Hi friends.
i built large quadcopter with x9 plus motors and 14s batteries. i used AMC. Followed every steps. After take off, it suddenly fell on to arm and flipped.
my setup is:
Cuav x7+ pro
Neo 3x gps
14s16p li-ion battery pack.
x9 plus motors with 36inch propellers.
auw 32-35kg.
Here is the log file and vehicle zip file.
What exactly do you think the problem is? Where am I making a mistake? @xfacta
Neither .bin log nor AMC .zip file is present.
Sorry. İ forgot to paste it 
link shared
It looks like a physical issue, the copter is trying to yaw as you increase throttle as if the motor mounts are slightly twisted.
The other thing to check is motor layout and spin - send a video of the copter arming and disarming so we can see the props turn then stop. Or do the MissionPlanner motor test and choose All in Sequence.
Set these, unrelated to the crash but for safety and better logging:
FENCE_ENABLE,1
LOG_BITMASK,180222
Disable the notch filter at the moment, it’s not quite correct anyway:
INS_HNTCH_ENABLE,0
We will know more when the copter gets airborne and we can set real values.
And start with these PIDs:
ATC_RAT_PIT_D,0.004
ATC_RAT_PIT_I,0.11
ATC_RAT_PIT_P,0.11
ATC_RAT_RLL_D,0.004
ATC_RAT_RLL_I,0.11
ATC_RAT_RLL_P,0.11
ATC_INPUT_TC,0.20
ATC_LAND_P_MULT,0.8
ATC_LAND_R_MULT,0.8
ATC_LAND_Y_MULT,0.8
Consider changing to the spring-centred throttle if your transmitter allows it. There are significant advantages for these larger copters (not so much for small acro quads)
Thanks a lot.
İ uploaded video to gdrive.
We need .bin and the AMC zip file.
Enter the parameters @xfacta suggested in the step 16 amc file. Disable the notch in step 19.
Spin direction is OK in that video although we cannot tell if motor order is OK.
I’ll think some more and let you know what I come up with - until then put in place the things I already suggested and check those motor mounts for PRECISE alignment.
They’re all in the link I shared.
İ double checked the motor orders, motor mounts and alignment before take off. They were all perfect.
Imo this is motor order / orientation issue and poor compass calibration which cause yaw rotation at takeoff.
i checked motor order and orientation before flight. Perhaps copper busbars effected internal compass. FC is positioned 9cm above the power supply line. i will disable internal compass and use external compasses. This can correct the error in the compass, right?
Do you have the log of the event in the video? The log you posted doesn’t show it flipping on it’s back and grinding in the dirt.
It’s not being calibrated. I entered the PWM range correctly.
there were only 2 logs. i uploaded both.
Well, if Log 08 is this flip event shown in the Video it quit logging before it flipped over. The log only shows a pitch/roll of <10deg. So perhaps there was a power problem to the Flight Controller. How is it getting power? The Board voltage (POWR>Vcc) looks odd. This is usually stable.
I don’t think it’s motor order as around the 39s mark it’s in a very short hover. Wrong motor order would cause a flip or spin as soon as it leaves the ground.
You can see here just before the AccelZ spike from the landing gear strike it was in a short hover. Then it bounced off the ground and the log ends. But of course right after that it flipped over and chewed up some ground.
Yes it was short take off. The drone lifted off the ground. Then it touched down to ground. Then, as it increased the throttle, it suddenly flipped over.
You can see at the video. drone is tilted to motor B. Then, to balance it, it suddenly applies power.
İ m using pover module for feed the FC. The Vcc fluctuation might be caused by the PM. But I’m supplying pm with 58.8v. max pm voltage is 62v.
A log ending abruptly usually means the Flight Controller lost power. Then of course it will crash. Vcc was dropping with a low of 4.5V. Which actual power module?
I’ve had this happen to me as well. Just flying fine than out of nowhere it just falls out of the sky. No indication in the logs, just an abrupt stop. I was running a cube orange with the kore carrier board. Big mistake… I learned that day that one of everything is not enough.
Going forward, you should add a secondary power module just for backup power to the FC. In the case of a catastrophic failure mid flight, like an ESC, it will still go down but the FC will keep recording the evidence to let you know what happen.
İ m using CUAV CAN PMU Lite Power Module with cuav x7+ pro. İ m not using current monitor because of high total current. İ m only using a power module to see the voltage and feed the FC.
