Flyaway... What the heck happened?!

[unclejismad]

So I recently built my first quad. My setup was:

FC: Mamba f405 mk2 with 4-in-1 ESC
Motors: Racerstar SPROG 2206 2300kv
Rx: Frysky XM+
VTX: Eachine TX805 5.8G

Everything went smooth with the build, and I was able to successfully fly the quad about 5 or 6 times without any issue.

My most recent flight though went completely wrong... I got my quad up in the air and flew away about 60-70 yards, when all of the sudden I completely lost signal in my goggles and I heard the quad shoot straight up into the sky at maximum throttle, even though my throttle stick was almost all the way down. I ripped my goggles off to look for the quad in the sky but by that time it was so high up I couldn't see it, I could only hear it screaming a full speed farther and farther away. I was flipping switches and moving sticks on my controller but it didn't do anything. Eventually I just completely turned my controller off, causing the quad to eventually fall somewhere. I looked for the quad for a long time and drove around many blocks but never found it.

Anybody have any idea what the heck could have caused this to happen? I had the failsafe on my controller set to "no pulses." I hadn't had any crashes or problems in my previous flights. My mind is boggled that this randomly happened and makes me nervous to build another quad.

The only thing I can think of that could have possibly caused this is the fact that my soldering wasn't perfect. Like it wasn't bad, but it also wasn't perfect like I would see on youtube videos. I can't think of anything else that could have caused this to happen.

 

[John Scott]

Was this a GPS drone? I'm not certain of or familiar with your build but if GPS enabled it should have not flown away. I'm guessing that if you had GPS off or it wasn't a GPS build it was taken away by wind. If wind is 5 mph at the ground it is much stronger at 400 feet in the air. I know that if I take my drone out GPS my drones will quickly take off in the direction of the wind very fast at 400 feet. I have always been able to bring my GPS enabled drones back by enabling GPS and they will return to the GPS launch point.

 

[Dugdog47]

I can't say for certain but it was probably a faulty flight controller that is weird though sorry to hear about your lost kwad.

This is one reason we shouldn't fly these tiny high powered flying blenders around people because stuff happens sometimes out of our control.

 

[wafflejock]

Yup could have been the PID loop got into some sort of runaway where it keeps causing more and more error and over corrects until it runs out of control. In latest versions of Betaflight (think anything after 3.3) there's some things that are meant to stop the possibility of such a runaway soon after take off but it could still happen I suppose. Really without black box logging after finding the quad it's hard to guess what went wrong (even then takes some detective work and extrapolation), but guess that's part of the reason to get an FC with black box logging and activate it. Also could have been faulty IMU or something knocked loose etc. Since your video went dead maybe some voltage spike in the electrical system caused it to go out. Can say it sounds like a fluke though I've built and flown plenty of dodgely soldered quads without issue obviously more careful you are with making and testing connections the better but still as the wise dugdog says stuff happens.

 

[Dugdog47]

Don't use the mamba fcbs they have issues.