Joshua Bardwell's Analysis of my FPV Rekon 6 crash | What happened ???

[@j.c.matteson7449]

My guess is a glitch desync temporarily on front right motor, and then when the FC tried to correct it you just happened to be too low. If you were up higher I'm guessing you might have saved it.

[@MattShonan]

Really could be, just the strange thing is that it gets more and more into a nose dive. That means both front motors did not produce enough thrust. One I can understand but both is difficult to explain. Also the inconsistency that the front right one spools up and recovers but then the front left one seems to be lagging behind with thrust creating that strange banking from right to left and back to the right before it nose dives into the water. I hope the re build I am working on will be just fine. Have a great day and happy flying!

[@muhkuh0816]

looks a bit like the time my lipostrap failed and the lipo keeps dangeling around. but that was on a small toothpick with lipo on the bottom, not topmounted where it would probably cut the powerleads immediatly ...

[@MattShonan]

Never thought about this. Yes, seems that could explain such a flight behavior, however in my case here the battery was wet mounted, on top, with 2 battery straps. Therefore it is highly unlikely that the battery moved creating this issue. Happy flying and have a nice day!

[@alloutofdonuts3998]

I was thinking a birb clipped it at first too but unless it just barely hit it, it didn’t seem abrupt or violent enough. Even a light hit seems it would’ve spun out(yaw/roll/pitch)more. If you had gps rescue then most likely wasn’t a failsafe/Rx loss. I assume vid was lost right as the clip ends, just before going into the water? I had 2 quads do something very similar to this twice in the past year. Neither time I lost video at all, but it was on land. 1 failure was due to a component blow on an AIO. The 2nd failure was due to a cold solder on the negative lead at the XT60 end. It flew maybe 6 fights before it started having issues. I found it was the connection after wiggling it a few times. On the bench I could see a crack and was able to separate it with a few more wiggles(like a baby tooth). BEFORE anyone says that’s a rookie mistake, sure. It is, but it doesn’t mean it never happens with those that are experienced. I’ve been soldering for a long time. Longer than I’ve been flying & building quads(about 5-6 years now)and I’ve built dozens of quads. I’m not trying to brag, and I realize a person can do something a long time, doesn’t mean they’re doing it CORRECTLY. Just to point out that I’m not a noob at soldering or building quads.😅

[@MattShonan]

Yes, my reflexed accidentally disarmed, that is why the last frame is before it hit the water. Sorry to hear about your accidents, hope next year will go without "uncontrolled" losses. ;) Good luck, happy flying, thank you for your comment and have a great rest of the day! Hope you enjoy the content coming up on my channel.

[@baggszilla]

I'm thinging short desync front right motor then when FC tried to correct other motors desynced. It is frustrating I feel your curiosity.

[@MattShonan]

Yes, really frustrating especially because I am now a bit gun shy flying over water loosing another one. Because I can not know for certain what happened that uncertainty will fly with m for some time I think. I hope it will fade soon so that I can be more confident and trust my equipment 100% again. Thanks for the nice words and have a great day!

[@SOLARFPV]

This happened to me once. The stator was loose and would turn with the bell all of a sudden and stall the drone like that. But at lower speeds it would stll fly. Took me some time to figure out, and must have happened after a crash. Getting the drone back to check it would be the best way to find out.

[@MattShonan]

Among all really valuable comments on my video here, yours might be the one hiding the nail on the head!!! I was flying the FPV Cycles 21mm I love those motors but they ha some issues with their supplier before switching to uni-bell design. I never thought about how it might look like if the bell gets loose but it totally makes sense. Not a bird after all?!? I really have a spike in motivation now to dive down there to get it back finding out what happened to the motors. I want to rebuild the quad and planning to use the exact same motors. If they were creating this issue, I would need to know for sure before flying long range over water. Thanks again for your comment and have a great day !!! Happy flying :)

[@SOLARFPV]

@@MattShonan Thank you Matt... who knows what went wrong... you should deffinately try get it back, just for the sake of it. If you were using 18650 battery pack... they are magnetic 😉 so you could magnet fish it. Then you just need a boat ride 😄 good luck with the new build.

[@MattShonan]

Thanks you for the good wishes, I hope I can get it sometime in the weeks when the weather is good. I need no to almost no wavers, calm waters.

[@creationlabsinc.189]

@@MattShonan how deep of water would you say?

[@MattShonan]

Well, really difficult to guess. There are 2 stacks of those concrete blocks and one layer is at least 3-4 meters. About a 6-10m dive I would say.

