I had a crash w/ my copter and want to be sure I’m correct in my analysis.
I think it’s mechanical or ESC related.
I was flying down fast, at near zero throttle. Then began to apply throttle and the copter spun and crashed.
So, am I correct that I see motor 1 being commanded to spin. But for some reason, it looks like it actually decreases its RPM’s.
1, I’m dropping fast at an angle, so front motor being at near zero output is not unusual.
2, I apply power, and it looks like the FC wants ESC1 to start spinning, but it doesn’t.
3, I hit the ground and then motor 1 starts spinning. Short bounce, and
4, hit the ground again and stop.
Big edit above… I uploaded a graph that’s hopefully easier to see the important stuff.
If I’m correct that it appears to be ESC or mechanical, care to take a guess as to why?
I’ve encountered motor startup problems before, but it looks like it was spinning at the time. So not a startup issue, but it just didn’t start spinning faster for some reason. I’m not sure what would cause that.
Well, I assumed the RPM’s not following RC OUT was a pretty clear indication of mechanical issue, but if not, I guess I’ll upload the log. I’m trying to not post so many logs of my poor choice of flying location… It sets a bad example. If I were flying anything larger, I would not be flying where I am… But this is a little 120 gram copter, with battery. And everyone around here knows I’m the one flying them so if anything goes wrong or any neighbors are unhappy, they know where to find me.
Having said that, here’s a link to the log. It’s a mess. I was flying, landing, changing settings, doing it again, and again. You can probably ignore everything except where the issue starts around line 180.
Want to mention, I did fly again after the crash… No damage… I just looked it over and took off and flew again.
Also, this is 2s and li-ion’s, so the voltage is quite low. But that’s normal. I fly until I’m just below 5v, and then after powering off the motors the batteries settle at just over 3v per cell.
I concur, it was a stalled esc.1, sorry for asking log, but everyone likes his own analyzer, and analyzing a crash from an already established viewpoint cause bias. I like to start from zero…
Thank you, and I understand your position on reviewing logs. Good practice.
One thing that seems very strange is that the motor appears to have been spinning slowly at the time I increase throttle, and then the motor actually slows down!
Has anyone seen that issue before? I’ve seen a motor fail to start from being completely stopped. But never saw one that was already spinning have trouble spinning faster.
I have one theory which is maybe I was dropping fast enough at enough of an angle that my RC antenna got blown down and wrapped around the motor. The wire did get bent, so at some point during the crash, the props hit it.
I guess the first thing I will do is increase my motor idle speed… Just in case it was a startup problem.
