zone

The reason for the "sealing" might be the transition between generating lift due to pressure difference and Impuls based trust. Propellers for aircraft are designed to accelerate big amounts of air with a low pressure differential. That's also why you don't get much better power efficiency at very low altitudes, you basicly stall out the props. You should try props with more but smaller diameter blades and less pitch.

With your skirt at low altitude air flowing under the props has to escape to the sides, thus creating a venturi effect between water and skirt, lowering pressure and ultimately attracting your craft towards the water. Same effect as when a ship moves close to a wall or to another ship, water in between has to escape quickly and sucks both ships towards each other. This increase in speed only happens significaantly when both objects are very close to each other, and is not significant when overing a bit higher / farther from the obstacle.

Cool. The best ground effect I've experienced was an MCPx hovering inverted an inch over a gym floor. It was actually hard to make it touch the floor. The tips would touch based on the angle but the center rotor button wouldn't!

The soft ceiling is probably due to a vortex from the thrust hitting the ground and circling back around to come back down on top of the blades, reducing efficiency until it powers through it.

Tupperware sent you a cease and desist letter???? Wtf

Bought a $250 quadcopter about 10 years ago. Small/medium sized. Had a thin plastic body, that when mounted helped trap thrust air. This has the benefit of giving it ground effect flight. Hovering roughly 1-3 inches depending on power setting. Would not fly if lifted up higher. Run it off a step, and it would drop down to GE height. It gave me about 50% more flights time. I could run up and down the street/sidewalks. Clearing fresh cut grass off my drive and sidewalk. Whole time using hardly any throttle. Then had to give a decent boost of power to lift it past this GE height. Sorry, just always thought it was a neat little thing. And then stumble on this video.

What if you put your foam support pieces on the underside? Could you make air directing channels to increase stability? Anything to make it more stable than an air hockey puck. Also, it is amazingly cool to see experimental aircraft concepts play out in real life. Please keep it up.

It’s sad that the company doesn’t allow you to use the t word and instead sending a cease and desist letter

I’m most impressed by how quiet those big props were! I think you should do a project to make the quietest quad copter you can. Mark Rober had a video recently with a really strange prop design that was supposedly really quiet.

That's actually the best concept quadcopter in a flat platform. The blades give you flight if needed at altitudes above waves, but hover in ground effect is very efficient othertimes, speed not so important, think about what I just wrote if you want it as a four seater to go on a trip somewhere, its a very capable concept with a combustion engine. No pilot licence or airworthiness needed.

oh hey, I used to play with that effect when I was younger ! I had on of these tiny toy quad without any automatic stabilisation that I just could not fly without crashing it everywhere, but I noticed that if I gave it just enough throttle to get off the ground (flat tiling in this case), it would hover at about 1-2 cm from the floor, self-stabilize when tilted and never really get any higher. so in the end I had a lot of fun racing my little remote controlled air-hockey puck around ^^

Hey, I have had success using resonance analysis tools in Solidworks to identify issues like you used the high speed camera to identify. You can compare the results of a simulation to a black box log to verify. Mechanically solving these problems iteratively in CAD is very satisfying! Love your videos sir.

My 8th grade science teacher had a "hovercraft" which was an upside-down table with a hoover vacuum, some kind of tarp that would fill with air and blow it out the bottom, a chair screwed to it to sit on, and a Hoover vacuum powering it. It was so frictionless that with extension cords we were able to coast down the whole hallway with one push.

You probably though of this, but putting a reversible ESC on your forward prop would probably allow you to stop easier. Great video!

the chord of the wing for a prop is not the diameter of the swept area, it is the width of the propeller itself, which is trivially small

love watching your videos as you explain all these terms in a way that's really easy to understand, while also making the video entertaining!!! I don't think i've ever clicked off one of your videos. Keep up the good work my guy.

This makes things tingle. Building something that worked closer to a jet moto style hover craft is a dream.

