Impressed by your prescience of following your quest. Watched all the levitator Videos . Gives me inspiration to continue my own projects. Thanks for sharing the honest path of innovation.
Regret to disagree with some comments below as lowering the CofG leads to INstability - Flap back and the pendulum etc. ! The blade pitch angles look to be less than rigid as the blade that ended up pointing to the sky went into negative pitch causing the disaster. We should perhaps make sure the c of G of the blade is coincident of the centre of lift to promote pitch stability. So sad to see this early trial end up this way after the majestic serenity of the earlier machines. I suggest further early tests be made with the base fixed to the ground where early rotor instability might be less damaging. Wonderful project, well done !
1. The main mast is not rigid enough: It visibly bends under the loads. 2. There seems to be some degree of coupling between the rotors, leading to vibration, likely exacerbated by: a) the high angle of attack (most of the lift is due to air being pushed downwards, not by a low pressure zone on top of the wing), and b) the rigid bracing. IMHO, nothing that disqualifies the concept. Just a little tweaking needed. And great project by the way!!
Great effort!! Some observations: 1) Central support mass needs to be stronger -2) Lower center of mass needed (add weight at base) to add stability?? and -3) Turbulence from the wings/flaps are creating instability between upper and lower rotor assembly. Good luck!!
i may be wrong but i feel like the main advantage of a coaxial rotor setup is the torque cancellation effect. but in your case since you are driving them with the tip motors you dont have any torque to cancel so you are left fighting the disadvantages of the coaxial setup, ie vibration from the lower blade interacting with the wake from the upper blade and double the part count. i think you were on to something good with your earlier single rotor design and i bet with incremental improvements you could make that one fly really well. i wish you the best of luck whatever you decide to do!
was the control simply out of phase?... one side lowered, and then the blades seemed to go negative pitch even more dramatically the further it leaned before the blade flex/collision. These are such groovy machines, I look forward to the improvements!
Wonderful! Thank you so much for sharing your experiments, it is very generous especially to share your disappointments. I hope you don;t mind me venting some ideas.Imaging two control surfaces in front of each propeller, vertical and horizontal able to define the circle and combat wobble. Each propeller unit has its own sensors and could be thought of as one of 6 planes flying in formation. The pitch of the main propellers could be controlled by a separate system. The canards of each power unit would have the leverage to have more control. I think they could control wobble in every direction. Thanks again for this great channel!
I'm sad that your recent attempts have had disappointing results. Since tip propellers don't generate reaction torque, there seems to be no advantage to using counter-rotating propellers. But new attempts are worth trying because you never know until you try. Your bold attempts excite me!
Agree that it seems to be the spine flexing that's the root of all your major woes, it's got a lot of asymmetrical forces on it and can't keep the rotors parallel as well as it should. You can hear the thrust props collide before the crash itself occurs because the spine flexed and the clearance was closed. Still a promising design though, much more scope to scale than the first levitator imo! Think of the wingspan a single rotor design would need compared to this design. The original levitator seems so good because it had a lot more development...
I see courage in your willingness to experiment, in your objective assessment of the outcome, and your decision to move away from unsuccessful approaches rather than being invested in them. I look forward to seeing your next steps.
Balancing such a large mechanism without NASA level engineering is a challenge, so some structural compensation would seem to be required to handle negative vibrations. 🤷♂️
Balancing should be as simple as attaching half of the machine to a bearing on a wall like a wheel or simply putting on its side on a stand that is attached to the axel, the heavy part will spin to the bottom and weight needs to be applied to the opposite side then it's rotated let settle and repeated. You can achieve quite good balance this way the limiting factor however is the drag or friction of the bearing this affects the "resolution"
I don’t get why you put all the heavy stuff like batteries and controllers into rotation when you’re having slip rings anyways? Must be a nightmare to balance that and even then, any change of load on the wings would bring this out of control? Wouldn’t it be best to place all the heavy stuff on the axle to have also a stabilizing momentum there? Anyways, nice project again. I am watching!
Great to see you posting again. A thought,,,, could you run a thin steel cable from wing tip to tip, creating a tensioned triangle to help stiffen the structure and maybe a way to balance the prop. I've had a vaguely similar design in my head for a while only using hub motors on a single shaft.
At the beginning of, during spin up, there’s a neat optical illusion going on. I couldn’t tell what directions the blades were rotating…sometimes they looked like they both were rotating in the same direction.
