I am new to this forum, I hope that I'm posting in the right place. I'm also new to quadcopters and I'm seeking help related to flying my very first quadcopter, or more specifically related to the problems that I've been encountering while flying it.
So, my very first quadcopter is the FQ777 F8 GPS Monster Drone. It has lots of nice features and a decent camera and my first few flights were OK.
This morning, however, it gave me a good scare. I started experimenting with flying it around in large circles (about 200 m wide) by slowly continuosly pushing the right joystick in circles. It was all fine, but at some point I lost FPV connection with my phone, could not see where it was, so I called it home using the controller's Return To Home button. It came home fine, but then, instead of hovering over the takeoff position, as usual, it started flying around it in small circles (1-2 m wide) on its own, with no input from me. I tried bringing it down, to land, but it started flying in larger and larger circles, uncontrollably. Eventually it was going around in circles as wide as 50-100 meters, almost hitting trees and buildings and nothing I did on the controller could stop this. It was responding to throttle (rise/come down and rotate nose), but not to the right stick (move left/right/forward/backwards). This went on for about 5-10 minutes, convincing me that I have lost it forever. But I was lucky. Eventually the low battery emergency return to home kicked in and it returned home again. It semed to stay stable above the takeoff position, so I thanked God and quickly landex it.
I have noticed this behavior at least 3 times, that after RTH it hovers for a short while above the takeoff position, but then it starts flying around in small circles. However today those circles became dangerously large and it was a miracle that it did not crash.
So my question is: has anybody experienced anything like this with a quadcopter? Any idea what is causing this? Any idea how to prevent it from happening? I tried searching the internet but could not find anything relevant.
I have figured it out. The circling out of control happens if you mess with the controls while the drone is doing a RTH. When you call it home, it doesn't immediately hit the exact home spot, but it comes within a 5-10 m range of it. Then it starts circling it in smaller and smaller circles until it hits the exact spot. You can see the distance on the controller. If you interfere with the controls during this process, sometimes it goes crazy and wonders off in large circles. So after a RTH do NOT touch the controls until the controller shows exactly 0 distance! After that it begins it's descent and at that point it's safe to interrupt the RTH process.