This is my favourite content, hands down. I love experimenting and pushing things forward. Seems like all people are worried about these days is can you smash something into concrete at 100 mph, regardless of whether it flies like dog water. I have no interest in that whatsoever. Thank you for taking time to make these videos, you're obviously an incredibly busy person. 💪🏻
You're at the forefront of the hobby Bob, we all appreciate the massive amount of work you put in to advance it forward. I remember coming up with ultralight quad theories as a teenager, waiting patiently as the years ticked by and there were incremental improvements in all aspects - you can only imagine how excited I was when you began releasing your work on the Toothpick. Thanks for making that dream a reality!
@@BloodyJMF I'm getting close to considering an HD toothpick deal soon I hope. The components are getting really good. These dampers will definitely be involved with that one. I just wish the aio boards weren't so darn expensive these days.
@@Kabab I'm kinda lucky we bought them in packs of fourty from JHE back when. Since we never really managed to break stuff we still have them together with all the replacement arms xD
I’m a machinist for 3 lumber mills and I learned a hard lesson quickly. Rarely do you solve a problem with brute force. We had the arms that lift up the boards. Thy are cycled with air cylinders. Theses arena where made from steel tube. Thy kept breaking them. So I made some out of solid plate and now the problem moved to the cylinder mounts and started ripping them apart. So I made heat treated mounts. Then we started loosing cylinders so we went up in rod size. Then the entire frame started cracking and puking out of the concrete. The solution was making arms out of solid UHMW and we have never had a problem since. Heavy objects don’t want to move and stopping them is even harder. So dropping weight and moving to a forgiving material solved it. I have seen this trend with frames getting stiffer and stiffer. The stiffer something is the more effective it is going to transfer vibrations. Think a pre cooked vs a cooked noodle. But this is a rabbit hole that is very easy to go down when you think we need more strength and more and more. When like you said mass does not want to move so bolt the FC to the biggest mass you have and isolate it from the rest of the frame. I’m surprised dampening motor mounts have not been really developed.
In this specific case, it's not quite consistent with your findings with your application. I have tried to make arms from HDPE and a number of other materials as well as sandwiched materials and many other options just to run into low frequency wobbles and resonance which is the very worst kind of vibration for this application. I do hear you completely however and will try something else you may be intrigued to see in the future.
I’m taking a break from FPV right now but man this excited me. Innovation has kinda been stagnant lately, or at least stagnant in the departments I find interesting so this was sick!
Unfortunately a lot of that has to do with how the world has just halted for the past 3 years. At this point I wouldn't even say it's a result of COVID. I would say it's more so as a result of both of our idiotic governments. Unfortunately small businesses end general developments suffer as a result
@Kabab not to mention studies that are confirming cognitive issues are more than common after a Covid infection. Some level of brain damage comes along with every
Also on a break and being gaslighted from this! Got to the point where I was burning flight controllers out once a week bc of bad gyro QA. Not sustainable
@@Kabab hey buddy, i spent a couple decades building digital models of acoustic musical instruments. i've designed micro frames like the deculture fuxxor but you know everybody wanna be famous. ..understanding waveguides, take some of your carbon and cut it into strips or use plates and measure the impulse response over distance. the reason is, very simple models of acoustic instruments focusing on only the lower partials are "often correct enough," so if you design a frame by having solid data about the impulse response of your material so you can design at least the first order responsivity of the dimensions, you can at least improve upon the most elementary criteria. but seriously, you go about it all wrong like everyone else. if you want to minimise vibration, don't clamp it on with a steel U bolt... use dental floss. if there's no mass, there's no vibration. glue and dental floss will actually make an awesome lightweight frame and it has all the tensile strength you could want. yeah i wish some people had spent time listening to me instead of trying to be the next instant celeb. i tell people useful stuff. like if you need to code a cepstrum from your fourier analysis, just run another fft on your mag10'ed mag bins :)
You randomly showed up on my feed. This is the first video I have seen of yours and I've actually re watched five times since. Thanks for pushing the industry forward and I am now subscribed.
We promise to floss and appreciate lower production videos as long as you keep the awesome updates coming. Love your exploration and persistent trial and error approach sir.
Bob is one of those few guys who pushes the industry forward, he figures something out, then the rest of community catch him up after 1-2 years. From my shallow experience what I found out was - for high performance 5 inchers sometimes it's better to reduce the filter (faze) delay but get some more noise, than get the absolutely clean gyro traces after filtering. PIDs should act on the gyro signal which is closest to the present time. It's good to have frame resonance higher than 200hz, then to cut it out with either static or dynamic notch. Sorry for my generalizations, that's related to my build.
You rock man. We need more innovation to come back in this hobby. I loved they hayday of seeing different solutions and frame design. Keep chugging away man.
He does it again folks! Again and again and again and again! The man, the myth, the MF Legend!!! No one is like you in this hobby, especially after all these years. Cheers to you my friend. 🎉🎉
😂 I always use BB. I just don't put a whole lot of effort into dissecting it because it reminds me of my organic chemistry lab exams where we get a similar graph and need to explain which molecule we're looking at which was so annoying....also because you can go so deep into it and I'd rather focus on high level ways to get things working right without fuss. I use your presents in BF all the time. Sometimes they match right and it's better. 👍
@@Kabab yeah it is just a good tool. Don't be shy. Embrace the obsession. My take is there are lots of frames out there that work well for vibration across all the quad classes. If we narrow to 5" class, that probably has the most: Apex, Martian II, Trans Tek Laser, Source One, etc... The gist I'm gathering is you want less weight and that is then where the vibrations creep in? OR I think you just have some engineer in you, because this video is like the engineering method 101: design, build, test, measure, modify, repeat. Tools like finite element analysis can shorten the cycle, but can take the fun out of it when the hobby is the method, not doing the finite analalsys in front of a PC; which then also needs real-world validate (is a part of design step). Mark Spatz, P.E. (licensed) (in good company here 😎)
@@uavtech I definitely prefer and enjoy the build-test approach. Moreso because I learn a lot more about other things than just what I'm trying to focus on. FEA is helpful but is a very sterilized approach which doesn't always lead to the right result. That and I'm definitely looking for a way to drop weight. 20g less with comparable or better vibration management is gold to me.
@@uavtech Really is amazing how well the source one v3 performs stock and its even better if you move to 6mm arms its dead quiet in the bb. I've got some far more expensive frames that resonate all the way up to 300Hz.
Fascinating stuff indeed, Bob! Fascinating testing! 😃 But you were spot on when you mentioned that the plate with more mass vibrates less. As more mass, more energy you'd need to make it move at all. Anyway, stay safe there with your family! 🖖😊
I’ve always wanted to attach the FC and camera to the battery, the least vibrating mass on the craft, and then isolate the motors, by putting hem on the other side of the battery mass. Pretty much strap the camera and FC to the battery, and then strap that to the frame/motors. Sticking it to the top plate is something I’ve always thought made sense as well. Great to see you do so much research in all these different avenues of possibilities. Thank you for sharing ythis. It’s so educational in so many dimensions. Yes! Faster videos, less production value is better if you can share our findings faster. Great video! You have one of the best presentation skills in FPV. Quick, concise, relevant, good pace, actual knowledge, etc.
@@Kabab I guess one can make a simple test by printing some lipo guard, sticking it on top of the battery and just duct taping the FC to it. Not production ready solution of course, but should be enough to estimate if this particular spot gives better results.
Thanks k you for the work you do. Please take the time to upload your findings to RUclips, I think it is really beneficial for all the flyers who see you videos and are also experimenting themselves
mounting the fc near the main mass of the quad seems such a good idea, mass is a crucial element in vibrations absorption so we should indeed play with it
Cool video, a lot of really interesting concepts in there. From my experience and simulations I can't really find a way forward with rubber damping parts except for lightweight components with gyros that need vibration isolation for higher frequencies. If you try to soft mount heavy parts (like go pro or battery) you have two heavy bodies that can move relative to each other with low resonant frequency... Catastrophe! Anything like rubber that is springy as well as damping will create new resonances as well as soaking up energy. The heavier the sprung mass and the softer the rubber the lower the new resonance and the bigger the problem it causes. Soft ruber is good for absorbing vibrations but also causes lower frequency vibes. If we want to "soft mount" heavy parts like Go Pro or Battery we need to use very stiff ruber to avoid creating low frequency resonance. Unfortunately stiff rubber doesn't really absorb vibration! Damping grease has zero spring so doesn't create a new resonance which is why it consistently works. Looking forward to seeing what comes next, keep at it.
i made my own camera mount which mechanically decouple the camera. simple as that. no jello. no ND nonsense. no shaking. perfect footage on EVERY quad with every different action cam. DJI, insta36 or gopro. from 3" all the way up to 6" works. i am trying to convince people for 2 years to try my mount for free. most refuse and say i need change PIDs. or must use ND filters. or other BS. at this point i gave up. my footage is perfect. always. while others still struggle. happy to see you also working on that.