[@Sylo2Nice]

Its crazy bro. Me and my friend went down in the water as well. I have flown in the river i was at before but decided to go to the other side with my friend. We both was flying. We both build our own quads. Both also using crossfire. He went down first and me a couple of seconds later. We both still dont know what went wrong. Both builds used expensive parts. And i have flown mine about 100 times. He only used his 3 times.

[@MattShonan]

Sorry to hear about your quad losses. Well, it is part of FPV that this happens at times. Hope you can find the energy to re build you equipment and keep enjoying this great hobby. Thank you for the nice words and have a great day! Hope you will narrow down what went wrong in your case so that this is avoidable going forward.

[@dooddrones6521]

Not a bird strike. The initial roll to the right/pitch down wasn’t violent enough. There clearly wasn’t an impact. Had to either be a mechanical issue with that RF motor, a desynch from that ESC, or maybe a gyro that was starting to fail.

[@MattShonan]

Thank you for the comment! I think you are right and really now believe that the "bell" was the issue and became loose.

[@A1phaZu1u]

Do you have pictures of the build? It honestly looks like your battery fell off and was dangling off the left hand side. Could have been that your battery strap failed.

[@MattShonan]

Yes, I actually shared the build video > this one here kzbin.info/www/bejne/r3rWeH1ndpmfm80 And also the maiden flight which went very well > this one here kzbin.info/www/bejne/rWiZkq17ptBoi5o Thank you for your comment, it really seems that it looks like this when a battery is loose. Someone else made a similar comment regarding this and it was his experience as well. However, in my case I was using 2 straps PLUS a brand new Ummagawd, Ummagrip super sticky battery pad, which alone would hole the battery without battery straps in place. Also my battery is mounted on top and if it shifted it would very quickly hit the rotors and then the quad would spiral into the ground. If the battery is mounted at the bottom of the quad this could be a more likely scenario. Well, I more and more feel I have to dive down there to get is back to finally have clarity. Thank you very much for your comment and have a great day! Happy flying :)

[@A1phaZu1u]

As I suspected your power leads are on the left hand side of the multicopter. I’ve had batteries slip out of the heat-shrink before, so even if you did strap that battery down well it’s still a possibility. I’ve flown a quad home after having the battery slip out before, it’s very similar looking to the way your drone was behaving. It could have been a number of things and even if you recover it you will likely never know what happened due to crash/water damage. Good luck.

[@MattShonan]

Yes you are right, it is possible and I can not totally rule it out. I was strapping the battery leads in at least under one of the two straps when I actually fly. That was not the case in the build video, I do not fly like this but got a bit lazy when I made the bench photos and videos simulations the actual flight configuration. What makes me believe it was not the battery lead though is, that they are on the left side. However the first error in flight was lading to a dip to the right. For triggering that event the battery leads would have to be on the right side getting in conflict with the engines making them loose thrust on the right leading to a right dip. Weather is cold right now but I hope for some calm days in December to dive down there, littered getting to the bottom of things :)

[@dizlovesart]

I had some crashes like this. I discovered it was my rc left gimbal sudden twitches. I have to replaced my gimbals to avoid another crash.

[@MattShonan]

That you for your comment! Well, in my case I am flying the Radiomaster TX16s with AG01 gimbals. I don't think that the AG01s fail easily but good to know that this also could be something to watch out for. Sorry to hear about your crashed and hope you can eliminate crashed because of filing gimbals! Thanks for watching and happy flying!

[@DanG-ye4rh]

If it was a birdstrike, it was probably one of those seagulls that you can see on those stones to the right of where you crashed. Seagulls attack other birds when threatened. The only other idea I could come up with is a bad solder job on one of the motor wires or a desync of sorts, but that usually shows pretty early.

[@MattShonan]

Thank you! I did not realize that the seagulls are in the shot. I was looking for things flying but not siting. Thanks for the comment! Well, I also feel 99% it was a bird strike. Have a great day and happy flying! :)

[@Sbangfpv_]

3:22 I’m a little late to the party but I bet something got caught on 1 of the props. Most probably battery strap. Exactly something like this happened to me a few days ago. A battery strap stopped rear Left prop.

[@MattShonan]

Yes it might be. I also found that there were some motors assembled with the wrong glue leading to an issue where in flight the bell could become loose. It could have been the reason as well. Have a good day and thanks for the comment.