We want a clip about a flying flame thrower for weeds that can be used with a lawn mower against zombies

There was a uk microlight aircraft built in the 80s called the Chevron. It was designed to takeoff into ground effect, accelerate, then climb.

Interesting... Maybe you may want to design something that moves weight forward when the front goes up, and same for the sizes? My brother worked on something like that in the mid 90s for the French carrier, that's how they can land planes flat in the middle of a storm: move weights.

Need bracing between the boom arms and using a controller with betaflight and adding some RPM filters would go a long way for stability. The suction to the water was surface tension, you can stop that by adding tiny little "ice skates" to the underside so that they prevent the entire surface from touching the water at once

Instead of flipping those motors and props upside down to get them closer to the water, leave them upright and surround each prop with a foam duct. With the duct, it’s no longer essential to have the motors so close to the water because this will drastically increase the pressure below the prop and create a more compressed air cushion below the craft. I’ve built a number of foam hovercraft many years ago using this principle and it works.

Awesome video! Regarding displaying power instead of current: You could use mavexplorer (part of mavproxy) and use that to plot current*voltage, as you can easily define your own graphs there. If you do a lot of Ardupilot log analysis it's worth checking out

RE the floats under the props. It looks like as the props spin up, the rotation of the floats cause the water in contact with the floats to flow outwards from the float center (centripetal force). This cause the water to evacuate under the floats. You might experiment with texturing the bottom of the floats (hot iron), such that the rotation draws in water (iow make a spiral texture).

The weird middle altitude zone is probably from the top of the convex/vortexs like on a wing tip washing back down on top of it pushing it back down✓ Thanks for posting!

improving the design of the skirt with holes would end up reinventing the hover craft, with its flexible skirt which makes the altitude of the ground effect higher and provide a margin of error when the waves comes closer or when the hovercraft loses altitude a bit. The hovercraft skirt makes it more efficient as well

That sound profile from the huge props would be a super cool rabbit hole to go down. Would be fun to explore just how slow a prop could be turned on a quad without completely losing control authority.

TL:DR "Skirtless" HC's (GEHC's) do actually have skirts... kinda So, I rabbit-holed on this. The long and short of it is: you DO need a downward facing sidewall all around the underside of your deck in order to disrupt the airflow and develop a pressure cushion You ever see that experiment where you hang 2 ping-pong balls then blow between them and they get pulled together? (related to the Coandă effect) That's what was happening here and "sucking" your craft to the ground/water. Fast airflow beneath the craft creating a *low* pressure stream was defeating your lift, pulling the craft down. You need to contain that airflow in order to develop a *high* pressure beneath the craft. As it turns out, if you'd added a sidewall of just a Cm or 2 around the perimeter of the underside of the deck, it should do the trick. This is analogous to the vertical sidewalls needed on your airfoil type GEV's in some ways; containing the air beneath the craft where it can lift the vehicle rather than being knocked away without the desired lift addition.

The reason the foam skirt would get "suction cupped" to the water is bc of the surface tension of the water and the microscopic dimples in the foam board. 👍👍

This is essentially how i teach people to manually fly quads, I get them to lift the throttle so it turns into a hovercraft and learn to control it on the floor before they add Z axis.

Love the use of the Pentax 50mm on modern hardware!

As I understand it, decreasing voltage means higher amperage for same power, thereby more heat for same power. If anything is seems more logical to increase voltage, to reduce heat generated for any given power output. Within the voltage range the motors and controller can handle well. Reducing voltage limits the possible power output, and thereby possible heat generation at full throttle, but it still produce more heat for a given power output. So can we hope for experiments trying to achieve low noise levels, using things like large props?

I love your videos and generally scoff at peanut gallery comments about minor errors but if anyone wants to know… Those birds are not puffins they are coots (Fulica americana) I just live right over in Ellensburg. It’s really fun to watch your footage of Seattle.