Love your innovation and diligence! Future testing might involve a central axle, which slips into a tube, mounted in the ground. A bungee of sorts would prevent axle form escaping the tube. This would allow for lift and balancing without resulting damage to structural framework. "Nightflyyer" (on TH-cam) made a support, like this, to pre-flight test his RC helicopters. I followed his method, and made a couple of my own to test the RC systems... Tx and Rx, prior to free-flying, learning that some folks have released models to the air, only to have them fly off... never to return.
Ok. As a model builder. First build small. Make changes on a small model. Redesign as problems occur. Make it as light as possible. Test. Get it to fly. Test. Train yourself to fly that model. Prove it works. Build bigger. Test. Prove it works. Build bigger. If you can make the small one fly you can make the full size one fly. It saves a lot of time and money to start small.
I think that that is an excellent suggestion. The ‘wobble’ at startup, perhaps instability is a better word, should have been easier to catch and correct with a smaller (much) model, as opposed to the crumpled heap on screen. Excellent idea.
Every failure is progress :) I think that with a rotor powered like this that there is minimal torque on the main body of the aircraft. Therefore I would pursue a single rotor design from now on. I would also have the batteries and electronics located in a fuselage below the main rotor to give more pendulum stability. But hey I am just sitting here typing ideas and not actually doing the real thing like you are. Respect to you :)
Take it from Bob Ross there are no mistakes only happy accidents, what a great opportunity for groth and new creative ideas that stem from this little accident next versions are going to be even better
I can feel this is leading to further adventures in aeronautics. It's too easy to let things bring you down, but when you can analyse your footage and work through the physical courses it can lead you to future breakthroughs and better futures. I wait with anticipation.
At 8:24, the skid touches the ground. This sets off a chain reaction of events leading to the rotors colliding. This is an issue with full size copters as well -- bad things can happen when the pilot doesn't get it clear of the ground and the skids touch the ground. It sends a vibration that escalates and completely messes up the rotation of the main rotor.
Always tough when a design have high hopes for doesn't work out. But, you have the attitude! My immediate thought was that the rotors found the resonant frequency of the main structure and shook it so hard it that the central column bent.
Maybe you can build some kind of testing contraption, where it can only move up & down while being supported! Like on a vertical wire or metal rod/pipe **insert metal pipe sound** going through the middle 💚💚
I love your work, thank you! If you made the lower part, the bottom of the stand heavier than the top part then it will stabilize much easier while creating a safer landing. So you could for example place the batteries at the bottom point of the design. Hope to see more of this and that there are some kind souls out there that can help with a little financial support. 👍 Maybe if you skip the main battery pack, just use enough batteries to maintain a stable flight and make the wings covered in solar cells. 😅
Looks like it bounced on the ground on the side near to us and that caused the upper blades to collide with the lower ones since the central pillar essentially bent (probably a lot more force on it with the propellers moving than stationary). Check elastic limits/flexibility under 1/2 the weight of the whole system and with a lever effect of the base support at the bottom of the lower prop connection. I think using 2 or 4 blades would provide more stability in the interaction when the blades cross each other, since the opposite side relies only on the interaction of a single prop and not two which could amplify problems...
Really disappointed for you, all that work with little reward but it did look pretty cool while it was spinning. plenty of salvageable parts for the next version. Coaxial's hey, over complicated and troublesome. I wonder if the central tube was the first thing to bend causing the crash. As we know without hinges on the rotor gyroscopic forces are transferred from one rotor to another through the connecting tube.
Every time a paddle from the lower rotor comes around the front, the back of the base lifts off the ground. Def a balance issue. Can not wait to see it in the air tho. Its beautiful! Looks like something straight from Ds Vinci's workshop!
Rule # 1. As I was learning to fly RC copters, to prevent tip overs I attached X shaped sticks to the skids with wiffle balls on the ends to keep it from tipping over if the trim was off. That way I could start a liftoff without fear of tipping. Adjust trim and try again. CHAIN IT DOWN so it can only rise a FOOT. Adjust and try again. If it tries to SCOOT in ANY direction during liftoff, start over. Tweak and try THEN set her free.