[@TropikalSport]

Good video mate I subscribe to your channel 😉👍

[@MattShonan]

Tank you very much that is really appreciated. Hope you will enjoy the content coming up! Have a great day and happy flying :)

[@bboy1022]

Hello Matt, I was going through my recommended videos and i stumbled across the joshua bardwell video of your crash. By any chance do you happen to live in japan? I live in Kanagawa and it's this area here called Enoshima.... I'm getting really strong Oiso, Fujisawa, Odawara, Enoshima vibes from some the videos i saw. Either way I subscribed lol

[@MattShonan]

It's a great place to be, right? Hope you enjoy Kanagawa! Have a great day and happy flying! :)

[@KAREKINFPV]

Ive had this same thing happen. Pid loop error from something touching the motor. I can PM you a video that looks identitcal. But i saved it and got home.

[@MattShonan]

Yes please, share! Maybe it helps me to analyze my case. Good to hear that you could recover before things got worse and keep you quad alive. :) Happy flying and have a great day!

[@KAREKINFPV]

@@MattShonan please send me your email or find me on FB messanger.

[@MattShonan]

You can mail me here > [e-mail]

[@keithws79]

Getting hit by a bird was my oddest crash. It came out of no where. I only know it was a bird because I briefly saw it’s wing while reviewing my DVR footage one frame at a time.

[@MattShonan]

Thanks you for your comment and sorry to hear you got kicked out of the air by a bird. Hope your quad was not then at the bottom of the ocean like mine. ;) If you look at my video, can you confirm that this is somehow similar to what you experienced in that flight when you got attacked? I am still just trying to make somewhat "educated" guesses. If case my flight footage looks similar to what happened to you, well, then it would really be a wrong indication for me that this is what actually happened. Have a great day and happy flying :)

[@DriftaholiC]

Looks recoverable, easy landmarks. Go get her.

[@MattShonan]

Thank you for the motivating comment! :) I will try my best when the wether is better again. Follow up video will come if I get her back. Would be great to see the blackbox logs. Have a great day!

[@DriftaholiC]

@@MattShonan I'm sure it's cold but that's good for you! :P

[@MattShonan]

d(^_^o)

[@Inertia888]

It did look to my eyes that some external force initiated the right roll & forward pitch. The quad seemed to try to counteract that force, but could not before crashing. Bird strike seems most plausible to my eyes, as well. > This makes me think about trying to have a second person with a high magnification camera to track the quad. It is not an easy thing to do, but I think in my own personal flights, I will begin to try to practice this on flights where I feel it may be helpful. The most important part of this, would be finding a person who is good at using a long range scope, and has steady hands. The pilot and the person with the camera would have to work together and do their best to plan a flight path that makes it easiest for the camera person to keep the quad in sight, with as little effort as possible. Not an easy task, but if pulled together, would make for a very good video, as well as flight diagnostics.

[@MattShonan]

Yes, good point! The bird might have grabbed it from behind and then things happened as they did. Especially the most plausible event happened since all other options are more or less ruled out. Thanks for the comment and have a good day!

[@maddmavic]

That right prop looks alot different abgle then the left one also

[@MattShonan]

should be the same but if the bell was loose, I guess anything is possible. I will definitely try to get it back for investigation.

[@madman216fpv]

A birdstrike would have made a impact strike like hitting an object even from behind the quad, even a beak/peck strike you would have seen the moment of a strike impact into the quad itself play out on the screen.

[@MattShonan]

You are right, I was thinking more of a grab rather then just a hit from behind. Just coming up with something here since it is such a strange case and there is no definitive answer. Hope I will not start having bad dreams about this flight ;)

[@cf5073]

The same thing happened to me on the 2nd flight with a brand new Bind n Fly Rekon 6. Mine landed over land, so I can see what happened. The bell come loose from the axis, die to no or bad quality of HGRC motors. If your interested I can send picture.

[@MattShonan]

I now believe this is exactly what happened as well, thank you! Just my issue is, I actually love this motor and have another set for a re-build. I wonder if I should go for it or replace the choice of engine???!

[@cf5073]

@@MattShonan until now I did not find any motor in similar dimensions with less ore same power consumption. So I also ordered the original 2006 for replacement

[@MattShonan]

Actually I was building this Rekon 6 with the FPVCYCLE 21MM MOTOR 1620KV. It is really a great motor over all and gives me super long flight times. Maybe worth a try for your build as well. I am rebuilding mine next month and will upload the development how it goes.