9:30 -- The animals we create are morally equivalent to our own children. They are owed the unconditional love and protection of their creators. The experiences of animals are real and matter. Their suffering is identical in nature to your own. It harms us when we take pleasure in cruelty and violence.

so funny when a company sends you a cease and desist instead of taking advantage of the free marketing.

You should spray some of that hydrophopic coating on the underside of the foam panel. That will pretty much completely prevent the craft from being pulled down by surface adhesion if it happens to touch the water.

you could orient the motor/prop to stabilize the banking at high speed, front motor should be tilted to blow a bit towards the front, so when the quad tilts up, the front motor will be less horizontal and loose vertical lift, stabilizing. Same but opposite for the back motor. The other effect is that at high speed, less air will enter the front props, because the top face which is vacuuming is oriented towards the back, making the lift less

You can play around air flow path - if you add some channeling foam pieces, position of each propeler would be either raised, or air could be distributed through saw tooth like edge skirt around. Now when one side goes up, air from rear motors will go towards less resistance path - and destabilise craft more. Without channeling/enclosure for prop wings you have a lot of pressure losess especially in radial direction, which maybe contributes to vibrations - each propeler hits wake from its neigbours. For mixed case when both pressure and volume is needed just lookup for industrial fans enclosures - they arent straight, but slightly narrowing/ rarely expanding. It allows for some design tweaking, where we would like to find sweetspot for motor efficiency and flow requrements. wrapping central unit in some foil, would reduce air resistance at fan "inlet", its not that obivous in steady flight, but in hoovering mode You calibrated stabiliser, and in horisontal flight, its adds uneven air wake for front/end fans.

3:51 someone literally gave you massive props ;)

The suction effect might be helped by rounding/shaping the bottom edge of the skirt such that that the air pressure is guided out under the skirt.

I got to ride aboard the SR-N4 hovercraft from Ramsgate to Calais in 1969. Well, actually I was the annoying youngest child and lobbied loudly for us to use the hovercraft instead of the conventional ferry, and my parents humored me. It's telling that regular ferries are still used even decades after the opening of the Chunnel, yet the hovercraft are no more.

BTW, Hovercraft was a registered trademark by Saunders-Roe aircraft company (later Westland) so other manufacturers of commercial vehicle couldn’t be called it hovercraft, they need to be called Air Cushioned Vehicle. Speaking of Saunders-Roe, they built the first jet powered Seaplane, Saunders-Roe SR.A/1, pretty cool project.

The large props on mismatched motors were probably less efficient due to I^2*R losses not magnetic saturation. Saturation means the torque stops increasing when current is increased above saturation current. This means the flight controller would not be able to maintain control no matter how the PIDs are tuned because the motor would not be able to achieve the requested rpm. When the quad responds to a pitch disturbance the motors on one side can slow down but the motors on the other side wouldn't be able to speed up and even if it could stay level it would lose altitude. A higher Kv motor has lower Kt regardless of motor size. Kt=1/Kv in Si units no matter the motor size. Bigger motors are thought of as higher torque because they can handle higher current without burning the winding or saturating the stator. A huge motor and a tiny motor make the same torque with the same current if they are the same Kv, the big motor needs (and can handle) more current to make more torque. Big motors also have smaller winding resistance so they will draw more current at the same voltage. That means having high Kv motors on large props will use more current than properly matched Kv motors on the same props. And it's important to have fairly close matched motors and props because motor heating goes by the square of the current (I^2*R), so having 2x too high Kv means 2x higher winding current and 4x more motor heating and inefficiency. Running the high Kv motor on lower battery voltage does not fix the problem that the big props need more torque (and current) to spin. The reason quads use higher voltage than the motor requires for the target prop rpm is because peak current is determined by winding resistance so running more voltage will allow higher current spikes and more responsiveness to disturbances like gusts. Basically it means you can achieve a better PID tuning. The esc pwm duty cycle and motor inductance act as a buck converter. If a 100kv motor needs 10v to spin 1000rpm, and the battery is 20v, that means the pwm will be 50% duty cycle. That also means the motor current will be 2x battery current since power is conserved. For example, if the motor needed 2 amps to spin the prop 1000rpm, the battery current would be 1amp in this example. So running extra battery voltage also lowers battery current (but does not change motor current). Since this buck converter effect is not actually 100% efficient, and higher step down buck converters are less efficient, this is why you don't just run as high a battery voltage as you want. It took me years to fully understand everything I just said because some of it goes against intuition we have as RC hobbyists. We all know if 2 different size motors have the same Kv the bigger one will make more torque, but that's because it's drawing more current, if Kv is the same Kt is the same too. We've also all put a higher Kv motor in our model and got higher speed and torque, although I just said a higher Kv motor has lower Kt. The reason for that is the higher Kv motor has so much lower winding resistance it can draw enough current to overcome the lower Kt.