@@Kabab which i can totally appreciate as cinematic pilot. and thats the ONLY way NDs should be used for. but lets be honest 90% say it helps with jello which is right but only like 50% and its a patch for an entirely different problem. anyway as i said i am happy to see others trying to deal with the actual vibration problem instead of just use other tools to cover it. good job
It seems that you should try those new low-noise helical props. Since they reduce air turbulence (and vibration) making them more efficient and quieter.
I literally put a video up on that this morning. All those claims are false by MIT unfortunately but the overall prop design that was made may not be a total waste. See the video I put up this morning
@@Kabab I watched it. That kind of propeller design is a whole new area to experiment with and make videos. About frames: Have you looked into making frames with a biomimicry structural design? They are of course difficult to design and produce, but I think that method would solve your vibration issues, as well as make them lighter. Another drawback is that you'd have to add plastic skins over them to reduce drag. (I looked through most of your video thumbnails, and I didn't see any.)
I’m simply interested in what ideas you are playing around with. A basic one take vlog style with you and the prototypes , cad, etc and little to no editing would do it for me.
My motorcycle handle bar uses an internal brass rod with o-rings to dampen instead of a heavy weight at the bar end.i wonder if a similar concept would work next to each motor
I reduce the vibrations in a slightly different way. I modified the betaflight configurator so that I can see the unfiltered vibrations on the motor as it spins from the configurator. The quadcopter is anchored not very hard, but enough not to fly away on soft material. I rotate the motor to a certain speed, record the maximum vibration amplitude and stop the motor. After that, I add a little adhesive tape to the propeller and act according to the method for worse or better. Thus, it turns out to reduce vibrations several times even on new motors and propellants. On my old gopro 3, this reduces the effect of jelly to almost zero.
Jello isn't the issue here. It's the vibrations getting to the gyro. What you do is dynamic balancing and the best way however it's very time consuming and doesn't last once you damage a blade a little or swap blades or even just unscrew and tighten a blade.
@@Kabab I tried today to change the flight controller to the top plate for the sake of interest. Without rubber dampers on the top plate but with dampers on the flight controller. According to the logs - it got a little worse. So apparently there is no difference in person closer or farther from the battery.
Someone really gets engineering when they say, "...generate heat from vibrations." Armed with engineering knowledge and experience, you open up solutions that are fantastically innovative, like braided wire for dampening, and in my field, eccentrically-braced frames which bend steel beams to generate heat during an earthquake. Like brakes on a car to dissipate energy, it's all about energy transfer and ultimately intentional heat generation. Friction, elastomeric materials, plastic deformation of ductile materials, even fluid turbulence all do the same thing at the end of the day.
Interesting! I had tons of oscillations in my last kwad to the point where I now sell it. Would be great to see an overall performance improvement. Keep up the good work!
Excellent video my man! The smoothest quad I’ve ever flown to date has been my current catalyst machine works BangGod. Tbh I’ve flown many different quads and if they all have the same motors and props and 6s power, they all fly so similar once tuned correctly. I stick with the banggod because it’s the first quad I’ve had that is damn near indestructible.
How does adding a crossbar compare to doubling the arms in terms of vibration reduction/weight? Would be interesting to see this comparison on h-frame with sidebars and an x-frame with front and rear bars
how you played with SpeedyBee Master 5 HD Frame. The whole FC is mounted on TPU section in the middle of the body. BTW. I been experimenting for last 2 years with same issue you are describing. You will find that carbon tubes as arms cut down on vibrations significantly. Maybe combining speedybee concept with CF tubes would give us interesting results,
The speedybee system is not much better than the rubber grommets already built into the FC. It may help a bit more. Probably doesn't hurt since the stack is generally low weight and hard to oscillate. I may pick one up to see how it is
@@Kabab Reckon you are doing your fair share to make a big difference too. Not to mention improving FPV pilots orsl hygiene 😬 I hope BlackOut reads this encouraging message.
Inspiring video! How about designing a frame which would have a room/compartment in the centre to mount the battery? The FC would be installed in its own carbon cage (to protect it from crashes), which would be fixed directly to the battery, independently of the battery-frame mounting. This way there would be a physical isolation of the FC from the frame with the battery (being the heaviest component of the quad) acting as the vibration absorber, separating/isolating the motors/frame from the FC..
That would be really nice but we're working with a weight restriction here. It costs a lot in weight to make different components inside. Especially for the battery. It's also very difficult because no battery is the same size and they change size over their lifespan too
wow love the thorough testing you do. When you said the idea was basically to have the flight controller closest to the main mass of the quad so you mount it on the top plate - what if we just mount the battery on the bottom plate? maybe having the center of mass so high above the prop line is causing these vibration issues?
The problem with moving the batt to the bottom is that the quad then flies different. This is how race quads mount their batt because they crash often and batt on top is destroyed in most crashes. Weight distribution is one of the most significant factors in a quads performance
100% Silicone calk/sealant sandwiched between frame components does wonders to reduce the noise floor. Because it's a mild adhesive, it seems to really unify the frame pieces. It's better than greasing it because it sets up and doesn't constantly ooze out and attract dirt.
Yeah that's an option but it suffers from the same issue as anything else between carbon. You bolt it together to try and keep it strong which negates anything between mostly
In long range shooting, people tune their barrels to reduce vibration by having a mass near the end of the barrel that they can adjust the position of. Maybe having a small and movable weight on each arms can help reduce vibrations when you adjust their positions?
That's a very very interesting idea but it would directly impact flight performance too. I actually do believe it would work however. I just never thought about it.
The whole idea is to decouple the vibration from the motors. The more material the vibrations need to travel through, the more damping you will see, hence why moving the FC to the top plate has more of an effect because the vibes have essentially more distance to cover before reaching the FC. Think of all the mounting points and the material between them as conduits for conducting vibrations. The further your mounts are away from the source of the vibes, the more of a damping effect you will see. Configure the build like a maze where the vibes have the longest path to travel before reaching the FC.
That's where the H frame theoretically makes sense. However I think you'll loose a lot of stiffness and overall rigidity in the whole structure that it creates new problems like lower freq vibrations and more critical resonance modes. So trying to balance that trade-off, you kind of end up with the standard X frame. Just my assumption. We'll see how your test works out
@@ariafpv It's less about X or H shape and more about the interfaces between parts IMO. I'd first focus on building a rigid structure for the arms and motors to have a solid foundation. From there you work backwards and come up with a clever way to decouple that from whatever part your FC is mounted to. The FC mount doesn't need to be strong in itself, it just needs to hold in it's place.
@@KevPV yes kind of what I meant. With X style I was just refering to a standard layout creating a rigid core in the center (opposed to the H frame he showed). Doesn't need to be the usual 4 interlocking arms. As you said the goal is to only have the FC be "decoupled" from the rest
Food for thought for you. The greater surface area that dampening material is able act with the more effective it will be. I suggest three or four milimeter neoprene foam.
Curious if you’ve tried KISS before. They recommend hard mounting for best experience and was wondering what your thoughts on flying it are. Thanks for all the good research you do!
I don't have a lot of experience with kiss but a direct hard mount is better sometimes. The rubber grommets have a lot of bound to them and can be excited by some vibrations leading to much worse vibrations. Not usually however since the FC is usually very low weight. The frequency is usually very high and not approached by most crafts.
Good to see innovation, good luck! In your experience, do side braces help with arm torsional vibrations? In other words, can a box frame be better than X?
Right that is something I've requested from manufacturers on and off. I think it could possibly open up to more options but really what we need are a few gyros mounted to different areas on the craft. Then code that will sample all of them to get tht best data. Or, just deal with the vibration peaks really. The general noise floor just needs to go down a bit.
Cool stuff! What if you took some of the rubber damper things and mount them on the arms, just like on the bottom or top but not sandwiched with anything 😮
Have you tried putting a ballast or weight like square brass with 30x30 holes on top of the flight controller stack with those dampers to change the frequency of the vibrations?
Compound bows have lots of wierd stuff to reduce vibrations. Sometimes the stabilizers have a weight on the end with a very soft rubber between the weight and the rest of the stabilizer. So now I'm wondering if a rubber tail with a small weight on the tip would do anything on a quad..
yeah I've looked at that. It's like a damping mass on a stalk to manage low frequency wobbles. Unfortunately that's going to impact flight performance a LOT more than it could ever be worth
Are you accounting for the fact that the weight of the batter and rubber dampers due to momentum? Like wiggling a ruler or a fat guy on a diving board? And what about the weight or even the maneuvering patterns in correlation to the frame style?
I think you're talking about new resonance from the mounts allowing for wobbles. That's the reason I made the stance as wide as I could but it still happened. I'm not sure what you're referring to regarding maneuverability
Lets say instead of suspending the fuselage section on the arm section with cables we just have a soft material in-between, it can be whatever tpu, rubber, polyurethane try a set of different stiffnesses. this could be attempted on a lot of different frames by just sticking a battery pad between the arm section and the middle plate. It's similar to chris rossers dampening grease idea but less messy.
yeah that works except that you also bolt the thing together which negates anything put between the carbon. We need the actual material that's damping to also be durable enough to hold the craft together.
