Hi, see inline below
[quote=“MickeM”]Ah, I could have created a new .LOG from the APM, if it wasnt loaded with new firmware to get the RCIn’s and RCOut’s? Or is there any other way? Must find that wiki…
Unfortunately it doesn’t work that way, the various log types need to be enabled before flight before they are any use…you can’t enable them post flight to add data. Its difficult to recommend what logs are critical to log. The APM can struggle if all are enabled. I suggest RCOuts are enabled though at least for a few flights.
At the crash, there were a FlySky-radio (Turnigy 9X lookalike) and a FrSky 4-channel receiver with ppm used, not mine, maybe it is sold now… could have looked at them.
The ESCs are 3DRobotics:
store.3drobotics.com/products/e … p-SimonK-1
They were assembled on the X8 when sent from 3DRobotics.
I really hope they have disabled cutoff… but we should double check.
ah ok…I imagine they are multicopter specific then, which should men no cut offs.
DJI mean the nose jumping up and down when flying forward appears if it is nose heavy.
CG are always checked before flight with the battery.
OK
There have been other flights with the exactly same current peaks, followed by problems like descendning and wobbling. Something isnt right. Have happened on another multicopter. The diagram (for Current) shows a very smooth curvy line and suddenly these peaks that are straight. Strange.
I think the straight lines are due to the update rate being quite slow, the lines just join the points. Wobbly descents are pretty normal for multicopters…if well tuned its shouldn’t flip or crash…but its just the way they are…descending down though its own turbulence is harder for it.
We heared that the X8 struggled with the wind (more motor-sounds) all the way when it flew against the wind, but nothing spectacular.
Yes I may have fixated on the current peaks more than the crash, thats right. Sorry for that. I thought they appeared for some reason because those peaks appeared on earlier flights also with following problems. Peaks were not always in the end of the flights.
some flights might not show current peaks if it was all smooth and easy. It’s easy to get fixated sometimes…don’t worry about it. Its good to try and solve it and suggest things, I should have tried harder to work out why it crashed in the first place rather than just looking at the current.
The X8 frame are not symmetrical, pretty dumb construction, at least I think that. Not mine:
40.media.tumblr.com/3ef77389c5d9 … 5_1280.jpg
Stable left-right but not so stable front-back.
asymmetry isn’t necessarily a bad thing. My DIY builds generally are symmetric though. But it probably does mean you will need different PID values for pitch compared to roll. Are they the same? (I haven’t re-looked at the log to check)
The X8 flipped forward, we thought, and the .KMZ-file shows it too.
The 3DRobotics APM 2.6 is powered with the 3DRobotics Power Module:
store.3drobotics.com/products/a … connectors
- Power to PDB and to motors.
- And a different cable to power the APM and RC.
One big problem here… the servos were also powered by the PM (same as RC and APM). Its “illegal”. =) And could have caused problems. The gimbal couldnt make the servos bind.
The X8 have its own Castle Creations UBEC now.
as you say runninf servos on the same power PM power is a bad idea…glad you sorted it
One LiPo on the X8, a Zippy 4S 5000mAh 25C.
The log ended after it crasched, look at the picture earlier in this thread, when the battery was disconnected. Or is it at 10m… The X8 fell from 130 meters and landed upside down in the soil/dirt. Nothing broke besides 4 props and 2 motors bearings sounded bad, GPS stopped working (dont find sateallites anymore) but looks fine.
OK, if the brain switched off causing the crash, the log would have ended at 130m. Maybe it landed on higher ground than where it took off? See further info below
Havent done any AutoTune, dont know how to do. Will try on my DJI F450 with APM (test platform).
Its not too hard…read the wiki
Brownout FAIL? APM I guess. Is that because of the low cell-voltages? Or one of them. Remeber this problem have occured earlier on other multis (3DRobotics Hexacopter) that may have had the same battery (“flight pack”).
No not the cell voltages. This is power to the brain being lost. The automates test is quite simplistic in that it just tries to see if the copter is at the same or close to the same altitude as where it took off. If say the copter brain loses power at altitude, the log stops at that altitude…not ground altitude. Its just a simple method to try and detect issues…sometimes the automatic tests generate false fails due to the simplicity of the check…but they are useful none the less.
What does PM = FAIL - 9 slow loop lines found, max 16.80% mean? Slow loop lines?
I havent figured that one out or seen an answer yet…I have seen a few people post asking about it recently.
IMU Mismatch = UNKNOWN - No IMU log data? Is that because of problems with accelerometer and/or gyroscope?
It doesn’t indicate a problem, just that there isn’t any data to look at as it wasn’t enabled in the logs.
If the ESCs cutoff stopped the motors because of too low voltage, then it is pretty logical it flipped… I will check all ESCs if I can find a manual for the ESCs. Even thou voltage was recovered. And I will check if reduce power is active on the ESCs.
Check it all over, but on an X8 ideally if a motor is lost it should cope…ideally at least 
. The reason I build a DIY x was for the redumdancy if a motor failed. On one flight one of moters stopped and I almost missed there was an issue other than seeing one propeller not spinning. I suppose a badly tuned copter may still crash though. I also guess if the battery is really flat it may not cope…but I would think this would manifest itself as losing height but level…but I guess in extreme cases a flip could occur.
The temperature were +4 degrees Celcius at the time.
This is very interesting. =) And big thanks for your time. There are three multirotors used and they all have their personalities.
Would be boring if they were all the same
(sorry if my grammar isnt correct, swedish is my native language…)
No need to apologise…your english is infinitely better than my swedish
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Hope you get it sorted!
