The drone will take off and fly perfectly for several minutes, and then it will control and crash.
Log 7, drone took off, flew forward, and when I yawed to the left, it lost control and came down in a semi controlled manner and crashed.
Prior to that flight it had been flying OK.
I have been testing and the latest flight, was going perfectly for 6 minutes and then started to lose control. I managed to land, but then it flipped over.
I assumed it was something with the compass, but I am no longer sure.
Seems to be an intermittent thrust loss on Motor 3. And you have a lot of default parameters; Notch filter not configured and you have the Bdshot version of firmware flashed but not configured. Some hardware problem and basic configuration and tuning.
In Log 7, motor 1 had the same intermittent issues. Either way, the crashes are a mechanical problem, not a software issue. Check power distribution, prop mounting, wire harnesses.
Yes, there is room to improve the tune. It is running the default tune for 11 inch, and it flys pretty well. I have to get this issue resolved before doing any autotunes, etc.
Following your suggestions, I pulled the drone apart, but couldn’t see any damage to the wiring to the motors, and the soldering looked OK. Couldn’t see any issues. I replaced motors 1 and 3, to be on the safe side.
Below is the log from the test flight. Took off and drone started yawing to the right (CW), then started pitching and rolling, so landed.
The log showed the F/C maxing out motor 3, but it wasn’t. There is the message, Potential Thrust Lost, but there wasn’t.
After landing, the motors powered down (as they do), but then increased in speed, not responding to the throttle. It all ended with me unplugging the battery.
Is this a flight controller or ESC issue? I can generally work out what is happening, but this one has me beat.
The RCOU values are only showing what the FC is commanding, not always what the ESC is seeing or doing. In this case it’s clear the FC is commanding full power as you’ve seen, to provide some kind of stability correction, but the FC is not seeing any kind of result from it. As such it’s giving the thrust warning because all it knows is it’s asking for max thrust but it’s not getting it.
It’s a Motor or ESC isssue. Also check wiring and other physical connections. Don’t overlook prop security.
I didn’t see any effort to disarm the drone (but I may have missed it). Either use a switch (the fastest) or you can use rudder disarming.
For disarming switch it is recommend to use either Motor Emergency Stop or Arm/Motor Emergency Stop. Former will stop the motor immediately and disarm after few seconds, later allows arming with the same switch.
Arm/disarm and disarm switches immediately and unconditionally disarm the vehicle. If that happens in flight it is unlikely that you will be able to arm again.
Off topic here, but does no one use motor interlock as the first “stop motor” step? If it is accidental it can be re-enabled, otherwise has the same effect as emergency stop. Or am I missing something?
As @LupusTheCanine mentioned, it’s used on trad heli. On my helicopters I actually use rudder arming then a switch for the interlock. On multirotor, I feel that the arm/motor stop gives the same overall functionality without the need for two different inputs.
I do the same on mine. IMHO we could use a 3pos switch that does three things
HIGH - try to arm then raise interlock
MID - interlock low
LOW - motor emergency stop
For this to work really nice
Motor Emergency Stop needs an option to trigger motor brake even if it is normally disabled (applicable to small direct drive helis)
Interlock down starts spooldown sequence of main motor (coast command or controlled throttle reduction) and doesn’t shut down tail rotor until main rotor goes below minimum RPM
For ICE (including turbine) MES should immediately command idle (clutch disengaged throttle setting) followed by emergency shutdown after configurable delay to minimize damage to the propulsion unit.
I’ve noticed an interesting benefit (at least for me) with the Arm/MES on a 3-pos switch. When the switch is in the middle it does nothing. This is good because during pre-launch the switch can be moved to the middle position and that will stop the GCS from chirping a pre-arm warning about the motor stop. Likewise in flight, if the switch gets bumped to the middle the only thing that needs to be restarted is the heart of the student and the drone continues unaffected.
I like your suggestion for heli. It would give the same work flow for heli as in MR.
Two detents and you’re going to hit the motor emergency stop and you can go back to high with the switch and the motors will restart. So if you altitude and reaction time are in your favour you might get away with it.
