Im not sure if it was my fault, or something else, but my quad dropped when I switched flight modes the other day. I believe that the log shows that my throttle input when to zero when I switched flight mode, but I dont remember doing that. I usually leave throttle at the center, so Im a bit confused as to what really happened. I just want to confirm that I dont have any power or component issues and could use some help analyzing the log.
I had some compass and EKF issues, so that day, I had performed a compass calibration out in the field, before this flight, so I also want to confirm that this had no involvement. However, within the log, I see that one of my ESC RPMs went way too high, and Im not sure what to make of it. Im pretty sure my ESC params are good because the motors dont get hot and the craft flys good, but Im worried about that ESC. They are raceday single ESCs, and Ive never had a problem with them, so Im confused why it behaved that way. Here is a screenshot of the BLHeli32 params Im using: esc setup page, esc overview page.
Root cause is your disabled the throttle failsafe, this causes the resulting crash when all RC channels go to nothing (RC link is lost).
At a basic level the flight mode is switched to Stabilise while the throttle is at nothing - actually much less than 1000PWM , more on that after… So the quad does what it’s told and becomes a house brick.
In this graph you can see battery voltage rises as the throttle drops, and voltage sags as you try to recover by raising throttle - I was looking at the battery voltage in case it was an issue, but it appears to be behaving normally and is not the cause.
The real problem is throttle goes below 1000PWM which shouldnt normally happen. To me this indicates an RC link failure, which should have initiated a failsafe and RTL.
It’s probable the mode change to Stabilise was also linked to the RC failure - it depends on what transmitter and receiver you have and how failsafe is set up.
Looking further you will be able to see all RCin channels go to 875PWM at the same time, confirming the link loss AND incorrect failsafe behaviour.
and read up on your transmitter and receiver failsafe actions. Ideally you could set “no pulses” or something like that. The other (old fashioned) way is for all channels to return to set positions which is not usually desirable for a multirotor. The older-style receivers resume the channel positions as they were when bound to the transmitter - this needs special consideration.
If you are getting frequent throttle failsafes or link losses then that’s an issue to be solved, and should not be masked by changing the throttle failsafe parameters.