[@cf5073]

@@MattShonan definitely woth a try, thanks for the hint

[@MattShonan]

please share how it goes, my build is delayed but I will upload videos as soon as it is ready later this year.

[@MrStevegibb]

Were sanity checks still enabled? As GPS rescue can disarm the drone for many silly reasons when they are enabled and I would disable them especially when flying over water. The drone looks like it cut power to the motors to me similar to when I have had drones disarm when testing GPS Rescue in the past. Remember that disarming the motors does not brake them to a stop they will auto rotate in the air. Also its best to make sure the failsafe stage 1 delay is turned off so that it goes straight into GPS-rescue instead of holding some arbitrary throttle position for a period of time. Edit : Oh another point runaway takeoff prevention has been known to disarm drones mid flight when it thinks its detected an event if your confident in your procedures then just disable it when flying over water etc. It supposed to turn off after take-off but I think it relies on the throttle going above a certain position to do that.

[@MattShonan]

You are right that is a high risk! My setting for RTH is always "failsafe only". Basically the same setting at what JB discussed in his standard setup for RTH. However, as Joshua Bardwell mentioned on this video here, we don't think can be a failsafe issue at all since the motors kept spinning. If sanity checks failed, even if they were enabled by accident, the motors would have stopped and the quad would have just fallen out of the air. Yes, I guess it would have taken time to stop for the rotors after disarming but the video was cutting out at the time I disarmed by reflex. It was just when I was about to hit the water. All what happened before is actually showing that the motors spooled up on the front right and then again on the front left trying to get out from this situation but something else went wrong at the same time. That is why I felt at first it was a bird grabbing it from behind. One comment here said it could be the bell becoming loose and this is now my other top reason I can think of. Also the reason why I seriously consider to finally take the "risk" and will try to dive down there to get it back for investigation. I really hope to avoid this from happening again since I am flying quite a bit over water. Thanks, have a great day and happy flying!!! PS > stage 1 failsafe was not active and the RTH is kicking in immediately in my long range setups. (my freestyle quads, flying in and around structures, go to stage 1 first before 2 kicks in.)

[@maddmavic]

Could the rol movements be the stick movements not realizing ur self trying to recover fast

[@MattShonan]

I can just recall being in shock trying to tilt back and gave it some trottle. It seemed to not respond at all anymore to any stick inputs. It happened just all too fast.

[@ugpfpv361]

Yeah it sucks when you don't know what caused it and is now untrustworthy, could have been a desync or even a bad gyro..., Good luck with the rebuild, bo a lot of test flights before sending it long range again.

[@MattShonan]

Thank you! I will definitely give the new build some more time over the usual terrain before sending it out over the ocean. Have a great rest of the day and happy flying :)

[@ConjoFPV]

This looks like a sort of esc desync to me. Ive had simikair events like this with a faulty aikon32 bit esc

[@MattShonan]

Well, that was also my guess at first. But then again why is it banking from right to left. Then recovering the right engine and at the same time loosing thrust on the left motor. I guess all is possible but really difficult to tell what really happened. Thanks for the comment and have a good day!

[@thepoorboychannel]

Maybe stalling out in dead air. You stated you was really moving. You can always expect turbulence while flying over water.

[@MattShonan]

You are right, I never thought about this when flying quads. I was flying gliders fro years and had clear air turbulence's out of nowhere occasionally. However I never experienced this close to the ground. But it really could be that this is what happened. Thank you for the comment. I will take other quads out in this area and watch out for this keeping my long range flights not as close to the ground as I did in this case here. Hopefully this helps ;) Have a great day!

[@madman216fpv]

Super quick desync, re sync but the fc tried to compensate but it was too late.

[@MattShonan]

Possibly, I think it could. be. Maybe similar characteristics as when a bell is coming loose. Well, if I can get it back we will see more details what was going on here.

[@madman216fpv]

I have a video on my channel showing a bell and prop flying off of one of my motors seconds before landing...it was interesting to say the least, but gave me no warning....crazy hobby this is.

[@MattShonan]

It really is! Well I think this keeps things exciting ;) Will check out your video, thank!

[@scottmclaughlin1410]

Loose screw on FC caused gyro to lose synch?

[@MattShonan]

Well, this could be but it was a new build and all crews were self locking and new. I think if is a smaller risk but for sure I only will know when I can get it back. Thanks for you comment and have a great day! Happy flying :)

[@georgitushev]

How close to home exactly crashed? We’re you flying it or was returning home itself?

