After a lot of success with Auto Tuning I’ve been anxious to try it out with my heavy lift copter. There was a bit of a breeze so I wasn’t sure if it would have time to do the tuning before it drifted too far away but that turned out to be the case. On my last attempt of auto tuning the copter would drop during each cycle of the twitching. The distance it would fall increased each time so finally I flicked it out of Auto Tune and back to Stabilize. The I put it in Alt Hold to see how it would go and that was doing the same drop as during the Auto Tunes. I decided it wasn’t worth continuing as Auto Tune certainly isn’t going to work if Alt Hold is flakey. I should mention that when I started flying Alt Hold and Loiter were working perfectly.
All of that aside, the real issue happened after I landed it. The copter disarmed and it was in Stabilize mode. I had a look at the gimbal etc and then moved back to take off again. When I armed the copter the motors came up to full speed and the copter flipped on to it’s back. The crash detection must have kicked in as the motors stopped shortly after flipping.
I know that the throttle was not up as I arm with the same stick as the throttle. But even that shouldn’t allow the copter to spin up at full speed. And no, this was not the props just spinning up when armed.
I’d be most interested to know what caused the copter to give full throttle and flip when I armed it. Did it have something to do with the previous Auto Tuning? Or was it related to the Alt-Hold issues? Certainly, something was not right.
Flash log attached if anyone has time to have a look at the end of it to see what actually happened.
Using a new Pixhawk with Arducopter ver 3.1