Too bad. Looking forward to your next crazy idea. ...on that note - Using three of the single rotors arranged in a triangle (like a quad drone, but tri) with a seat in the middle might be interesting. A bit like to one you did with the dozens of drone motors and props. I would be fairly stable I'd imagine.
one of the control links broke.. the angle of attack goes to negative pitch. right before blade hits the ground. You can not see the mechanical failure, but you can hear it happen right before the blade goes negative pitch
Wonderful... maybe only one rotor should have active gyroscopic stabilisation? You might be getting destructive coupling between two active control systems.
That is pretty rough, I wonder if you had some sort of structure to hold it in place. Maybe a large metal pole to support it from might help in case it develops an unstable oscillation, or if there is some sort of roll torque due to the propellers spinning?
I may be wrong, but I believe that there will always be forces in the design that take the axis away from the vertical position. And there are devices that easily solve such problems. These are gyroscopes. Probably you will need two gyroscopes - in the upper and lower parts of the axis. Возможно , я не прав, но я считаю, что в конструкции всегда будут силы, уводящие ось из вертикального положения. И есть приборы, которые легко решают такие проблемы. Это гироскопы. Наверное нужно будет два гироскопа - в верхней и нижней частях оси.
It's hard but ideas help with our need to express ourselves. A gyroscope will help stabilize the craft. It's not about weight but rotational inertia that makes the gyro effective. Like a bikes wheels. Hopefully this will help. Cheers and keep up with your efforts.
I think you broke a pitch link causing that cracking noise on the lower blade that is at the back at the time. You can see it invert as it comes around and drives the craft over. I feel for you after an obviously laborious build. Thank you for sharing this journey.
Very cool project. I don't know enough to give any constructive feedback other than setting up more cameras at different angles would give you a lot more to review and learn from. Keep after it and thanks for sharing!
Hi there. I know its been a couple months, but I also watched Your video over and over ... and over again. If You are still trying to figure out why it went wrong, I think I actually see exactly what happens the first second after the cracking sound. Also I dont think stuff breaks at 8:19 like someone suggested. Anyway.. Set Your TH-cam speed to 0.25 to verify or disagree with my findings. Navigate to 8:20 and start video, breaking sound at 8:21. Now pay attention to the lower prop blade that is just about to go behind main shaft. When it appears again the pitch on this one blade will go from positive to really negative in halv a rotation. This results in this blade's lower support rod being bendt heavily as seen 8:24-8:27. I think the reason for the breaking sound was Your mechanism to rotate(pitch) this spesific wing breaking. I got some experience from building/repairing rc helicopters for customers earlier, and things not perfectly straight will always vibrate a lot on the ground. Usually a lot of the vibrations and shaking on the ground will go away once properly in the air It's such a shame we could not see this fly properly before the crash. 😢
It seems to be caused by the cushioning between the two nodes. It seems to be unable to withstand the lateral load and a sprain occurs. My suggestion is to increase the diameter of the middle node and use bearings between the two bodies. If there is a spine that extends along the entire vertical line, pass it through the middle of the entire structure. A very successful product. Congratulations.
Just analyze the weaknesses and the strengths. Learn from it all. There’s a treasure trove of information in that hop and the crash. I think the pop was either a prop strike or one of the blade tubes kinked at the root. Just guessing. You’re right about the blade tube weakness. It’s the root that takes the brunt of the load. Make the disks larger diameter to support them better. Also the larger disks will provide gyroscopic stability (like flywheels). You’re doing something amazing. Keep it up. The goal is definitely reachable!
Whilst the Levitator 3 cannot fly fast horizontally it can fly a parabolic path. ie. Climb upwards whilst pitched forward. Still a big success in my view.
Opinion... it appears a loss of stability caused a loss of lift and hence contact of the blade systems, after touching back down... so perhaps the central shaft needs to be a three legged design (like a radio tower) with hubs for the prop mechanism to rotate on, creating more initial stability during power up... and maybe some load added to the landing leg. 🤷♂️ My layman’s observation. 👣🕊👽
😮😮What I don't understand is why it doesn't have a landing gear that's infinitely more stable, with more projected surface, so that when it destabilizes, it doesn't lose balance and remains stable on the ground. Right at the beginning of the video, it was clear what the fate of this beautiful aircraft would be.
The crash makes it look like it was blown over. I did not hear the crack, but that must be at the heart of it. 🤔 I suggest as long as that central mast is wavering you will not fly successfully. Good luck!