Vibration isolation and vibration damping are two separate items. I would consider the rubber devices you have there as isolators. They may provide some damping, but their primary purpose is to provide isolation between the two ends of the isolator. It is also important to consider the frequency range of the isolator and how the mass and stiffness of the structure interact with the isolator. I think this is great and we are only scratching the surface here!
We've been clawing at the surface for over a decade now. There's no surefire way to get any sort of hardware damping consistently. Vibration isolators don't work for anything above 3" it seems. I'm guessing the amplitudes are too high when the prop size gets bigger.
@@Kabab I agree, this problem is not easy. I would like to see more of a focus on the frequencies that mater to the FC and what it’s just ignoring. From my understanding, we want to focus on the low frequency flight maneuvers and prop wash frequencies. When the vibration gets to the FC(gyro) it should be cleaned up from motor noise, frame resonances, etc. Most isolators aren’t going to do that well, the simple rubber ones are going to isolate at higher frequencies and maybe not in the correct axis, and if they do isolate at the proper frequencies they are likely to remove the important information as well. Setting up an isolator test stand might be something to consider.. set your quad on the bench and have a beat up prop and slowly ramp up the RPM and record BB… Try it hard mounted and then with the isolators… try to get enough data for a transmissibility curve… but just trying whatever isolator is available off of Amazon makes it tough. Should we be looking at the other end of the problem maybe? Engine isolation? Certainly the approach for cars and real airplanes…
@@REDhlg There is one way we could do this that could work out best. Two gyros. One hard mounted, one soft. Subtract anything that changes from the hard mount to the soft mount. Everything that's the same overall amplitude and movement is real movement that the FC needs to know about. Everything else is garbage.
In precision shooting competition, barrel harmonics is a big issue and there are several ways to deal with them. The simplest is using a heavy barrel (just like thicker drone arms), this only moves harmonics to a higher frequency, you still have to tune your handloads to match the barrel or use a barrel tuner (movable weight). Another way to bypass harmonics is to have the muzzle of the barrel be constrained, this usualy means clamping the tip of the barrel to the stock, in drone terms this is like having a large structure of thinner struts instead of thicker one peice arms. Now to realy remove harmonics, deaden the barrel, you have to convert the energy, there are a few ways to do this. The simplest is to remove direct load paths, this means barrels with dimples, outside threading and axial holes arround the barrel, in drone terms this would mean the arms would have holes and zigzag edges in so that the forces have to go around corners (aka stress risers). The other way is dissimilar materials, this is like an aluminium or carbon fibre barrel with a stainless steel core, since the materials have different stiffness, much energy is lost transfering the vibrations. This is why carbon fibre is inherently a good damper since it is a matrix of epoxy resin and carbon filament, this is also how cars remove body vibrations by bonding a layer of urethane to the metal pannels.
@@paint4pain of these options, the different materials could be the best one for us except that in our case, we don't see waves of vibrations as much as we do overall twisting or wiggling of components. Waves are approachable with different materials and we still get some of that but the main issue is the odd twists and wiggles. One of the main benefits of the H frame design which attracted me to it is that the frame will essentially have no pitch action vibration wise because there's nothing to wiggle. At least not with the energy given. Yaw won't be a big deal and is seldom a problem, roll is the only issue I need to resolve. The body twisting. That's the only notable mode that's gonna kill it. I have some tricks I'm gonna try....... we'll see
I use Kyosho Zeal for all of my quads flight controllers, Spektrum AS3X receivers, and helicopter gyro mounting with no hardware, it's the cleanest and best solution that I've found to this date for minimizing vibrations.
What specific hardware are you looking for? If there is any it'll be on fpvcycle.com. The frames are just test samples so none of that is anywhere. The most useful item right now that's in stock would be the 23mm short motors which pretty much transform any 3" ducted cinewhoop into an amazing flying craft compared to what it was previously if it has any motor size narrower than 22mm wide.
It would be interesting to see the effects of two pusher propellers and motors (motors and propellers below arm)in various configurations with two standard propellers and motors (motors and props above arm). Two pushers directly across from each other in position 1 & 2 or two in position 1 & 3, or 2 & 4. Maybe I'm just crazy.
I'm wandering in here with no background in DIY drones so I have no idea if this is viable to adapt but it seems worth mentioning I saw a vid on silencing a buzzy take-down bow. The main thing they did was add some adhesive pieces of thin felt on the ends of the limbs and in between where the limbs attach to the handle
Yeah that's an option too but the material is difficult to settle on because anything that's physical will have rebound to it which will often make it worse. It's also difficult to consistently apply
@@Kabab yeah that too, i forgot to mention. You probably know him already. He's based here in the UK. Got his own frame range, and goes in pretty hard scientifically. And no I'm not biased as i don't own any of his frames. Just saying incase you haven't heard of him. 😉
@@k1ortia yes I know of Chris. His work is good however he tends to negate the real world often and believes he can simulate everything. He also seems to think he knows everything there is to know so it's pretty difficult to work with him. A problem which I too have had issues with in the past but life has kicked me in the butt enough to let go of all that. Maybe in time he'll come around too.
@@Kabab Funny you should say that, as iv often thought the same to. It's as iv everything is purely simulation based as apposed to real life testing. I'm glad you've put some new content out though as iv not seen anything for a while, so i shall be watching and continue to watch the future videos..😊
@KababFPV , did You try to talk to some car guys companies that make various PU hardness bushings in car suspensions? maybe they could make various hardness mounts with inserts like M3 or even make a two step proccess and use two different PU`s in one mount ? then it would be possible to to make cone like mount poured over with second PU, all enclosed in small cylinder like shape... ofcourse, much much softer PU`s than to the car bushings...
Yeah I would but I don't know what hardness and I'm not confident the same one will work for everyone or even different air temperatures. That's why I need it to work already before I go ahead and try and improve it
@@Kabab but then, You already use softmounts that have no rating at all and from my experience, those black mounts are lottery since those are mainly made from recycled PU ( so the production facility uses whatever available and then add some black pigment to unify the look), so You`re already in the lottery business ;) take a look at car poly bushings or skateboard poly bushings, these are made with color different shore hardness grade. maybe 3 grades (soft/med/hard) would stadarize the softness/hardness...
@@blazefpv3038 for now, they're only proving useful for the smaller 3" prop size and on a cinewhoop. I doubt even the right hardness would make much impact on the 5". I wasn't seeing any improvement at all. It was actually much worse. Hard standoffs were drastically better. But I'll keep testing things. I might double up the mounts just to see how it goes. If that works then a harder material will work.
I had to print some plastic washers for my motor screws once they were abit to long and the quad ran great after im pretty sure the bolts are like tuning forks if you use plastic washers on the bottom and a rubber gasket between the motor and frame im sure it would isolate alot of vibration at the source
At the beginning of the video I show the soft motor mounts we used to use. They sort of worked sometimes but also made things worse other times. Ultimately nobody can tolerate them anymore because your motor screws come loose and it's awful overall to deal with.
After years of carefully tuning to get rid of vibration and then constantly failing, I came to the realization that most of my vibrations come down to temperature. Not only do the resonance frequencies of the materials (carbon/rubber/gel) change, but also the characteristics of the electronics. Most FC use simple RC oscillators which aren't temperature stable, so they drift. So tuning filters for specific frequencies is completely pointless when you are flying in a wide temperature range. Not only that, if you look at datasheets of carefully profiled Gyros you'll find parameters like "Sensitivity percantage change per Kelvin", "Sensitivity percentage change per Volt" (at specific temperature), "Zero-rate offset over temperature change" and "Zero-rate offset drift per Volt" (at specific temperature). So in my opinion testing of frame vibrations only makes sense if you perfectly temperature control at least the electronics. A common practice to achieve that is to encapsulate the electronics and heat them to a fixed temperature. I don't think anyone would go that far for an otherwise simple hobby though.
Absolutely 100% correct. This is also part of the reason why I need a damping system but just works sort of no matter what. If it is as simple as just strapping the flight controller to the top plate with all the weight on it, that would really be a miracle. Also, if you're able to lower your filters or just generally give the filters an easier time, they will be more capable in a wider range of applications. This would include wider temperature fluctuations. If we can turn off our filters, there would be no more tuning. Everything would just work right with a general tune because the system knows exactly what's going on with the craft
Unfortunately the GoPro stabilizer software which is just real steady doesn't work correctly with their new cameras. Gyro flow however works great and this footage has minor gyro flow applied to it. Mainly to rectify the fisheye view of the GoPro.
