tomorrow I flied for 1st time with my fresh build hexacopter with pix (few quadros, one octo and 250 size on my account, all DIY). And I'm experiencing strange behaviour like never before in any of my copters.
When I took off (problems with takeoff too, strong tilting, needs althold start or throttle punch in stabilize) and moved roll stick aggresively copter almost flipped by counter tilt. When it was in air, it was ok, loiter, pos hold, alt hold, OK, BUT when I triggered AutoTune it almost flipped! Instant Stabilize and a bit more throttle to level my hexa. I experienced some problems of this sort, but it was always problem with PID's or ESC's.
I lowered pids to 2.5 from 4.5, also lowered I a little bit, looks stable, althold, 15m altitude, a little forward flight and center the stick... Wooah! It almost flipped trying to "BREAK?" tilt break in opossite side? Last time I've seen that it was with mine friends 250quad on miniAPM, also tilt-break, but he had strange problems with PID's and he had to unlock lower PID values in mission planner.
Now I'm asking, how to set pids on my hexa to at least safetly trigger autotune? Or maybe something else is wrong?
And LiPo's are of course UNDER centerplate, not very high above making pendulum like some of constructors used to mount.
Tomorrow I'll install maybe arduplane and again arducopter to flush eeprom and run through all calibrations and settings my OSD, FrSky, RSSI pin and few other things.
Also have strange problem with GPS when in stabilize/loiter on my one quad and this hexa, its just wandering few meters (1-3m) right left or forwards backwards with, WARNING!: 16 sats, HDOP<1m, reprogrammed with u-centre to 38400baudrate and 5Hz refresh rate! Also M8N but different PCB inside. I tried to solve this for few months touching almost every setting in missionplanner...
-Pixhawk: arducopter 3.2.1 hexa X (3DR Original, clone already fried giving 5V from usb on everything, on STM32 too)
-ZTW Spider 40A Opto
-5000mAh (or 2x) 4S 3000Ah (or 2x) 4S
-M8N GPS with compass module
-Tarot Iron Man 680Pro
I wish my quad or hexa behave like this... https://www.youtube.com/watch?v=oCGKqRqidbA
Config is almost the same with much better GPS module.
My 250 with cleanflight is more stable... no problems with other quads I've build, almost same configuration, ESC's reflashed to SimonK, motors with higher KV than 1000 flashed to BLHeli... And different pixhawks, clones/original. Only 2 copters with theese sort of problems, I gave up. Maybe its 3.2.1 soft... Still waiting for official release of 3.3