Ваш эксперимент был интересен,спасибо! этот момент действительно -путь к дальнейшему.Как мне кажется,во вращении ротора не хватало стабилизирующего гироскопического усилия.В радио управляемых моделях соосной схемы устанавливают гироскопы,у вас тоже соосник...
Looking at it frame by frame it appeared to me that after it started to list the main tube (vertical) looked like it bent between the upper and lower and allowed the upper rotor blade hit the lower blade.
Due to the buffeting inherent with counter rotating props they need to be either extremely narrow like helicopter blades or short and rigid. Also, move as much mass as possible to the bottom of the rig and decouple it from rotation so your fighting as little inertia as possible. Just suggestions, hope it helps!
I thought of this a long time ago for the human powered design! Your drive propellers should be Position in the spar support location witch will give higher rotational speed. But you need to consider better weight and balance to keep vibrations down.
Seems premature to give up this guickly.its facinating to watch.also did you think of shortening the cables on the single rotor the install a low tension sppring in the cable ends, to effect a small amount of flapping effect?
Kinda hard to keep track but I'll say you got a sync issue on top of a slightly off vertical shaft, before the crash. It would help to distinguish the blades. Color coded, different patterns, numbered or whatever. You need to easily tell when top and bottom are out of phase. Looked like the two blades I was tracking met about 30° early then it started tipping. Starting to wonder if a faster µcontroller would be a quick fix, after the rebuild.
So, just a couple of suggestions. Looks like you need a ballast weight in the bottom to help stabilize the craft. All of the weight is up high, and it's top heavy. Also, it appears that the rotors spin independently. Have you considered locking the rotors by adding a planetary gear in between? I feel like it might help with rotor synchronization if you did so. You should still be able to affect lateral rotation by powering up one rotor vs. The other, but it would lock blade timing. I think these two changes would yield some better results without changing the entire design.
Would slower wing would improve such violent shaking, these ‘flat sails’ didn’t provide so much lift. P.s. I kept thinking this was black and white, then I saw the grass was a green shade of grey. Maybe a bit more saturation?
Outch. Sorry to see that. Any particular reason for contra rotating rotors? You are producing torque on the rotor tips so minimal torque effect feeding back into the system.
The main structure is bending a lot. I’m thinking it is because when the wings move relative to each other the two different wing structures cause different lift vectors depending on how they are rotating relative to each other. If the main structure that the wings spin around is more rigid that would be prevented. A bit of a guess granted. But it shouldn’t be bending like that
😭
Thanks for sharing. The best of luck with your future developements. Even the failures are worth the watch.
well well welly welly well :]
Impressed by your prescience of following your quest. Watched all the levitator Videos . Gives me inspiration to continue my own projects. Thanks for sharing the honest path of innovation.
not sad at all, we all know the next one is going to be twice as good
A color wing or indicator on each rotor might aid is matching wobble to a rotor orientation.
Regret to disagree with some comments below as lowering the CofG leads to INstability - Flap back and the pendulum etc. ! The blade pitch angles look to be less than rigid as the blade that ended up pointing to the sky went into negative pitch causing the disaster. We should perhaps make sure the c of G of the blade is coincident of the centre of lift to promote pitch stability. So sad to see this early trial end up this way after the majestic serenity of the earlier machines. I suggest further early tests be made with the base fixed to the ground where early rotor instability might be less damaging. Wonderful project, well done !
1. The main mast is not rigid enough: It visibly bends under the loads.
2. There seems to be some degree of coupling between the rotors, leading to vibration, likely exacerbated by: a) the high angle of attack (most of the lift is due to air being pushed downwards, not by a low pressure zone on top of the wing), and b) the rigid bracing.
IMHO, nothing that disqualifies the concept. Just a little tweaking needed. And great project by the way!!
I wonder if ground resonance contributed
Yes.
1. Yes, it does look like it bends.
2. Not sure what you mean by 'coupling'. The main mast couples them and it's bending.
Great effort!! Some observations: 1) Central support mass needs to be stronger -2) Lower center of mass needed (add weight at base) to add stability?? and -3) Turbulence from the wings/flaps are creating instability between upper and lower rotor assembly. Good luck!!
lower center of mass doesnt work on drones
2. seems like the pendulum fallacy.