Hey man, great vid as always, I have one particular quad that flies amazing: it has the Kakute F7 AIO with the gyro on the foam pad connected via a ribbon cable. No gummies. I can push the D term to 60 and it's absolutely fine LOL - foam pad seems like an interesting solution, compared to all of the other tinkering. (I check in blackbox, felt really scary doing that, using RPM filtering and the filter sliders are somewhat to the right, don't remember exactly) Sadly, I don't have much time to fly nowdays (studying Uni lol), but hopefully will get back on track in the summer :D
That particular FC was super intesting. I wish we had more FC's with the gyro on a wire...a longer wire so we can mount the gyro elsewhere. The board itself would have a hard time really isolation anything because the gyro is so light it won't resist anything but very high frequency vibrations. Still was something
@@Kabab depends how you implement it. I would say zero new parts, just holes drilled and clamp's. Plus a lot more adjustability than the huge cable/clamps you tried, and a boatload less weight.
@@user-rs8zg8ey2b Yeah I agree and understand what you're saying. I may return to it if just moving the FC to the top plate doesn't show anything special.
@@Kabab I forgot to mention, Sorbothane comes in different durometers for tuning (nothing to do with the cable setup). I think the woop results were from the masses were better tuned with the dampers. Good stuff.
Hey Bob glad your still innovating & making videos!!!!! Have you ever tried a pusher style 5 inch? Oh, I think that you were just about one of the only person who will try something like this or has tried something like this I cannot remember you doing this and I watch like 98% of all your videos at least twice. I think it’s something we just have overlooked? I don’t know , but I’m highly intrigued by the concept.
Pusher crafts are very common in certain situations. They're not so generalized because of the obvious difficulty of landing and launching. They have slightly improved efficiency because there's no arm under the prop but otherwise not all that different. It's a little more difficult to balance the craft however because you need to load the weight under to get the CG closer to the prop line.
@@Kabab oh so the CG having to be inline with the the props makes it so that it’s not as simple as just flipping a frame and mounting the components on the top. I’d still be interested in seeing the results of a freestyle 5 inch pusher. Obviously you would have to be the one to build something like this with your knowledge and experience. I’m sure a 3-D printer could help with the solution of landing. Actually there’s probably a much simpler solution . We have to think outside of the current box we live in. It’s just a thought. I figured I’d throw it out there because I’ve never seen one. Imagine if it was absolutely amazing. I just wonder because 5 inch has so much better of a disk loading. I would also think that the prop wash would be better. Anyway, if you ever do it, I’ll be excitedly watching!! As I said, I figured you would be the best person in the world to bring this to.
@@fpvraver the CG doesn't need to be there, it's just best for it to be around the prop line for best performance. Some prefer it a little above or a little below. Weight distribution and CG location are very important measures that impact flight performance
What about trying something like double stacked 2.5mm arms with a 1mm foam or rubber honeycombed between them? I'm sure you've probably tried this already tho
Yeah many have tried that. They actually make a carbon product like that. It's not that useful for this purpose but it is useful in getting a really light structure. Not really good widespread use in our industry
Bob, I wonder if the battery pad is giving some significant damping. If I were designing a frame, I'd try to leverage the damping effect of the battery pad which is naturally already isolating a majority of the mass of the craft. I would also mount the flight controller to the top plate.
The pad is likely making things worse. It's a thin physical material with rebound. It'll increase amplitudes more than deaden them most likely. It'll improve a small sunset if frequencies but make others worse as thin rubber solids usually do
@@Kabab Hmmm.... I always think about that the wrong way! I guess that makes sense. /-: I wonder why the FC gummies seem to work sufficiently? Maybe b/c the FC has such less mass.
hii, you may try the rubber thingy that comes with noctua pc fans instead off screws to fix the plates to the dampeners maybe it improbes the system as there is no solid cmponent between the damper and the plate, hope it helps
Actually looks pretty nice. Impressive weight with all that complexity. The simulations are definitely helping him get that weight down. Hard to tell durability but I'm sure it's pretty good. Maybe if the mount FC to top plate thing works out, it would be really synergistic with this design. It's still unfortunately 120g
@KababFPV I like the way Chris thinks, right or wrong. It's driving forward the issue around vibrations. And with the new Betaflight 4.4 were making great steps towards a refined build. Great work 👏 👍
How do you cut your frames? Do you cut them or do you have them cut and then sent to you? How much time on average do your spend on one these frame iterations before you cut the next design? I love cable idea btw
It's extremely fast drawing designs on SketchUp. I'll usually draw an idea and think about it over a few days while I adjust the design. I'll maybe go back and forth for 2-10 days until I feel like I have something worth testing. I work with four different manufacturers and I'll cycle through them with samples generally. Sometimes I'll use cncmadness.
you ever think about using unidirectional carbon in the arms at least a couple layers and or adding kevlar since it has a way different damping effect? a single layer of kevlar would probably make a huge difference but i think uni carbon would make a better difference
Physics applied, torque and pull of each motors on the frame and static momentum created by the weight of all the stuff attached to the frame ( the sum of all forces involved must be zero ) the center of gravity of the drone must on equal distance to each motor, may be of help use soft springs for vibration dampening.
It's a bit complicated but also not. They're in place of a skewed stator. They're intesting.....but not so useful for many motor sizes. They happen to work very well on the 25mm motor
What about gyro based cardle? This approach sounds more reasonable and weight saving than trying to go crazy with the whole frame. It's just a thought, I'm not a frame designer
I wonder if the composition of the carbon fiber may play a role in the inconsistency you are see? I know a metal frame doesn't have the cache that CF has, but the uniformity of its parts might make a difference.
It makes a very minor difference. A maximum of ~6% as I've measured across the worst quality carbon to the highest end custom made carbon by the guys from MADD. I generally use upper mid grade carbon which gives most of the benefits without the extreme cost. The variation from batch to batch is less than 1% so not a huge source of issues.
@@Kabab I find that interesting. I was involved with the production of composite aircraft fuselages about 20 years ago and strand selection and layout was an important thing.
@@jf5336 it absolutely matters but the application is also important. We're not stressing the carbon in anyway outside a crash. We don't usually build a craft to crash either, at least I don't. The vibration quality that plagues us is rather unique and only so much can be done in the material itself to help. The ~6% is only the vibrational properties and not resilience to impact or any other property.
@@Kabab I agree that, short of a PhD-level study, improving the material properties of CF isn't likely to happen, so external measures, as you are investigating, are the likely best path forward. I am impressed with your work here.
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This is my favourite content, hands down. I love experimenting and pushing things forward. Seems like all people are worried about these days is can you smash something into concrete at 100 mph, regardless of whether it flies like dog water. I have no interest in that whatsoever. Thank you for taking time to make these videos, you're obviously an incredibly busy person. 💪🏻
You're at the forefront of the hobby Bob, we all appreciate the massive amount of work you put in to advance it forward. I remember coming up with ultralight quad theories as a teenager, waiting patiently as the years ticked by and there were incremental improvements in all aspects - you can only imagine how excited I was when you began releasing your work on the Toothpick.
Thanks for making that dream a reality!
I can only second that!. We bought a dozen toothpicks for our group and they are to this day our most flown rigs.
@@BloodyJMF I'm getting close to considering an HD toothpick deal soon I hope. The components are getting really good. These dampers will definitely be involved with that one. I just wish the aio boards weren't so darn expensive these days.
@@Kabab I'm kinda lucky we bought them in packs of fourty from JHE back when. Since we never really managed to break stuff we still have them together with all the replacement arms xD
And yet only has 47k followers
@@JbVest the best 47k followers out there.
I’m a machinist for 3 lumber mills and I learned a hard lesson quickly. Rarely do you solve a problem with brute force. We had the arms that lift up the boards. Thy are cycled with air cylinders. Theses arena where made from steel tube. Thy kept breaking them. So I made some out of solid plate and now the problem moved to the cylinder mounts and started ripping them apart. So I made heat treated mounts. Then we started loosing cylinders so we went up in rod size. Then the entire frame started cracking and puking out of the concrete. The solution was making arms out of solid UHMW and we have never had a problem since. Heavy objects don’t want to move and stopping them is even harder. So dropping weight and moving to a forgiving material solved it. I have seen this trend with frames getting stiffer and stiffer. The stiffer something is the more effective it is going to transfer vibrations. Think a pre cooked vs a cooked noodle. But this is a rabbit hole that is very easy to go down when you think we need more strength and more and more. When like you said mass does not want to move so bolt the FC to the biggest mass you have and isolate it from the rest of the frame. I’m surprised dampening motor mounts have not been really developed.
In this specific case, it's not quite consistent with your findings with your application. I have tried to make arms from HDPE and a number of other materials as well as sandwiched materials and many other options just to run into low frequency wobbles and resonance which is the very worst kind of vibration for this application. I do hear you completely however and will try something else you may be intrigued to see in the future.
I’m taking a break from FPV right now but man this excited me. Innovation has kinda been stagnant lately, or at least stagnant in the departments I find interesting so this was sick!
