The Copter:
Frame: Hobbyking X666 with double motor mounts
Motors: SunnySky X2212 980kv
ESC: Afro ESC 20A Simonk
Props: GemFan T-motor style 13x5.5’ Carbon
Battery: 2x Turnigy Nano-Tech 6000mAh [ 5700mAh measured from 4.2->3.6v]
FlightController: Pixhawk with Arducopter 3.1.4
Controller: 9XR
Reciever: FrSky D8R-II Plus + PPM Encoder
It was a never crashed build until today. It was moderately new, having between 4 to 5 hours of flight.
The Pilot:
I’ve started flying multis around an year ago, since Portugal has nice weather and I can fly at walking distance from home I’ve hundreds of flight hours already. I’m quiet used to build multis, I’ve built and flow quads, hexas, octos (I really need a tri!!).
Usually I fly with KK 2.0 boards (so used to Acro/Stabilized modes) or un-Autonomous boards of the sort, Pixhawk is the most advanced controller I’ve had the chance to fly. Due to my area of work/study I had no problems getting used to it and having it flying properly.
The Accident:
I flew around one of my usual spots for around 11minutes. Since I got the 30% battery warning and my voltage was already at ~10.6 I was heading home. The whole time I was flying the rig fpv. Neither the low voltage onboard alarm (set to 3.5v per cell) nor the Pixhawk voltage alarm (set to 10.6) made any sound.
What I felt was a loss of both power and attitude, I didn’t had fast enough reflexes to change from AltHold to Stab but I did give it full throttle. The craft went down either way. Luckily it felt in 1m high tall grass so not even a single prop broke, the only damage done was my home made aluminum landing gear and my GPS post, I ended up losing my FVP TX antenna top but who cares…
The video:
(Jump to the last few seconds to see the fall or enjoy the whole trip)
Comments about the video:
- Loss of power (no motor sound)
- Pixhawk turn on sound
- Motor rotate for a little bit (?!?)
- Puff ground.
After Crash Photos:
Some thoughts:
Upon inspection craft looked okish. Only thing that cough my eye was that my XT60 parallel connector was loose from the ESC input, I don’t know if it either happened because of the fall or it mid flight (less likely... do XT60 come loose ???).
When does the Pixhawk reboot? I’ve it powered by both the power module and the ESC UBEC to have power redundancy. If one of this power sources fail (for example the ESC UBEC) does the board reboot (this would be really weird...) or it keeps on running from the power module power?
I couldn’t find anything wrong on the logs and that’s worrying me...
Logs here:
https://www.dropbox.com/sh/h8cwwbet29twdyk/AADf2S2yHU3EhovAa2wXVcU5a
I need help analyzing this crash since for the first time I don't know for sure what went wrong.
Replies
Props are defenetly to big for that setup,Huges might have right...heat......Also,why do you have all the red wires from ESC connected???also do I see Mobius camera on your multi,check around web for how much noise she producing and interference with GPS,who knows what else....
Disconnect all the red(+) wires....newer power Pix or APM from ESC but from dedicated 5V BEC....
+1
My opinion that adapter could be cause of reboot.
you need remove the heat shrink and check the weildings
the best thing is to buy separate components (xt60 male fmelae AWG12 silicon cable) and create the adapter you.
Ciao - Giuseppe
Well that is definitely the wrong way to power anything up. It should go:
Batteries > Parallel adapter > Power Module > ESCs
Not that the way you have it hooked up would cause the problem directly though. Something must have a poor connection to cause a loss of power for a split second.
It sounds like it lost power midair, and rebooted - a connection falling apart could very well do that.
The log end suddently, before attitude problems, indicating a power loss.
the XT60 is most likely cause - besides - a well soldered wire would not part with the connector that easy.
Well it definitely rebooted. The beeping sound is the power up sound.
Why do you have double powered ?
For redundancy, OK, but... are you sure double powering (power module + ubec) is right for pixhawk ?
Pixhawk does support elettricaly this configuration ?
I don't know this answer, but my opinion it does not seem right.
Ciao - Giuseppe
seems lost powering connection on fly.
From log: Pixhawk turn off and no longer recorded logs .. on fly (alt and all other log stopped to above the ground)
My opinion: You need to carefully check the powering connections (XT60 male - female soldier etc.)
Ciao - Giuseppe
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