@darkevilapie this is not a drone, it's a helicopter
Pretty much my thoughts too.
i may be wrong but i feel like the main advantage of a coaxial rotor setup is the torque cancellation effect. but in your case since you are driving them with the tip motors you dont have any torque to cancel so you are left fighting the disadvantages of the coaxial setup, ie vibration from the lower blade interacting with the wake from the upper blade and double the part count. i think you were on to something good with your earlier single rotor design and i bet with incremental improvements you could make that one fly really well. i wish you the best of luck whatever you decide to do!
I see at 8:19 the center shaft broke. You can see the top part is different then the bottom half.
was the control simply out of phase?... one side lowered, and then the blades seemed to go negative pitch even more dramatically the further it leaned before the blade flex/collision. These are such groovy machines, I look forward to the improvements!
You will have this figured out in no time…..!!👍🏻👍🏻👍🏻👍🏻
Looking forward to watching this beautiful majestic machine fly at your will …….!
So sad to see it crash.
might be some resonance, you have 2 rotating assemblies that weight around 45Kg each, and they're held together by a pretty thin tube
Вы уникальный ! Сами реализуете такие проекты.
Это требует много времени и усилий. Невероятно!
With an even number of blades, the opposing forces would cancel out and will be less deceptive to the turbulence from the other pair of rotors.
More blades might help to produce a more constant thrust maybe
Wonderful! Thank you so much for sharing your experiments, it is very generous especially to share your disappointments. I hope you don;t mind me venting some ideas.Imaging two control surfaces in front of each propeller, vertical and horizontal able to define the circle and combat wobble. Each propeller unit has its own sensors and could be thought of as one of 6 planes flying in formation. The pitch of the main propellers could be controlled by a separate system. The canards of each power unit would have the leverage to have more control. I think they could control wobble in every direction. Thanks again for this great channel!
I'm sad that your recent attempts have had disappointing results.
Since tip propellers don't generate reaction torque, there seems to be no advantage to using counter-rotating propellers.
But new attempts are worth trying because you never know until you try.
Your bold attempts excite me!
Agree that it seems to be the spine flexing that's the root of all your major woes, it's got a lot of asymmetrical forces on it and can't keep the rotors parallel as well as it should. You can hear the thrust props collide before the crash itself occurs because the spine flexed and the clearance was closed. Still a promising design though, much more scope to scale than the first levitator imo! Think of the wingspan a single rotor design would need compared to this design. The original levitator seems so good because it had a lot more development...
I see courage in your willingness to experiment, in your objective assessment of the outcome, and your decision to move away from unsuccessful approaches rather than being invested in them. I look forward to seeing your next steps.
Balancing such a large mechanism without NASA level engineering is a challenge, so some structural compensation would seem to be required to handle negative vibrations. 🤷♂️
Balancing should be as simple as attaching half of the machine to a bearing on a wall like a wheel or simply putting on its side on a stand that is attached to the axel, the heavy part will spin to the bottom and weight needs to be applied to the opposite side then it's rotated let settle and repeated.
You can achieve quite good balance this way the limiting factor however is the drag or friction of the bearing this affects the "resolution"
I don’t get why you put all the heavy stuff like batteries and controllers into rotation when you’re having slip rings anyways? Must be a nightmare to balance that and even then, any change of load on the wings would bring this out of control?
Wouldn’t it be best to place all the heavy stuff on the axle to have also a stabilizing momentum there?
Anyways, nice project again. I am watching!
Great to see you posting again. A thought,,,, could you run a thin steel cable from wing tip to tip, creating a tensioned triangle to help stiffen
the structure and maybe a way to balance the prop.
I've had a vaguely similar design in my head for a while only using hub motors on a single shaft.
The "foot " is tiny, especially for the testing phase
At the beginning of, during spin up, there’s a neat optical illusion going on. I couldn’t tell what directions the blades were rotating…sometimes they looked like they both were rotating in the same direction.
Love your innovation and diligence! Future testing might involve a central axle, which slips into a tube, mounted in the ground. A bungee of sorts would prevent axle form escaping the tube. This would allow for lift and balancing without resulting damage to structural framework. "Nightflyyer" (on TH-cam) made a support, like this, to pre-flight test his RC helicopters. I followed his method, and made a couple of my own to test the RC systems... Tx and Rx, prior to free-flying, learning that some folks have released models to the air, only to have them fly off... never to return.
