From Stabilize to Loiter Super Simple copter crash

I changed mode from Stabilize to Loiter Super Simple,
Motor #4 go to minimum,copter make looping and crashed.
Why motor #4 go to minimum?
Here is DataFlash
43 6.1.1980. 9-19-08.bin (810.2 KB)


I am not expert in log analysis, but here are some questions :

  • did you fly near a big metalic pole ? around the time you switch the magnetometer get a big change
  • did something hurt you copter ? as a little after switching to loiter, the controler cannot maintain the pitch … maybe you lose a propeller or something ?

You have disable the arming check, that is a bad behavior because it prevents to have to fly safely by detecting potential issue before flying !

1-Copter fly on sport airport 140 m from metalic pole for windsock, it’s big distance for mag interference,
2-nothing hurt copter
3-May be I made mistake because i put FS_CRASH_CHECK=0 for unlimited angle of flying ?

I was refering to ARMING_CHECK parameter

I know that I disable arming check.O.K.
but FS_CRASH_CHECK=0 is something another.
may be this is reason for copter looping.


Is this perhaps one of the first times the copter has been flown? It looks like the vehicle is perhaps very badly tuned. Even before the switch to Loiter we can see places where the roll angle is off by 8 degrees.

The RATE messages in the dataflash also show that the vehicle is not rotating at the desired rate. I suspect the ATC_RAT_RLL_P/I and ATC_RAT_PIT_P/I values should be increased quite a lot. Perhaps double their current value. Tuning is tough to do remotely but I think the values are too low. By the way, normally it’s good to raise or lower P/I and D together. So if P and I are increased by 10% then also raise D.


You are right,this is one of first times the copter has be flown.
This is QuadTailsitter, my experimental construction, as in photo.
I may not find code for QuadTailsitter without ailerons,elevons,elevators and rudder,
but I think that it may fly without this!
Maybe you have some idea how to arrange this with Tailsitter code.
For first experiment I try with Quadcopter code.
First crash was with PIDs as in photo.
Now I will put Roll P =0,255 and RollI = 0,255.
What you think?