Unfortunately a lot of that has to do with how the world has just halted for the past 3 years. At this point I wouldn't even say it's a result of COVID. I would say it's more so as a result of both of our idiotic governments. Unfortunately small businesses end general developments suffer as a result
@Kabab not to mention studies that are confirming cognitive issues are more than common after a Covid infection. Some level of brain damage comes along with every
@KababFPV true glad you said what alot was thinking
Also on a break and being gaslighted from this! Got to the point where I was burning flight controllers out once a week bc of bad gyro QA. Not sustainable
@@Kabab hey buddy, i spent a couple decades building digital models of acoustic musical instruments. i've designed micro frames like the deculture fuxxor but you know everybody wanna be famous. ..understanding waveguides, take some of your carbon and cut it into strips or use plates and measure the impulse response over distance. the reason is, very simple models of acoustic instruments focusing on only the lower partials are "often correct enough," so if you design a frame by having solid data about the impulse response of your material so you can design at least the first order responsivity of the dimensions, you can at least improve upon the most elementary criteria.
but seriously, you go about it all wrong like everyone else. if you want to minimise vibration, don't clamp it on with a steel U bolt... use dental floss. if there's no mass, there's no vibration. glue and dental floss will actually make an awesome lightweight frame and it has all the tensile strength you could want.
yeah i wish some people had spent time listening to me instead of trying to be the next instant celeb. i tell people useful stuff. like if you need to code a cepstrum from your fourier analysis, just run another fft on your mag10'ed mag bins :)
You randomly showed up on my feed. This is the first video I have seen of yours and I've actually re watched five times since. Thanks for pushing the industry forward and I am now subscribed.
We promise to floss and appreciate lower production videos as long as you keep the awesome updates coming. Love your exploration and persistent trial and error approach sir.
Amazing stuff! Length is inconsequential, don't sweat the edits. Really looking forward to more of this content.
Bob is one of those few guys who pushes the industry forward, he figures something out, then the rest of community catch him up after 1-2 years.
From my shallow experience what I found out was - for high performance 5 inchers sometimes it's better to reduce the filter (faze) delay but get some more noise, than get the absolutely clean gyro traces after filtering. PIDs should act on the gyro signal which is closest to the present time.
It's good to have frame resonance higher than 200hz, then to cut it out with either static or dynamic notch.
Sorry for my generalizations, that's related to my build.
It’s a pleasure to see you back!
I think you should call that new frame Mr. Floss ;)
Pushing the hobby forward all the time!
You rock man. We need more innovation to come back in this hobby. I loved they hayday of seeing different solutions and frame design. Keep chugging away man.
He does it again folks! Again and again and again and again! The man, the myth, the MF Legend!!! No one is like you in this hobby, especially after all these years. Cheers to you my friend. 🎉🎉
Lots of blackbox. :-) Warms my heart. Love to see the engineering at work! Mark Rober approved!
😂 I always use BB. I just don't put a whole lot of effort into dissecting it because it reminds me of my organic chemistry lab exams where we get a similar graph and need to explain which molecule we're looking at which was so annoying....also because you can go so deep into it and I'd rather focus on high level ways to get things working right without fuss. I use your presents in BF all the time. Sometimes they match right and it's better. 👍
@@Kabab yeah it is just a good tool. Don't be shy. Embrace the obsession.
My take is there are lots of frames out there that work well for vibration across all the quad classes. If we narrow to 5" class, that probably has the most: Apex, Martian II, Trans Tek Laser, Source One, etc... The gist I'm gathering is you want less weight and that is then where the vibrations creep in?
OR
I think you just have some engineer in you, because this video is like the engineering method 101: design, build, test, measure, modify, repeat. Tools like finite element analysis can shorten the cycle, but can take the fun out of it when the hobby is the method, not doing the finite analalsys in front of a PC; which then also needs real-world validate (is a part of design step).
Mark Spatz, P.E. (licensed)
(in good company here 😎)
@@uavtech I definitely prefer and enjoy the build-test approach. Moreso because I learn a lot more about other things than just what I'm trying to focus on. FEA is helpful but is a very sterilized approach which doesn't always lead to the right result. That and I'm definitely looking for a way to drop weight. 20g less with comparable or better vibration management is gold to me.
@@Kabab 100%
Enjoying your work!
@@uavtech Really is amazing how well the source one v3 performs stock and its even better if you move to 6mm arms its dead quiet in the bb. I've got some far more expensive frames that resonate all the way up to 300Hz.
Fascinating stuff indeed, Bob! Fascinating testing! 😃
But you were spot on when you mentioned that the plate with more mass vibrates less. As more mass, more energy you'd need to make it move at all.
Anyway, stay safe there with your family! 🖖😊
Very cool seeing all the testing and frames you are producing to test!
I’ve always wanted to attach the FC and camera to the battery, the least vibrating mass on the craft, and then isolate the motors, by putting hem on the other side of the battery mass. Pretty much strap the camera and FC to the battery, and then strap that to the frame/motors. Sticking it to the top plate is something I’ve always thought made sense as well. Great to see you do so much research in all these different avenues of possibilities. Thank you for sharing ythis. It’s so educational in so many dimensions. Yes! Faster videos, less production value is better if you can share our findings faster. Great video! You have one of the best presentation skills in FPV. Quick, concise, relevant, good pace, actual knowledge, etc.
I'm hoping it's really as simple as moving through FC to the top plate and we instantly all get ~20% damping right off the bat
@@Kabab I guess one can make a simple test by printing some lipo guard, sticking it on top of the battery and just duct taping the FC to it. Not production ready solution of course, but should be enough to estimate if this particular spot gives better results.
So glad you are testing things out and sharing in video with us here. SO AWESOME!!!
Thanks k you for the work you do. Please take the time to upload your findings to RUclips, I think it is really beneficial for all the flyers who see you videos and are also experimenting themselves
That’s great food for though. Year after year you’re pushing stuff and concepts forward. You deserve huge thanks for that ❤
mounting the fc near the main mass of the quad seems such a good idea, mass is a crucial element in vibrations absorption so we should indeed play with it
Cool video, a lot of really interesting concepts in there. From my experience and simulations I can't really find a way forward with rubber damping parts except for lightweight components with gyros that need vibration isolation for higher frequencies. If you try to soft mount heavy parts (like go pro or battery) you have two heavy bodies that can move relative to each other with low resonant frequency... Catastrophe!
Anything like rubber that is springy as well as damping will create new resonances as well as soaking up energy. The heavier the sprung mass and the softer the rubber the lower the new resonance and the bigger the problem it causes. Soft ruber is good for absorbing vibrations but also causes lower frequency vibes.
If we want to "soft mount" heavy parts like Go Pro or Battery we need to use very stiff ruber to avoid creating low frequency resonance. Unfortunately stiff rubber doesn't really absorb vibration!
Damping grease has zero spring so doesn't create a new resonance which is why it consistently works. Looking forward to seeing what comes next, keep at it.
i made my own camera mount which mechanically decouple the camera. simple as that. no jello. no ND nonsense. no shaking. perfect footage on EVERY quad with every different action cam. DJI, insta36 or gopro. from 3" all the way up to 6" works. i am trying to convince people for 2 years to try my mount for free. most refuse and say i need change PIDs. or must use ND filters. or other BS. at this point i gave up. my footage is perfect. always. while others still struggle. happy to see you also working on that.
I don't use an ND for vibrations. I use it for the actual ND effect to get motion blur
@@Kabab which i can totally appreciate as cinematic pilot. and thats the ONLY way NDs should be used for. but lets be honest 90% say it helps with jello which is right but only like 50% and its a patch for an entirely different problem. anyway as i said i am happy to see others trying to deal with the actual vibration problem instead of just use other tools to cover it. good job
Thank you for sharing this meticulous yet open ended insight 🙏🏻
Welcome back
It seems that you should try those new low-noise helical props. Since they reduce air turbulence (and vibration) making them more efficient and quieter.
I literally put a video up on that this morning. All those claims are false by MIT unfortunately but the overall prop design that was made may not be a total waste. See the video I put up this morning
@@Kabab Oh okay. Thanks.
@@Kabab I watched it. That kind of propeller design is a whole new area to experiment with and make videos.
About frames:
Have you looked into making frames with a biomimicry structural design? They are of course difficult to design and produce, but I think that method would solve your vibration issues, as well as make them lighter. Another drawback is that you'd have to add plastic skins over them to reduce drag.
(I looked through most of your video thumbnails, and I didn't see any.)
Glad to see new content from you. I really enjoy your videos, the new ideas, the successes, the failures. I floss more often too :D
I’m simply interested in what ideas you are playing around with. A basic one take vlog style with you and the prototypes , cad, etc and little to no editing would do it for me.
That's where I'm heading it's just that from CAD to frame to fly is like, weeks in between....still gonna give it a shot with the next one
My motorcycle handle bar uses an internal brass rod with o-rings to dampen instead of a heavy weight at the bar end.i wonder if a similar concept would work next to each motor
I've got a story of similar concept coming up. Instead of weight it uses tension.... Looking quite good
I have no clue what most of the things you’re talking about but I’m just getting into FPV drones and I’ve been binge watching your videos 🫡
Yeah this video is a little more advanced but you'll understand it after you build maybe your third quad. It'll all become obvious
Very interesting I can't wait to see the results and graphs on the next video.