Nice to see you back 👍🏻
Ok. As a model builder. First build small. Make changes on a small model. Redesign as problems occur. Make it as light as possible. Test. Get it to fly. Test. Train yourself to fly that model. Prove it works. Build bigger. Test. Prove it works. Build bigger. If you can make the small one fly you can make the full size one fly. It saves a lot of time and money to start small.
I think that that is an excellent suggestion. The ‘wobble’ at startup, perhaps instability is a better word, should have been easier to catch and correct with a smaller (much) model, as opposed to the crumpled heap on screen. Excellent idea.
Every failure is progress :) I think that with a rotor powered like this that there is minimal torque on the main body of the aircraft. Therefore I would pursue a single rotor design from now on. I would also have the batteries and electronics located in a fuselage below the main rotor to give more pendulum stability. But hey I am just sitting here typing ideas and not actually doing the real thing like you are. Respect to you :)
I love these machines and think they are beautiful and could be used in a lot of interesting applications... keep going! dont give up!
8:11 it flies
Take it from Bob Ross there are no mistakes only happy accidents, what a great opportunity for groth and new creative ideas that stem from this little accident next versions are going to be even better
I can feel this is leading to further adventures in aeronautics. It's too easy to let things bring you down, but when you can analyse your footage and work through the physical courses it can lead you to future breakthroughs and better futures.
I wait with anticipation.
At 8:24, the skid touches the ground. This sets off a chain reaction of events leading to the rotors colliding. This is an issue with full size copters as well -- bad things can happen when the pilot doesn't get it clear of the ground and the skids touch the ground. It sends a vibration that escalates and completely messes up the rotation of the main rotor.
Always tough when a design have high hopes for doesn't work out. But, you have the attitude! My immediate thought was that the rotors found the resonant frequency of the main structure and shook it so hard it that the central column bent.
This thing is awesome man. Please keep going.
Very cool! Like the first one worked better. What if you made a chinook style one it would have a large footprint but easier to build?
Maybe you can build some kind of testing contraption, where it can only move up & down while being supported! Like on a vertical wire or metal rod/pipe **insert metal pipe sound** going through the middle 💚💚
had to pause to rewatch that skit. such gold!
Do your rotors have cyclic pitch control or?
I love your work, thank you! If you made the lower part, the bottom of the stand heavier than the top part then it will stabilize much easier while creating a safer landing. So you could for example place the batteries at the bottom point of the design. Hope to see more of this and that there are some kind souls out there that can help with a little financial support. 👍 Maybe if you skip the main battery pack, just use enough batteries to maintain a stable flight and make the wings covered in solar cells. 😅
Man reinvents the square wheel.
Looks like it bounced on the ground on the side near to us and that caused the upper blades to collide with the lower ones since the central pillar essentially bent (probably a lot more force on it with the propellers moving than stationary). Check elastic limits/flexibility under 1/2 the weight of the whole system and with a lever effect of the base support at the bottom of the lower prop connection. I think using 2 or 4 blades would provide more stability in the interaction when the blades cross each other, since the opposite side relies only on the interaction of a single prop and not two which could amplify problems...
Really disappointed for you, all that work with little reward but it did look pretty cool while it was spinning. plenty of salvageable parts for the next version. Coaxial's hey, over complicated and troublesome. I wonder if the central tube was the first thing to bend causing the crash. As we know without hinges on the rotor gyroscopic forces are transferred from one rotor to another through the connecting tube.
Looks like it flew to me for just a little bit test number two... Fantastic machine
This is an awesome project.
Every time a paddle from the lower rotor comes around the front, the back of the base lifts off the ground. Def a balance issue. Can not wait to see it in the air tho. Its beautiful! Looks like something straight from Ds Vinci's workshop!
Rule # 1. As I was learning to fly RC copters, to prevent tip overs I attached X shaped sticks to the skids with wiffle balls on the ends to keep it from tipping over if the trim was off. That way I could start a liftoff without fear of tipping. Adjust trim and try again. CHAIN IT DOWN so it can only rise a FOOT. Adjust and try again. If it tries to SCOOT in ANY direction during liftoff, start over. Tweak and try THEN set her free.
That's exactly what I was going to recommend
keep going, i look forward to the next design.
sorry for the mishap but we always learn something out of it...
Too bad. Looking forward to your next crazy idea.
