Coaxial Levitator 2 First crash....
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- Опубликовано: 13 окт 2024
- This configuration of the levitator turns out to be a dead end for me.
-Which quite frankly feels more like a relief than a defeat. I have gotten too far away from the original concept of the beautiful simple levitator.
😭
Thanks for sharing. The best of luck with your future developements. Even the failures are worth the watch.
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
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!!
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 !
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!
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.
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!
A color wing or indicator on each rotor might aid is matching wobble to a rotor orientation.
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.
So sad to see it crash.
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 RUclips) 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.
I see at 8:19 the center shaft broke. You can see the top part is different then the bottom half.
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'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!
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
I noticed that the top and bottom blades would align at two different phases of the rotation. Because of the changing angle of attack during one rotation, at one point where the wings align, we would see the top wing have an steep angle of attack and at the other alignment point, the bottom wing would have a steep angle of attack. When the top has a steep angle of attack it pushes away from the bottom and when the bottom has a steep angle of attack it pushes into the top. That's my guess why the oscillation happen.
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.
You will have this figured out in no time…..!!👍🏻👍🏻👍🏻👍🏻
Looking forward to watching this beautiful majestic machine fly at your will …….!
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!
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 💚💚
might be some resonance, you have 2 rotating assemblies that weight around 45Kg each, and they're held together by a pretty thin tube
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.
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.
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!
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.
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
Вы уникальный ! Сами реализуете такие проекты.
Это требует много времени и усилий. Невероятно!
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.
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
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
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.
More ridgidity old boy! You do make great projects.
had to pause to rewatch that skit. such gold!
Wonderful... maybe only one rotor should have active gyroscopic stabilisation? You might be getting destructive coupling between two active control systems.
😮😮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 blades are not geared together so it's inevitable they will go out of phase, leading to vibration/ instability.
Everything was swimming until the prop grounded a touchdown.
Robust chassis, debris guards, some redundancy... next steps!
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...
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?
She was trying so hard to stabilize. Best of luck on future projects.
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!
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. 🤷♂️
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.
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.
👣🕊👽
Seems like the center of pressure was too far back, the blade fluttered, and the whole thing tipped over.
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. 😅
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!
Out of all your videos and Finally a Failure. Proof your are not a god.
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.
Nice to see you back 👍🏻
This is an awesome project.
wish i was like u
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...
If it were easy, anyone could do it. Keep the courage!
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!
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.
keep going, i look forward to the next design.
Hovering is not flying forward... Figure out the dragonfly... Backpack, human sized... You're a trillionaire...
This thing is awesome man. Please keep going.
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.
I think that by making the legs of the tripod longer, it could help avoid crashes during unstable takeoff.
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.
Getting my popcorn ready... 😂
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!
Slightly off topic, but... what is this new coating you brought to the airfield?
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!
There's a reason helicopter blades float freely around the main spindle. I think You'll need the same feature.
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.
The "foot " is tiny, especially for the testing phase
Make a turning circle surface in the center, stronger and stops center air updraft.
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?
You should use a crane / lifting security cable to avoid this kind of crash, Keep going!
Somekind of large bearing between the two riggid propeller units could help
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
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...
yeah the single rotor design was much more stable. stick with it, your results are amazing.
keep up the good work and don't be despondent old chap, remember, nothing ventured, nothing gained! .
Sorry to see you had a crash!
I think it is getting too complex and probably too heavy.
Maybe keep the top rotor large and tri-motor as the main lift motor, then reduce bottom rotor in diameter and make it simpler and lighter with no control surfaces or propmotors on the bottom rotor. Maybe just a motor and reduction belt so the bottom rotor can be turned as needed to keep the payload non-rotating, and maybe get some lift from the bottom rotor too.
Scrap everything, and start over... Hummingbird... Dragonfly... Or look for a taller cliff... Hint: your center of gravity is too high.
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.
Helicopters color code each blade to make balancing and phasing easier to see. You should use some kind of colored surface to identify each blade.
That's how we learn ✌
Just off the cuff. Have you thought about have rotors syched with each other? I think it might be sympathetic out phase oscillation. One other being out phase is uneven lift occuring.
Excellent improvement since Lev 1,2,3 and your beginning. Your flight test location needs a flat surface ie. concrete and the basic tripod for 100kg needs wheels or round bearings so it slides rather than catches, like a helicopter moving sideways does. I still think moving all the batteries to the baseplate and sharing their power via sliprings to the wings would give less rotating inertia and less problems as you move sideways. Why are you not using a long elastic safety band for these tests just to give 20m safe flying space over the take off point. Whatever your decisions are you have to continue and improve, we all really need this in our lives. david
The "crack" sound originated from "not flapping" enough... More flapping!
I hope there was not to much damage.
Looked as though one of the lower blades was pointing down @ 8:24.
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.
I'll be back for the next one
Are the wings perfectly balanced, so as not to produce "wobble" going around.
Before reading comments and hearing your explanation, I thought it might have been a freak gust of wind.
How about some weight in the base to help with stability during the first trial phases?
It looks like you expect it to hover somewhat stably. It can't for the same reason a helicopter won't hover if the pilot holds the stick perfectly still.
Very Good! ~ You needed some balanced weight on the bottom basket area..
put all the bulk weight at the bottom and come up with some kind of power transfer device.
Slip ring?
The opposite may be better...increase the phase margin. See Rotorcraft Stability-Phase Margin Requirements in Hover
but on the plus side you werent in it!
I think more ballast weight at the base is needed to ballance out how top heavy it is
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.
What would happen if a large thrust bearing, like that used in a TV turntable, were used to suppress the up and down rotational wobble?