I reduce the vibrations in a slightly different way. I modified the betaflight configurator so that I can see the unfiltered vibrations on the motor as it spins from the configurator. The quadcopter is anchored not very hard, but enough not to fly away on soft material. I rotate the motor to a certain speed, record the maximum vibration amplitude and stop the motor. After that, I add a little adhesive tape to the propeller and act according to the method for worse or better. Thus, it turns out to reduce vibrations several times even on new motors and propellants. On my old gopro 3, this reduces the effect of jelly to almost zero.
Jello isn't the issue here. It's the vibrations getting to the gyro. What you do is dynamic balancing and the best way however it's very time consuming and doesn't last once you damage a blade a little or swap blades or even just unscrew and tighten a blade.
@@Kabab I tried today to change the flight controller to the top plate for the sake of interest. Without rubber dampers on the top plate but with dampers on the flight controller. According to the logs - it got a little worse. So apparently there is no difference in person closer or farther from the battery.
@@ekap123321 definitely good input. Thanks for testing.
You just reminded me to floss, I skipped that this morning, good content Bob!
Amazing presentation. Can’t wait to see this project grow.
An old engineer told me; ‘to remove all vibration, one must remove all mass… however this is physically impossible.’
The King is back. Thx for all the research and testing.. Very curious what the results will be in the end.
Someone really gets engineering when they say, "...generate heat from vibrations." Armed with engineering knowledge and experience, you open up solutions that are fantastically innovative, like braided wire for dampening, and in my field, eccentrically-braced frames which bend steel beams to generate heat during an earthquake. Like brakes on a car to dissipate energy, it's all about energy transfer and ultimately intentional heat generation. Friction, elastomeric materials, plastic deformation of ductile materials, even fluid turbulence all do the same thing at the end of the day.
Great research, looking forward where it will get you to
Interesting! I had tons of oscillations in my last kwad to the point where I now sell it. Would be great to see an overall performance improvement. Keep up the good work!
Some damping grease may help that craft from an early death.
@@Kabab I guess I should try 🤔
Excellent video my man!
The smoothest quad I’ve ever flown to date has been my current catalyst machine works BangGod. Tbh I’ve flown many different quads and if they all have the same motors and props and 6s power, they all fly so similar once tuned correctly. I stick with the banggod because it’s the first quad I’ve had that is damn near indestructible.
10:48 oooooh pretty! Yeah, that’s fantastic for anything running filters - it’ll decompose really easily under an FFT transform!
That's my expectation
Just starting to watch, Bob, but I just wanted to say... This is the way.
Great exploration! Thank you for your time!
Bro is simultaneously an engineer and a doctor. Nuts.
How does adding a crossbar compare to doubling the arms in terms of vibration reduction/weight? Would be interesting to see this comparison on h-frame with sidebars and an x-frame with front and rear bars
It helps on frames that need the help. It sometimes makes things worse on frames that don't need it. So it's consistently inconsistent 😑
how you played with SpeedyBee Master 5 HD Frame. The whole FC is mounted on TPU section in the middle of the body.
BTW. I been experimenting for last 2 years with same issue you are describing.
You will find that carbon tubes as arms cut down on vibrations significantly. Maybe combining speedybee concept with CF tubes would give us interesting results,
The speedybee system is not much better than the rubber grommets already built into the FC. It may help a bit more. Probably doesn't hurt since the stack is generally low weight and hard to oscillate. I may pick one up to see how it is
Thanks for sharing Bob.
In honour of your latest design, I'm going to take out my old BlackOut Mini-H quad for a fly :)
The single greatest contribution to the industry imo. Black out mini H. Just so ubiquitous with the early industry and classic.
@@Kabab Reckon you are doing your fair share to make a big difference too.
Not to mention improving FPV pilots orsl hygiene 😬
I hope BlackOut reads this encouraging message.
Nice video, i loved all the data and perfect explanation. Im not into drones but i followed along easily
Inspiring video! How about designing a frame which would have a room/compartment in the centre to mount the battery? The FC would be installed in its own carbon cage (to protect it from crashes), which would be fixed directly to the battery, independently of the battery-frame mounting. This way there would be a physical isolation of the FC from the frame with the battery (being the heaviest component of the quad) acting as the vibration absorber, separating/isolating the motors/frame from the FC..
That would be really nice but we're working with a weight restriction here. It costs a lot in weight to make different components inside. Especially for the battery. It's also very difficult because no battery is the same size and they change size over their lifespan too
wow love the thorough testing you do.
When you said the idea was basically to have the flight controller closest to the main mass of the quad so you mount it on the top plate - what if we just mount the battery on the bottom plate? maybe having the center of mass so high above the prop line is causing these vibration issues?
The problem with moving the batt to the bottom is that the quad then flies different. This is how race quads mount their batt because they crash often and batt on top is destroyed in most crashes. Weight distribution is one of the most significant factors in a quads performance
100% Silicone calk/sealant sandwiched between frame components does wonders to reduce the noise floor. Because it's a mild adhesive, it seems to really unify the frame pieces. It's better than greasing it because it sets up and doesn't constantly ooze out and attract dirt.
Yeah that's an option but it suffers from the same issue as anything else between carbon. You bolt it together to try and keep it strong which negates anything between mostly
babe wake up kabab uploaded
In long range shooting, people tune their barrels to reduce vibration by having a mass near the end of the barrel that they can adjust the position of. Maybe having a small and movable weight on each arms can help reduce vibrations when you adjust their positions?
That's a very very interesting idea but it would directly impact flight performance too. I actually do believe it would work however. I just never thought about it.
You have no idea how good my day became just for getting a video notification.
I'm glad the FPV community has Bob and Joshua
very interesting video! good to see someone using the data to innovate
Helll yea brotha hope all is well miss ya man great info as always !!! Mandalooooo to the mooonnn
The whole idea is to decouple the vibration from the motors. The more material the vibrations need to travel through, the more damping you will see, hence why moving the FC to the top plate has more of an effect because the vibes have essentially more distance to cover before reaching the FC. Think of all the mounting points and the material between them as conduits for conducting vibrations. The further your mounts are away from the source of the vibes, the more of a damping effect you will see. Configure the build like a maze where the vibes have the longest path to travel before reaching the FC.
That's what I'm hoping is happening...we'll see
This is also what I discovered while prototyping, interested in the results between the different position on the H frame because of the shorter arms
That's where the H frame theoretically makes sense. However I think you'll loose a lot of stiffness and overall rigidity in the whole structure that it creates new problems like lower freq vibrations and more critical resonance modes. So trying to balance that trade-off, you kind of end up with the standard X frame. Just my assumption. We'll see how your test works out
@@ariafpv It's less about X or H shape and more about the interfaces between parts IMO. I'd first focus on building a rigid structure for the arms and motors to have a solid foundation. From there you work backwards and come up with a clever way to decouple that from whatever part your FC is mounted to. The FC mount doesn't need to be strong in itself, it just needs to hold in it's place.
@@KevPV yes kind of what I meant. With X style I was just refering to a standard layout creating a rigid core in the center (opposed to the H frame he showed). Doesn't need to be the usual 4 interlocking arms. As you said the goal is to only have the FC be "decoupled" from the rest
Food for thought for you. The greater surface area that dampening material is able act with the more effective it will be. I suggest three or four milimeter neoprene foam.
Yeah that's why I'm considering doubling up on dampers just to test but I could never run with that because of the added weight.
Curious if you’ve tried KISS before. They recommend hard mounting for best experience and was wondering what your thoughts on flying it are. Thanks for all the good research you do!
I don't have a lot of experience with kiss but a direct hard mount is better sometimes. The rubber grommets have a lot of bound to them and can be excited by some vibrations leading to much worse vibrations. Not usually however since the FC is usually very low weight. The frequency is usually very high and not approached by most crafts.
Good to see innovation, good luck! In your experience, do side braces help with arm torsional vibrations? In other words, can a box frame be better than X?
Good to see you back with a video. Great stuff.
What about mounting the gyro outside of the flight controller, on its own soft mount
Right that is something I've requested from manufacturers on and off. I think it could possibly open up to more options but really what we need are a few gyros mounted to different areas on the craft. Then code that will sample all of them to get tht best data. Or, just deal with the vibration peaks really. The general noise floor just needs to go down a bit.
Really interesting ideas. Keep them coming 👍
Cool stuff!
What if you took some of the rubber damper things and mount them on the arms, just like on the bottom or top but not sandwiched with anything 😮
Have you tried putting a ballast or weight like square brass with 30x30 holes on top of the flight controller stack with those dampers to change the frequency of the vibrations?
That would work great but you're also just adding gdead weight which is not great.
Compound bows have lots of wierd stuff to reduce vibrations. Sometimes the stabilizers have a weight on the end with a very soft rubber between the weight and the rest of the stabilizer. So now I'm wondering if a rubber tail with a small weight on the tip would do anything on a quad..
yeah I've looked at that. It's like a damping mass on a stalk to manage low frequency wobbles. Unfortunately that's going to impact flight performance a LOT more than it could ever be worth
Are you accounting for the fact that the weight of the batter and rubber dampers due to momentum? Like wiggling a ruler or a fat guy on a diving board? And what about the weight or even the maneuvering patterns in correlation to the frame style?