...on that note - Using three of the single rotors arranged in a triangle (like a quad drone, but tri) with a seat in the middle might be interesting. A bit like to one you did with the dozens of drone motors and props. I would be fairly stable I'd imagine.
Perseverance will be rewarded!
one of the control links broke.. the angle of attack goes to negative pitch. right before blade hits the ground. You can not see the mechanical failure, but you can hear it happen right before the blade goes negative pitch
Wonderful... maybe only one rotor should have active gyroscopic stabilisation? You might be getting destructive coupling between two active control systems.
That is pretty rough, I wonder if you had some sort of structure to hold it in place. Maybe a large metal pole to support it from might help in case it develops an unstable oscillation, or if there is some sort of roll torque due to the propellers spinning?
I may be wrong, but I believe that there will always be forces in the design that take the axis away from the vertical position. And there are devices that easily solve such problems. These are gyroscopes. Probably you will need two gyroscopes - in the upper and lower parts of the axis. Возможно , я не прав, но я считаю, что в конструкции всегда будут силы, уводящие ось из вертикального положения. И есть приборы, которые легко решают такие проблемы. Это гироскопы. Наверное нужно будет два гироскопа - в верхней и нижней частях оси.
Everything was swimming until the prop grounded a touchdown.
Robust chassis, debris guards, some redundancy... next steps!
More ridgidity old boy! You do make great projects.
Getting my popcorn ready... 😂
Slightly off topic, but... what is this new coating you brought to the airfield?
wish i was like u
8:10 it seems like there is deflection on the mast that starts with deflection to the left as viewed from the screen.
It's hard but ideas help with our need to express ourselves. A gyroscope will help stabilize the craft. It's not about weight but rotational inertia that makes the gyro effective. Like a bikes wheels. Hopefully this will help. Cheers and keep up with your efforts.
The blades are not geared together so it's inevitable they will go out of phase, leading to vibration/ instability.
Somekind of large bearing between the two riggid propeller units could help
08:17 Main shaft is bent between two rotors. In couple seconds there is a sound of crack.
I think you broke a pitch link causing that cracking noise on the lower blade that is at the back at the time. You can see it invert as it comes around and drives the craft over. I feel for you after an obviously laborious build. Thank you for sharing this journey.
Very cool project. I don't know enough to give any constructive feedback other than setting up more cameras at different angles would give you a lot more to review and learn from. Keep after it and thanks for sharing!
Hi there.
I know its been a couple months, but I also watched Your video over and over ... and over again. If You are still trying to figure out why it went wrong, I think I actually see exactly what happens the first second after the cracking sound. Also I dont think stuff breaks at 8:19 like someone suggested. Anyway..
Set Your TH-cam speed to 0.25 to verify or disagree with my findings.
Navigate to 8:20 and start video, breaking sound at 8:21.
Now pay attention to the lower prop blade that is just about to go behind main shaft.
When it appears again the pitch on this one blade will go from positive to really negative in halv a rotation. This results in this blade's lower support rod being bendt heavily as seen 8:24-8:27.
I think the reason for the breaking sound was Your mechanism to rotate(pitch) this spesific wing breaking.
I got some experience from building/repairing rc helicopters for customers earlier, and things not perfectly straight will always vibrate a lot on the ground. Usually a lot of the vibrations and shaking on the ground will go away once properly in the air
It's such a shame we could not see this fly properly before the crash. 😢
Out of all your videos and Finally a Failure. Proof your are not a god.
Seems like the center of pressure was too far back, the blade fluttered, and the whole thing tipped over.
It seems to be caused by the cushioning between the two nodes. It seems to be unable to withstand the lateral load and a sprain occurs. My suggestion is to increase the diameter of the middle node and use bearings between the two bodies. If there is a spine that extends along the entire vertical line, pass it through the middle of the entire structure.
A very successful product. Congratulations.
Just analyze the weaknesses and the strengths. Learn from it all. There’s a treasure trove of information in that hop and the crash. I think the pop was either a prop strike or one of the blade tubes kinked at the root. Just guessing. You’re right about the blade tube weakness. It’s the root that takes the brunt of the load. Make the disks larger diameter to support them better. Also the larger disks will provide gyroscopic stability (like flywheels). You’re doing something amazing. Keep it up. The goal is definitely reachable!
I coud feel the gravitional waves all the way here .-.
She was trying so hard to stabilize. Best of luck on future projects.