That freefly amplify feature is pretty amazing. I know that special software exist to process and see vibration from video. Didn’t know that freefly had that feature.

About 1 to 2 decades ago was the Moller Flying car. They had a flying saucer configuration with a centrally mounted pilot. Eight horizontally mounted fans provided ground effect lit for this experimental air craft. Subsequent models never achieved much more than a hundred feet off the ground. Perhaps a bit more than that.

The AVROcar VZ-9AV and the AVRO Project 1794 aka "SILVER BUG" and "project Y-2", had similar ground effect stability problems.

Love to see the transition from ground effect quadcopter to an overpowered lift hovercraft

Can't wait for the eventual Quad-rotor FPV Solid Wood RC Ground Effect Toroidal RAM-effect Foam-Wing Lawn Mower on a Car Boat Snowcat (with lasers).

Pushing the air under the shield towards the water increases dynamic pressure (and reduces static) so getting suctioned down is pretty logical. Depending on distance and air volume of cause.

Basically you reinvented the first hover craft. Love the projects :)

This was a really cool video with lots of different physical effects in evidence - ground effect, vortex ring state, surface tension, EM force, and quite a few others besides 😀

Yesterday, I say my friend's new Mavic mini 3 pro for the first time. It was tiny and so quiet. A real masterpiece of engineering and a work of art.

The suction to the water you saw at 9:00 is probably the venturi effect. The fast flowing air between the water and foam makes a low pressure high, velocity area! Therefore sucking the foam (and quadcopter) down

I like these videos because they show *why* the peope who came before us gave up on these designs and went the route of the hovercraft: it's *much* more efficient and controllable. A hovercraft can take a hit from awave or a sandbank and jsut keep going. THe skirt makes sure of that. A low-flying plane will simply crash and kill it's occupants. It's klike watching somebody experiment with alternatives to cars and allways end up with a train.

Tupperware PR here. Please don't freely advertise the resilience, quality, and air/water tight seal that our product affords our customers.

Ground-effect quadcopter has been done. Check the AeroVelo Atlas. It even carried a human.

Your ground effect vehicle got this song stuck in my head. “Ain't nobody gonna break my stride, ain't nobody gonna hold me down, oh no, I got to keep on moving” 😂😂

Maximum ground effect is accomplished when hovering over smooth paved surfaces. While hovering over tall grass, rough terrain, revetments, or water, ground effect may be seriously reduced. This phenomena is due to the partial breakdown and cancellation of ground effect and the return of large vortex patterns with increased downwash angles.

I like that you don't bother pretending to keep your microwave clean for the ad

You've essentially just recreated a Hovercraft. The UK took the design of such to the absolute extreme, but they simply couldn't compete with other methods of transport.

The plates kill me every time 😂. They are the same ones my parents had when I was growing up and I've never seen them anywhere else. And my word, how petty of Tupper...those one people. Cool video like normal 👍.