I think you're talking about new resonance from the mounts allowing for wobbles. That's the reason I made the stance as wide as I could but it still happened. I'm not sure what you're referring to regarding maneuverability
I know nothing about this lol but could you use the bushings from longboards? I’ve found they have great durability and dampen vibrations quite a bit
Interesting
Lets say instead of suspending the fuselage section on the arm section with cables we just have a soft material in-between, it can be whatever tpu, rubber, polyurethane try a set of different stiffnesses. this could be attempted on a lot of different frames by just sticking a battery pad between the arm section and the middle plate. It's similar to chris rossers dampening grease idea but less messy.
yeah that works except that you also bolt the thing together which negates anything put between the carbon. We need the actual material that's damping to also be durable enough to hold the craft together.
Vibration isolation and vibration damping are two separate items. I would consider the rubber devices you have there as isolators. They may provide some damping, but their primary purpose is to provide isolation between the two ends of the isolator. It is also important to consider the frequency range of the isolator and how the mass and stiffness of the structure interact with the isolator. I think this is great and we are only scratching the surface here!
We've been clawing at the surface for over a decade now. There's no surefire way to get any sort of hardware damping consistently. Vibration isolators don't work for anything above 3" it seems. I'm guessing the amplitudes are too high when the prop size gets bigger.
@@Kabab I agree, this problem is not easy. I would like to see more of a focus on the frequencies that mater to the FC and what it’s just ignoring. From my understanding, we want to focus on the low frequency flight maneuvers and prop wash frequencies. When the vibration gets to the FC(gyro) it should be cleaned up from motor noise, frame resonances, etc. Most isolators aren’t going to do that well, the simple rubber ones are going to isolate at higher frequencies and maybe not in the correct axis, and if they do isolate at the proper frequencies they are likely to remove the important information as well. Setting up an isolator test stand might be something to consider.. set your quad on the bench and have a beat up prop and slowly ramp up the RPM and record BB… Try it hard mounted and then with the isolators… try to get enough data for a transmissibility curve… but just trying whatever isolator is available off of Amazon makes it tough. Should we be looking at the other end of the problem maybe? Engine isolation? Certainly the approach for cars and real airplanes…
@@REDhlg There is one way we could do this that could work out best. Two gyros. One hard mounted, one soft. Subtract anything that changes from the hard mount to the soft mount. Everything that's the same overall amplitude and movement is real movement that the FC needs to know about. Everything else is garbage.
In precision shooting competition, barrel harmonics is a big issue and there are several ways to deal with them. The simplest is using a heavy barrel (just like thicker drone arms), this only moves harmonics to a higher frequency, you still have to tune your handloads to match the barrel or use a barrel tuner (movable weight).
Another way to bypass harmonics is to have the muzzle of the barrel be constrained, this usualy means clamping the tip of the barrel to the stock, in drone terms this is like having a large structure of thinner struts instead of thicker one peice arms.
Now to realy remove harmonics, deaden the barrel, you have to convert the energy, there are a few ways to do this. The simplest is to remove direct load paths, this means barrels with dimples, outside threading and axial holes arround the barrel, in drone terms this would mean the arms would have holes and zigzag edges in so that the forces have to go around corners (aka stress risers).
The other way is dissimilar materials, this is like an aluminium or carbon fibre barrel with a stainless steel core, since the materials have different stiffness, much energy is lost transfering the vibrations. This is why carbon fibre is inherently a good damper since it is a matrix of epoxy resin and carbon filament, this is also how cars remove body vibrations by bonding a layer of urethane to the metal pannels.
@@paint4pain of these options, the different materials could be the best one for us except that in our case, we don't see waves of vibrations as much as we do overall twisting or wiggling of components. Waves are approachable with different materials and we still get some of that but the main issue is the odd twists and wiggles.
One of the main benefits of the H frame design which attracted me to it is that the frame will essentially have no pitch action vibration wise because there's nothing to wiggle. At least not with the energy given. Yaw won't be a big deal and is seldom a problem, roll is the only issue I need to resolve. The body twisting. That's the only notable mode that's gonna kill it. I have some tricks I'm gonna try....... we'll see
I use Kyosho Zeal for all of my quads flight controllers, Spektrum AS3X receivers, and helicopter gyro mounting with no hardware, it's the cleanest and best solution that I've found to this date for minimizing vibrations.
Something like that is always helpful but the FC is so low inertia it can only resist higher frequencies
A great video, and well worth watching. You have a new subscriber, keep up the good work! :)
I came back looking for a link for the hardware mentioned in the video. But I don't see one.
What specific hardware are you looking for? If there is any it'll be on fpvcycle.com. The frames are just test samples so none of that is anywhere. The most useful item right now that's in stock would be the 23mm short motors which pretty much transform any 3" ducted cinewhoop into an amazing flying craft compared to what it was previously if it has any motor size narrower than 22mm wide.
It would be interesting to see the effects of two pusher propellers and motors (motors and propellers below arm)in various configurations with two standard propellers and motors (motors and props above arm). Two pushers directly across from each other in position 1 & 2 or two in position 1 & 3, or 2 & 4. Maybe I'm just crazy.
I'm wandering in here with no background in DIY drones so I have no idea if this is viable to adapt but it seems worth mentioning
I saw a vid on silencing a buzzy take-down bow. The main thing they did was add some adhesive pieces of thin felt on the ends of the limbs and in between where the limbs attach to the handle
Right. Would love to slip something between carbon plates but it doesn't really work out since we always tighten the screws anyway
Hi Bob, WoW! I have missed your videos,
Kabab what about a soft mount like the naked bmpcc for the fc and motors then .
Yeah that's an option too but the material is difficult to settle on because anything that's physical will have rebound to it which will often make it worse. It's also difficult to consistently apply
This makes me want to go to a park and fly through the wooded area ❤
Chris Rosser is the man when it comes to frame resonance
..😉
Sure, resonance. What about the rest of the vibrations?
@@Kabab yeah that too, i forgot to mention. You probably know him already. He's based here in the UK. Got his own frame range, and goes in pretty hard scientifically. And no I'm not biased as i don't own any of his frames. Just saying incase you haven't heard of him. 😉
@@k1ortia yes I know of Chris. His work is good however he tends to negate the real world often and believes he can simulate everything. He also seems to think he knows everything there is to know so it's pretty difficult to work with him. A problem which I too have had issues with in the past but life has kicked me in the butt enough to let go of all that. Maybe in time he'll come around too.
@@Kabab Funny you should say that, as iv often thought the same to. It's as iv everything is purely simulation based as apposed to real life testing. I'm glad you've put some new content out though as iv not seen anything for a while, so i shall be watching and continue to watch the future videos..😊
@KababFPV , did You try to talk to some car guys companies that make various PU hardness bushings in car suspensions? maybe they could make various hardness mounts with inserts like M3 or even make a two step proccess and use two different PU`s in one mount ? then it would be possible to to make cone like mount poured over with second PU, all enclosed in small cylinder like shape... ofcourse, much much softer PU`s than to the car bushings...
Yeah I would but I don't know what hardness and I'm not confident the same one will work for everyone or even different air temperatures. That's why I need it to work already before I go ahead and try and improve it
@@Kabab but then, You already use softmounts that have no rating at all and from my experience, those black mounts are lottery since those are mainly made from recycled PU ( so the production facility uses whatever available and then add some black pigment to unify the look), so You`re already in the lottery business ;) take a look at car poly bushings or skateboard poly bushings, these are made with color different shore hardness grade. maybe 3 grades (soft/med/hard) would stadarize the softness/hardness...
@@blazefpv3038 for now, they're only proving useful for the smaller 3" prop size and on a cinewhoop. I doubt even the right hardness would make much impact on the 5". I wasn't seeing any improvement at all. It was actually much worse. Hard standoffs were drastically better. But I'll keep testing things. I might double up the mounts just to see how it goes. If that works then a harder material will work.
I had to print some plastic washers for my motor screws once they were abit to long and the quad ran great after im pretty sure the bolts are like tuning forks if you use plastic washers on the bottom and a rubber gasket between the motor and frame im sure it would isolate alot of vibration at the source
At the beginning of the video I show the soft motor mounts we used to use. They sort of worked sometimes but also made things worse other times. Ultimately nobody can tolerate them anymore because your motor screws come loose and it's awful overall to deal with.
I'd love to try this frame out...
be fun to tinker with.
how does it take a hit?
I'll find out. Because the H frame arm is so much shorter, I kinda think it won't be much less durable
Soft copper tubes absord resonance very well.
For sure. Copper is light too.