At 8:23 8:24 it seems like the front of the lower rortorblade to the left in view, is angled/tilted downwards quite a bit.
Whilst the Levitator 3 cannot fly fast horizontally it can fly a parabolic path. ie. Climb upwards whilst pitched forward. Still a big success in my view.
Opinion... it appears a loss of stability caused a loss of lift and hence contact of the blade systems, after touching back down... so perhaps the central shaft needs to be a three legged design (like a radio tower) with hubs for the prop mechanism to rotate on, creating more initial stability during power up... and maybe some load added to the landing leg. 🤷♂️
My layman’s observation.
👣🕊👽
That's how we learn ✌
I hope there was not to much damage.
Looked as though one of the lower blades was pointing down @ 8:24.
nobody like failure, but sometimes we can learn from it.
😮😮What I don't understand is why it doesn't have a landing gear that's infinitely more stable, with more projected surface, so that when it destabilizes, it doesn't lose balance and remains stable on the ground. Right at the beginning of the video, it was clear what the fate of this beautiful aircraft would be.
The crash makes it look like it was blown over. I did not hear the crack, but that must be at the heart of it. 🤔
I suggest as long as that central mast is wavering you will not fly successfully. Good luck!
I think that by making the legs of the tripod longer, it could help avoid crashes during unstable takeoff.
Ваш эксперимент был интересен,спасибо! этот момент действительно -путь к дальнейшему.Как мне кажется,во вращении ротора не хватало стабилизирующего гироскопического усилия.В радио управляемых моделях соосной схемы устанавливают гироскопы,у вас тоже соосник...
Looking at it frame by frame it appeared to me that after it started to list the main tube (vertical) looked like it bent between the upper and lower and allowed the upper rotor blade hit the lower blade.
Due to the buffeting inherent with counter rotating props they need to be either extremely narrow like helicopter blades or short and rigid. Also, move as much mass as possible to the bottom of the rig and decouple it from rotation so your fighting as little inertia as possible. Just suggestions, hope it helps!
There's a reason helicopter blades float freely around the main spindle. I think You'll need the same feature.
I thought of this a long time ago for the human powered design! Your drive propellers should be Position in the spar support location witch will give higher rotational speed. But you need to consider better weight and balance to keep vibrations down.
Carbon fibre or titanium?
Seems premature to give up this guickly.its facinating to watch.also did you think of shortening the cables on the single rotor the install a low tension sppring in the cable ends,
to effect a small amount of flapping effect?
Kinda hard to keep track but I'll say you got a sync issue on top of a slightly off vertical shaft, before the crash.
It would help to distinguish the blades. Color coded, different patterns, numbered or whatever. You need to easily tell when top and bottom are out of phase. Looked like the two blades I was tracking met about 30° early then it started tipping.
Starting to wonder if a faster µcontroller would be a quick fix, after the rebuild.
So, just a couple of suggestions.
Looks like you need a ballast weight in the bottom to help stabilize the craft. All of the weight is up high, and it's top heavy.
Also, it appears that the rotors spin independently. Have you considered locking the rotors by adding a planetary gear in between? I feel like it might help with rotor synchronization if you did so. You should still be able to affect lateral rotation by powering up one rotor vs. The other, but it would lock blade timing. I think these two changes would yield some better results without changing the entire design.
Don’t you need more weight at the bottom to stabilise it? It is like trying to balance a broom (including the mopping end) on a finger tip.
I thought, based on the nature of the sound and the wing positions at the time, that the Crack sound was two props striking each other?
I'll be back for the next one
Would slower wing would improve such violent shaking, these ‘flat sails’ didn’t provide so much lift.
P.s. I kept thinking this was black and white, then I saw the grass was a green shade of grey.
Maybe a bit more saturation?
Make a turning circle surface in the center, stronger and stops center air updraft.
Outch. Sorry to see that.
Any particular reason for contra rotating rotors?
You are producing torque on the rotor tips so minimal torque effect feeding back into the system.
The main structure is bending a lot. I’m thinking it is because when the wings move relative to each other the two different wing structures cause different lift vectors depending on how they are rotating relative to each other. If the main structure that the wings spin around is more rigid that would be prevented.
A bit of a guess granted. But it shouldn’t be bending like that
Might be upper main mast making that noise at 8:21 - upper rotor bending the main shaft between 8:21 and 8:30