Help analyse height loss

Log Analysis -- deprecated Copter Logs -- deprecated
1

Hello

I hope some can check my logfile and help me find out the problem for the height loss. The setup is a heavy drone:

  1. Drone with 12 motors
  2. 7,5kg payload
  3. Total weight with batteries 22kg

The problem does happen at different times, the drone slowly looses height, sometimes it recovers before touching ground, sometimes it does not. We testes the payload on a rope, as soon as the payload lands on the ground, the drone recovers. Without the payload it flies fine with the full battery charge for 80min.

We checked the following parts as a source of error:

  1. Motors, only heated up to 35°
  2. ESC, also only heated up to around 30°
  3. The batteries did also not over discharge

So a problem could be some settings, we missed, because it is a heavy drone. Maybe someone can check the logs and our settings?

Logfile

thanks for any help!
christian

2

In a word - underpowered

55%20am
Screen Shot 2019-02-20 at 6.33.55 am.png2296×954 699 KB

You might also be better served by setting it up correctly as a dodecacopter rather than a hex with doubled up motors.

3

Hello Mike,

thank you for you feedback. Of course you are right with the logfile. But still a little bit strange, yes the drone is with 22kg a heavy drone, each Motor has a thrust of 3,5kg, we tested this on a teststand. This means it is a little bit under a 2:1 ratio and the coax version is of course a little bit inefficient, but it should still hold the drone in the air. Also the motors didn´t get hot, most of them didn´t reach 40°. As they couldn´t get somehow the full thrust .

Unfortunately, we can´t use the 1-4 Aux channels in this case for the motors on the dodeca copter.