After years of carefully tuning to get rid of vibration and then constantly failing, I came to the realization that most of my vibrations come down to temperature. Not only do the resonance frequencies of the materials (carbon/rubber/gel) change, but also the characteristics of the electronics. Most FC use simple RC oscillators which aren't temperature stable, so they drift. So tuning filters for specific frequencies is completely pointless when you are flying in a wide temperature range. Not only that, if you look at datasheets of carefully profiled Gyros you'll find parameters like "Sensitivity percantage change per Kelvin", "Sensitivity percentage change per Volt" (at specific temperature), "Zero-rate offset over temperature change" and "Zero-rate offset drift per Volt" (at specific temperature). So in my opinion testing of frame vibrations only makes sense if you perfectly temperature control at least the electronics. A common practice to achieve that is to encapsulate the electronics and heat them to a fixed temperature. I don't think anyone would go that far for an otherwise simple hobby though.
Absolutely 100% correct. This is also part of the reason why I need a damping system but just works sort of no matter what. If it is as simple as just strapping the flight controller to the top plate with all the weight on it, that would really be a miracle. Also, if you're able to lower your filters or just generally give the filters an easier time, they will be more capable in a wider range of applications. This would include wider temperature fluctuations. If we can turn off our filters, there would be no more tuning. Everything would just work right with a general tune because the system knows exactly what's going on with the craft
Wow !! hard work there Bob !! so what is the conclusion ? also that super stabilized footage is RAW ? or the GoPro stabilizer algorithm ?
Unfortunately the GoPro stabilizer software which is just real steady doesn't work correctly with their new cameras. Gyro flow however works great and this footage has minor gyro flow applied to it. Mainly to rectify the fisheye view of the GoPro.
Hey man, great vid as always, I have one particular quad that flies amazing: it has the Kakute F7 AIO with the gyro on the foam pad connected via a ribbon cable. No gummies. I can push the D term to 60 and it's absolutely fine LOL - foam pad seems like an interesting solution, compared to all of the other tinkering.
(I check in blackbox, felt really scary doing that, using RPM filtering and the filter sliders are somewhat to the right, don't remember exactly)
Sadly, I don't have much time to fly nowdays (studying Uni lol), but hopefully will get back on track in the summer :D
That particular FC was super intesting. I wish we had more FC's with the gyro on a wire...a longer wire so we can mount the gyro elsewhere. The board itself would have a hard time really isolation anything because the gyro is so light it won't resist anything but very high frequency vibrations. Still was something
Try the steal cables bent in a paperclip shape (oval with flat sides), in X and Y direction.
What motors are those at the end? Link
It's just cumbersome to deal with the wire in such small segments. Way too much work
@@Kabab depends how you implement it. I would say zero new parts, just holes drilled and clamp's.
Plus a lot more adjustability than the huge cable/clamps you tried, and a boatload less weight.
@@user-rs8zg8ey2b Yeah I agree and understand what you're saying. I may return to it if just moving the FC to the top plate doesn't show anything special.
@@Kabab I forgot to mention, Sorbothane comes in different durometers for tuning (nothing to do with the cable setup).
I think the woop results were from the masses were better tuned with the dampers. Good stuff.
Hey Bob glad your still innovating & making videos!!!!!
Have you ever tried a pusher style 5 inch?
Oh, I think that you were just about one of the only person who will try something like this or has tried something like this I cannot remember you doing this and I watch like 98% of all your videos at least twice. I think it’s something we just have overlooked? I don’t know , but I’m highly intrigued by the concept.
Pusher crafts are very common in certain situations. They're not so generalized because of the obvious difficulty of landing and launching. They have slightly improved efficiency because there's no arm under the prop but otherwise not all that different. It's a little more difficult to balance the craft however because you need to load the weight under to get the CG closer to the prop line.
@@Kabab oh so the CG having to be inline with the the props makes it so that it’s not as simple as just flipping a frame and mounting the components on the top.
I’d still be interested in seeing the results of a freestyle 5 inch pusher. Obviously you would have to be the one to build something like this with your knowledge and experience. I’m sure a 3-D printer could help with the solution of landing. Actually there’s probably a much simpler solution . We have to think outside of the current box we live in.
It’s just a thought. I figured I’d throw it out there because I’ve never seen one. Imagine if it was absolutely amazing. I just wonder because 5 inch has so much better of a disk loading. I would also think that the prop wash would be better. Anyway, if you ever do it, I’ll be excitedly watching!!
As I said, I figured you would be the best person in the world to bring this to.
@@fpvraver the CG doesn't need to be there, it's just best for it to be around the prop line for best performance. Some prefer it a little above or a little below. Weight distribution and CG location are very important measures that impact flight performance
oh staggered magnets
but the stator isn't twisted, too
and what do you think about rubber sheets instead of grease?
Right. Instead of a stator skew, the magnets are staggered
What about trying something like double stacked 2.5mm arms with a 1mm foam or rubber honeycombed between them? I'm sure you've probably tried this already tho
Yeah many have tried that. They actually make a carbon product like that. It's not that useful for this purpose but it is useful in getting a really light structure. Not really good widespread use in our industry
Bob, I wonder if the battery pad is giving some significant damping. If I were designing a frame, I'd try to leverage the damping effect of the battery pad which is naturally already isolating a majority of the mass of the craft. I would also mount the flight controller to the top plate.
The pad is likely making things worse. It's a thin physical material with rebound. It'll increase amplitudes more than deaden them most likely. It'll improve a small sunset if frequencies but make others worse as thin rubber solids usually do
@@Kabab Hmmm.... I always think about that the wrong way! I guess that makes sense. /-: I wonder why the FC gummies seem to work sufficiently? Maybe b/c the FC has such less mass.
@@WEEBER13 it's not intuitive at all. I only know this because I've tested and seen first hand.
hii, you may try the rubber thingy that comes with noctua pc fans instead off screws to fix the plates to the dampeners maybe it improbes the system as there is no solid cmponent between the damper and the plate, hope it helps
Those are just soft rubber. Not all that different from the vibration mounts I'm using
@@Kabab you're right I meant to replace the metal screws that fix the vibration mounts to the carbón with those
@@alejoush If it was a cinawhoop that wouldn't likely be taking hard crashes just use nylon bolts instead of steel.
How you feel about the AOS HD03 frame?
Actually looks pretty nice. Impressive weight with all that complexity. The simulations are definitely helping him get that weight down. Hard to tell durability but I'm sure it's pretty good. Maybe if the mount FC to top plate thing works out, it would be really synergistic with this design. It's still unfortunately 120g
@KababFPV I like the way Chris thinks, right or wrong. It's driving forward the issue around vibrations. And with the new Betaflight 4.4 were making great steps towards a refined build.
Great work 👏 👍
How do you cut your frames? Do you cut them or do you have them cut and then sent to you? How much time on average do your spend on one these frame iterations before you cut the next design? I love cable idea btw
It's extremely fast drawing designs on SketchUp. I'll usually draw an idea and think about it over a few days while I adjust the design. I'll maybe go back and forth for 2-10 days until I feel like I have something worth testing. I work with four different manufacturers and I'll cycle through them with samples generally. Sometimes I'll use cncmadness.
you ever think about using unidirectional carbon in the arms at least a couple layers and or adding kevlar since it has a way different damping effect? a single layer of kevlar would probably make a huge difference but i think uni carbon would make a better difference
Yeah tried that. Doesn't do anything at all. Unidirectional is also super weak and splits apart very easily. Experimented a lot with it.
I've always thought there could be micro balancing and micro angle of attack issues of motors that causes oscillation...
Physics applied, torque and pull of each motors on the frame and static momentum created by the weight of all the stuff attached to the frame ( the sum of all forces involved must be zero ) the center of gravity of the drone must on equal distance to each motor, may be of help use soft springs for vibration dampening.
What's up with the offset magnets, seems like that could reduce desyncs.
It's a bit complicated but also not. They're in place of a skewed stator. They're intesting.....but not so useful for many motor sizes. They happen to work very well on the 25mm motor
What about gyro based cardle? This approach sounds more reasonable and weight saving than trying to go crazy with the whole frame.
It's just a thought, I'm not a frame designer
sure that would be great but still a challenge a design and actually have it work.
I wonder if the composition of the carbon fiber may play a role in the inconsistency you are see? I know a metal frame doesn't have the cache that CF has, but the uniformity of its parts might make a difference.
It makes a very minor difference. A maximum of ~6% as I've measured across the worst quality carbon to the highest end custom made carbon by the guys from MADD. I generally use upper mid grade carbon which gives most of the benefits without the extreme cost. The variation from batch to batch is less than 1% so not a huge source of issues.
@@Kabab I find that interesting. I was involved with the production of composite aircraft fuselages about 20 years ago and strand selection and layout was an important thing.
@@jf5336 it absolutely matters but the application is also important. We're not stressing the carbon in anyway outside a crash. We don't usually build a craft to crash either, at least I don't. The vibration quality that plagues us is rather unique and only so much can be done in the material itself to help. The ~6% is only the vibrational properties and not resilience to impact or any other property.
@@Kabab I agree that, short of a PhD-level study, improving the material properties of CF isn't likely to happen, so external measures, as you are investigating, are the likely best path forward. I am impressed with your work here.