You need to synchronize the blade weight (propeller position) to be exact mirrors (diagonally) to minimize the vibration, or use different propeller style that is always balanced.

As soon as I heard the word "jiggle" I knew a song was coming, but I figured it would be another remake banger.

8:50 Hey, it's a flying fold-up picnic table!! lol

Should have used the smaller props. 1. Because of the vibration problem. 2. Because the effect that makes horizontal props less efficient than wing for the ground effect is smaller. Basically, wings achieve high level of ground effect by moving along the ground and compressing the air in between. Now, when you replace the wing with a prop, half the prop is moving away from the direction of movement, which, to oversimplify, means that only HALF of each prop is generating a useful ground effect while moving, because the blades moving "backwards" does not actually compress the air anywhere nearly as much. So, a ground effect quadcopter is basically just a way to make a really complicated and ineffective hovercraft. It's a fun idea, but, probably never going to work well.

The “soft ceiling” you mentioned the skirtless version has is exactly what you’d expect for a working ground effect.

13:10 Had seen this process used for analyzing machines vibrations, very useful! Nice to see it available

8:53 The suctioning is called the bernoulli effect that's a different Problem... It's what normally makes your wings lift :)

Your power losses are more likely due to both pulling spoiled air into the props from putting them under the arm, and resistance losses due to the low battery voltage compared to the overall circuit resistance. Your PIDs are also likely correcting too fast for the slower blade precession and related torques and vibrations, causing heat losses in the motor windings from superfluous switching, and switch rates too slow to gain efficiency from a tuned LC resonance (like how sunspot CMEs overheat power line transformers). This may also be one of the contraptions where an air duct could be beneficial around your props, and with a large bellmouth output to create a high pressure zone when it approaches the ground/water.

When the Jiggle rap dropped, this old man was laughing with gusto. Thanks for that!

Hovering is the most inefficient phase of a helicopter's flight. They actually create a moving column of air, and have to fight to stay aloft in it. They're more efficient when flying into clean air, so that'd be another phase to compare efficiencies with. While in hover, that moving column of air has to go somewhere, usually everywhere, and the aircraft gets very twitchy, making low altitude hovering computationally difficult. Looking forward to more videos of your experimenting and learning.

13:11 This tech needs to be 'tested' at the beach, gym or even a dance studio for human kinematics studies. 😎

He's 1 step away from discovering the flexible skirt hovercraft!

12:39 from these shots it does look otherworldly, like a hoverboard or Luke's landspeeder

I'm so glad those propellers got some use!

8:51 surface tension. I feel so smart now that I knew something this guy who builds freaking drones didn't :D

The ground effect is really noticeable when hovering an RC helicopter upside down. That why you see pictures of models hovering with the blades skimming the grass. It looks really hard, but it's easier than a normal hover because the model is just bouncing on the ground effect, and you can really reduce the throttle. With something small like the Blade MCPx in a gym with a smooth floor, the rotor tips often scrape the floor.

I do anything to be Daniel's wingman. Give my life some meaning doing things I love. Daniel how can I help you!!!? I'd pay you to work for you. lol. Please keep it going. So glad you still can produce new things after so many years.

Some very simple front end aero would help immensely, it would only effect movement at higher speed and only take effect at a specific "fail safe" type angle

I aint sure if it my lazyness or poverty that keeps me from doing stuff like this but either way I am glad some folks are posting themselves doing it.

I love these "I wanted to see what would happen when I..." engineering videos haha this is great

I'm just pleasantly surprised you basically made a really big tiny whoop

13:20 The "jiggling" reminds me of the motion arrows make after they are shot from a bow.

You need to make a course on how you do the basics of these things, such as tuning the remote, servos etc

I don't know if you considered this, but since the ground effect is stronger with a low aspect ratio wing you might get a better effect using a low profile propeller more similar to a fan blade. You would have to custom make them though since I doubt anyone makes them.