I put some steel cable on a quad...

Table of Contents:
00:00 - Intro
06:00 - The part about the steel cable but probably watch the whole video because that's not the really interesting part.
The best toothpaste on the market (no joke):
fpvcycle.com/products/spry-to...
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[@OutaTimeFPV]

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!

[@Kabab]

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

[@christopherleveck6835]

​@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

[@saittafpv5846]

​@KababFPV true glad you said what alot was thinking

[@acaseofcorona]

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

[@atomictraveller]

@@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 :)

[@flightevolution8132]

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 can only second that!. We bought a dozen toothpicks for our group and they are to this day our most flown rigs.

[@Kabab]

​@@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.

[@BloodyJMF]

@@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

[@JbVest]

And yet only has 47k followers

[@Kabab]

@@JbVest the best 47k followers out there.

[@willpowerfpv3246]

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. 💪🏻

[@trpalmer]

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.

[@fpv_am]

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.

[@anthonygrec0]

Amazing stuff! Length is inconsequential, don't sweat the edits. Really looking forward to more of this content.

[@uavtech]

Lots of blackbox. :-) Warms my heart. Love to see the engineering at work! Mark Rober approved!

[@Kabab]

😂 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. 👍

[@uavtech]

@@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 😎)

[@Kabab]

​@@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]

​@@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.

[@Atlas_FPV]

Pushing the hobby forward all the time!

[@ChrisParayno]

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.

[@MCsCreations]

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! 🖖😊

[@leahcim501]

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. 🎉🎉

[@MADmidway]

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.

[@ChrisRosser]

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.

[@fpvgiggles]

Very cool seeing all the testing and frames you are producing to test!

[@nikotttin]

It’s a pleasure to see you back! I think you should call that new frame Mr. Floss ;)

[@Ledroneclub]

That’s great food for though. Year after year you’re pushing stuff and concepts forward. You deserve huge thanks for that ❤

[@blackmennewstyle]

Welcome back

[@T-kind]

So glad you are testing things out and sharing in video with us here. SO AWESOME!!!

[@VinM817]

Amazing presentation. Can’t wait to see this project grow.

[@timair_fpv]

Thank you for sharing this meticulous yet open ended insight 🙏🏻

[@brianevans4]

Thanks k you for the work you do. Please take the time to upload your findings to KZbin, I think it is really beneficial for all the flyers who see you videos and are also experimenting themselves

[@kydawg1684]

Good to see you back with a video. Great stuff.

[@MrFadjule]

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

[@samuelfpv6603]

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

[@justainchoe6141]

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'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

[@dmitry.murashenkov]

@@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.

[@uneekpcs]

Very interesting I can't wait to see the results and graphs on the next video.

[@LeshaRodin]

Great research, looking forward where it will get you to

[@seewell8168]

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.

[@Kabab]

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

[@controlflow89]

Great exploration! Thank you for your time!

[@jayqfpv6835]

The King is back. Thx for all the research and testing.. Very curious what the results will be in the end.

[@MystikSquash]

Awesome work ninja. Thank you for sharing

[@Will_FPV]

Really interesting ideas. Keep them coming 👍

[@memefpv]

very interesting video! good to see someone using the data to innovate

[@HolaACchillin]

Interesting video! Can’t wait for the next one!

[@FordMustangGTRocks]

Nice video, i loved all the data and perfect explanation. Im not into drones but i followed along easily

[@califpv]

Great video man

[@owensspace]

Wow, subscribed. This is such a helpful video

[@WKfpv]

You have no idea how good my day became just for getting a video notification.

[@kiddfpv]

Keep us updated!

[@sandersassen]

You just reminded me to floss, I skipped that this morning, good content Bob!

[@ndcapper]

Interesting stuff Kabab

[@friendlynomad9840]

I'm glad the FPV community has Bob and Joshua

[@cloudpandarism2627]

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]

I don't use an ND for vibrations. I use it for the actual ND effect to get motion blur

[@cloudpandarism2627]

@@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

[@FlyZoneFpv]

Good stuff bud👊🏻

[@freesk8]

Keep up the good work! :)

[@letmetwistyourmind]

A great video, and well worth watching. You have a new subscriber, keep up the good work! :)

[@JAYFPV24]

Helll yea brotha hope all is well miss ya man great info as always !!! Mandalooooo to the mooonnn

[@CaseyGray58]

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.

[@jtcustomknives]

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.

[@Kabab]

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.

[@acaseofcorona]

Love this man

[@angleofattack5942]

Bro is simultaneously an engineer and a doctor. Nuts.

[@drdrhelmut]

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!

[@Kabab]

Some damping grease may help that craft from an early death.

[@drdrhelmut]

@@Kabab I guess I should try 🤔

[@phiveone]

Flossing, boss!

[@dronepilot260rc]

This makes me want to go to a park and fly through the wooded area ❤

[@MCsCreations]

Just starting to watch, Bob, but I just wanted to say... This is the way.

[@Arthur4all]

innovating innovators that innovate! 😃

[@leonidkraljevic1263]

insane...great video

[@thrdcftyrfg7624]

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 🫡

[@Kabab]

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

[@David__]

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 :)

[@Kabab]

The single greatest contribution to the industry imo. Black out mini H. Just so ubiquitous with the early industry and classic.

[@David__]

@@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.