[@MattShonan]

Good question, thank you, I missed talking about this in detail. I was almost exactly 370m out (on my way back). The flight was not very long. If you like here is the full flight video (including the flight right before it crashed which was very similar). kzbin.info/www/bejne/rWiZkq17ptBoi5o I was flying myself and and there were absolutely no issues visible. All OSD elements also were green and didn't indicate any problem coming up.

[@georgitushev]

@@MattShonan to me it seems to enter failsafe but because was already close it initiated descending little prematurely. Unless you set it up to 350 meters, Or your home point was established later after you take off and you locked to the minimum satellite count when you you were already out over the sea.

[@MattShonan]

Well, I had my return altitude set to max (max altitude of the flight) that should not trigger a decrease actually but trotting up. I was quite low and was about 15 meter higher earlier in that same flight. But thank you for brain storming. I really hope I can get to the bottom of this and share the outcome in one of my future videos.

[@spikester]

My guess is your ESC hit some low voltage cutoff, it does appear you had control of the aircraft on the way down, but lost ability of thrust? If this is a Lithium-ion cylinder cell then 3.7 could be too low especially after that long-term high throttle. I try to drop power and fly slower after long bursts, don't fly at high throttle for too long over water I learned that the hard way you must give it some breaks in between on the flight. Please post your ESC settings.

[@MattShonan]

All happened quite fast. I felt that is was not responding at all. I tried to tilt back and throttle up. But the quad tumbled towards the water in that strange nose dive. The propellers were spinning and I feel that the ESC might have been fine. But is is a possibility. Thanks for the comment, have a great day and happy flying!

[@spikester]

@@MattShonan Ya, its a tough one, too bad you didn't recover, you could then rule out a loose prop or desync, blackbox logs would likely be still recoverable if ya could.

[@MattShonan]

Will try to get it when the weather allows. Hope I can share what actually happened sometime soon.

[@Sir_Hubris]

Amazing, did see it on his live stream! ¶ ; - )

[@MattShonan]

Thanks for watching! Hope the footage form my next version I am working on is more enjoyable to watch. We will see how it goes. Have a great day!

[@remyKhuong]

You never know what hit you behind😭🤔

[@MattShonan]

yes

[@rickywklau01]

I lost two quads, 4 inch and 5 inch in exactly the same way. Both using HGLRC F7 flight controller.

[@MattShonan]

Sorry you lost yours seemingly due to the FCs. In my case I was running an F7 Flywoo board I had until that point never issues with. Maybe in my case it was a loose bell since the motors were known for this issue or the bird strike. I will try to dive down there getting it hopefully back soon for further investigation.

[@rickywklau01]

Both incidents happened when current drains were high, e.g. 20A, against head wind。The quads shaked left and right several times and dived into the sea。

[@MattShonan]

Understand, my situation was slightly different. It was early in the morning and the weather was relatively clam. No strong winds to fight in my case. I was just gently cruising back home to shore at the time of the sudden nose dive event.

[@timotheos0190]

Looks like a wind shear !

[@MattShonan]

Yes, it felt like. that is why I was jumping to bird attack because on that day the weather was relatively clam and it was still early in the morning at sunrise. Usually wind and gusts, even sudden once form behind were until now managed quite well by the quad. But as you say, it really could be the reason. I plan on recovering it from the water over the next weeks when there is good weather and hope I can get finally to the bottom of this. Thanks for watching and have a great day! :)

[@HelloDimineata]

There was no way to recover it I would assume?

[@MattShonan]

Unfortunately! The quad seemed not to respond anymore and all happened to fast. Well, I hope the new version I am building right now will be just fine!

[@j.c.matteson7449]

LQ > RSSI

[@MattShonan]

I am running WTF OS on the Goggles V2. In the OSD, both, RSSI and LQ were just fine. No warnings and over 10 satellites. RTH was just tested in the previous flight and it was working perfectly. Therefor this was one the first issues I ruled out for creating this sudden nose dive. Thank you for the comment and have a good day! It might have been a bird attacking the quad from behind. I guess 80 km/h was just not fast enough ;)

[@abracadaver7687]

What about a bird 🐦 ?

[@MattShonan]

Could very well be, that is on top of my list what could have happened. Really hope to get it back by diving down there to have clarity before re-building it. Thanks for your comment and have a great day! :)

[@abracadaver7687]

Birds aren’t real 🤣🙌

[@MattShonan]

It's all simulated anyways ;)

[@abracadaver7687]

@@MattShonan I Hope for you sea salt 🫣

[@MattShonan]

;)