Thrust lost on motor 2 caused crash

ArduCopter Copter 4.5
1

hello,
maybe someone can help me find the cause of this crash, the copter has flown for 35 minutes or more several times before. Unfortunately it crashed on the 6th flight and I can’t make sense of the log files. The BMS didn’t work during this flight, but that can’t be the reason after about 10 minutes of flight?

The copter was not yet fully tuned, but flew quite well with the initial parameters.

Arducopter 4.5.3
Cube Orange+ and Here3 GPS
Herelink
Lumenier Elite Pro 60A 4in1 ESC
MAD Motor 5005 280Kv
17" propeller
Take-off weight approx. 3.3kg

https://www.dropbox.com/scl/fi/4qkuenuuyp1xrackixyfu/00000024.BIN?rlkey=19ebjzf8tkhafohirivdqqxh8&dl=0

2

The post should be titled Thrust Loss on Motor 2.

RCout2
RCout23354×1039 168 KB

Seems to be a problem with your battery monitor.

3

Or a cable from the ESC2 or motor2 has come loose?

4

@dkemxr Thanks for the hint!

5

Is a low KV motor with digital ESC, have you disable the Low RPM Power Protect, I experience that once before but not sure is it the same. I have to set the MOT_THST_EXPO,0.99. My motor KV is 650.

6

@Jai.GAY Thanks for the tip, low rpm powerprotect was on by default. What exactly does this setting do? I don’t think this was the cause, because immediately before the PWM value rises it was at approx. 1400

7

image
image714×208 24.3 KB

8

Here, his explanation. Maybe not related.