[@echaitea]

babe wake up kabab uploaded

[@Sugar_K]

return of he bro science king

[@Kabab]

😂

[@Starche_fpv]

This is gold

[@johncarold]

Hi Bob, WoW! I have missed your videos,

[@gloorfpv1801]

This is really interesting

[@Mavrik9000]

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.

[@Kabab]

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

[@Mavrik9000]

@@Kabab Oh okay. Thanks.

[@Mavrik9000]

@@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.)

[@onemanmob6756]

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..

[@Kabab]

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

[@ryanmcgowan3061]

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.

[@genericfpv2464]

Better late than never, love the April fool's commitment

[@israel963]

10:48 oooooh pretty! Yeah, that’s fantastic for anything running filters - it’ll decompose really easily under an FFT transform!

[@Kabab]

That's my expectation

[@ParrotFPV]

Most editing Bob has ever done

[@Kabab]

Dude, seriously! And when I started this video this morning I told myself I'm just gonna talk and not edit. Holy hell where is the Edit GPT function!?

[@patrickradcliffe3837]

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.

[@Kabab]

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.

[@cyberides]

This is the WAY!!!

[@noscadefpv4954]

teaser at the end? wow!

[@jasonwoods5725]

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.

[@Kabab]

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

[@throttlenerd]

Thanks maaaan!

[@Nici619]

yessss a new video

[@steelrainfpv3383]

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.

[@Kabab]

Something like that is always helpful but the FC is so low inertia it can only resist higher frequencies

[@k1ortia]

Chris Rosser is the man when it comes to frame resonance ..😉

[@Kabab]

Sure, resonance. What about the rest of the vibrations?

[@k1ortia]

@@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. 😉

[@Kabab]

@@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.

[@k1ortia]

@@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..😊

[@Erosennincss]

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?

[@Kabab]

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.

[@MrStevegibb]

I keep meaning to try out an idea I had with basically getting spare arms trimming the end off and using no more nails double sided tape them along the entire legnth to the original arms. This tape is extremely strong and once fully bonded will be very hard to break but you could put something around the arm to act as a stop to limit how far the top arm can move during impacts etc to stop the core ripping apart. Maybe some loops of fibreglass tape loose enough to allow movement up until the point of ripping the tape construction.

[@Kabab]

I haven't seen things taped or otherwise attached with an adhesive to the arm to be useful. They may improve durability but I wouldn't expect it to be any help with vibrations

[@kieren7763]

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

[@Kabab]

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.

[@cdog3257]

Soft copper tubes absord resonance very well.

[@mikebergman1817]

For sure. Copper is light too.

[@Tensho_C]

i used to solder the esc cables to the FC (with thicker cables), and just remove the mounts completely from the FC. The FC was completely suspended just by cables. that worked.

[@Kabab]

That's actually a really good way to go if you can get it to stay consistently. I do this often to test things to see if vibrations are an issue.

[@miquelmarti6537]

Thanks to your insistment I started to water floss my tooth. I never could stand the filament, hopefully water is good enough.

[@Kabab]

Whatever you use is the best thing. Floss is the best but a water flosser is absolutely fantastic if that's all you'll use regularly

[@ThePolymath1]

An old engineer told me; ‘to remove all vibration, one must remove all mass… however this is physically impossible.’

[@KevPV]

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.

[@Kabab]

That's what I'm hoping is happening...we'll see

[@lalilaloe]

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

[@ariafpv]

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

[@KevPV]

@@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.

[@ariafpv]

@@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

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.

[@Kabab]

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.

[@torchwork8651]

Check out vibration dampening setups on bows and their strings.

[@Kabab]

Someone else mentioned that. Super interesting for sure

[@beargillium2369]

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 😮

[@perstaffanlundgren]

Steel cabels are often used as springs for vibration damping Cradles for science equipment during transportation.

[@REDhlg]

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!

[@Kabab]

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.

[@REDhlg]

@@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…

[@Kabab]

@@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.

[@paint4pain]

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.

[@Kabab]

@@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

[@FPVLIFE]

This is the way

[@Kabab]

This is the way

[@Happyflyhigh]

I once bought by accident a bag of rubber washers used in FPV. Since I had 100s, I just started putting them between the standoffs and the top plates on all my quads, because I keep hearing about resonance running through quad on videos, seemed like a damping opportunity. I can say, I rarely see jello, and I tune really well, so maybe that goes together, but it hasn't hurt anything either.

[@Kabab]

It can actually hurt a lot. It's difficult to tell without testing it. Could help too. Definitely very hard to say it always helps. Especially if they're rubber with rebound. Also, they're definitely making the frame weaker. Gives them a stress point

[@yedey101]

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.

[@Kabab]

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

[@ekap123321]

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.

[@Kabab]

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.

[@ekap123321]

@@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.

[@Kabab]

@@ekap123321 definitely good input. Thanks for testing.

[@timetuner]

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

[@Kabab]

Right. Would love to slip something between carbon plates but it doesn't really work out since we always tighten the screws anyway

[@Ugly_Baby_Gaming]

race engines have two springs on valves with different strength's to stop resonance. so if you have your main arm how you want and a second that is different thickness/ attaching to a different point etc... the straight arm dose this as the change in frequency from the arm and body before getting to the fc as one has length and one has twist

[@Kabab]

Tried this. Many times. Totally sound argument and I thought the same many many times but it just doesn't work out as expected. I totally thought it would reduce the vibration because the two arm bits were so different....

[@SniperUSMC]

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.

[@SukSukulent]

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

[@Kabab]

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

[@ItsNonyaBusiness]

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?

[@Kabab]

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