Auto mode Spiral of death

Hello guys
After about 100 autonomous flights my 1900 skywalker decided to crash.

He entered the death spiral and could not save it because I could not see it on the mission planner.

During the time that he worked he had three death spirals being able to save it twice turning off the automatic mode and manually piloting this time I could not see it because it was far away.

Now I need to set up another SkyWalker 1900 but I need to know why this happened.

Could someone help me with the log files?

Log files;



In it I used the following components;

Skywalker 1900 frame
Original 3DR PIxhawk With gps / compass module
Digital Airspeed Sensor
Align DS415M Digital Servos
Engine - Tmotor
Futaba radio
RFD 900 telemetry
HobbyWing xrotor 50A ESC
Samsung camera for photogrammetry.

thank you

Beautiful area that you fly in!

The spiral happened just as your aircraft turned after reaching a waypoint. Your right wing must have stalled due to a combination of aggressive turning and quite bad wind conditions. Unfortunately the autopilot will just make the situation worse by trying to get the wings level again. A good RC pilot knows to get out of the stall first (keep nose down) and then to level out, as you have done on previous occasions.

I’d look at your RLL2SRV parameters, more specifically RMAX (maybe start with a low-ish value and increase until you get a reasonable response) and perhaps decreasing P.

Also, during normal manual flight, you don’t use more than 2000 points (20 degrees?) of elevator, and in auto flight that is reduced to less than 1000. I think you can safely reduce your elevator up authority by half (set SERVO2_MIN to 1300), or even more, which will reduce the ability of the autopilot to pull the airframe into a stall. You may not be able to do as much aerobatics then :slight_smile: but it appears that your airframe is a workhorse anyway.

More experienced pilots may be able to give more info, but this is where I’d start.

Good luck!

ARSPD_FBW_MIN = 9 is too slow for this frame ! 12-13 should be minimum depending on AUW and of course higher if it’s heavy. If you want to fly as low as TRIM_ARSPD_CM = 1200 decrease LIM_ROLL_CD.
For mapping purpose, it’s interesting to set MIN_GNDSPD_CM in case of wind. During this mission you’ve got 10m/s wind sometimes. (We had this frame and found that on calm day it’s a beauty but with wind more than 10m/s what a nightmare …)