Trying to undertand thrust level to hover via logs


I am having trouble trying to understand how much thrust I am getting from my motors, as a percentage of maximum capacity. Here it is attached a couple of graphs from the same flight.

The first one, plotting the ThO variable under CTUN, the average is more or less 0.3. According to this, I would claim that my motors are working at 30% of their maximum capacity.

The second one, plotting the C1-C8 variable under RCOU, the average is 1700. According to this, and since the range is between 1000 and 2000 PWM, I would claim that my motors are working at 70% of their maximum capacity.

Of course there is something I am not getting right here. This is why I hope you can help make me to clarify this. Finally, how much thrust I am getting from my motors as percentage of maximum capacity?

Thanks in advance,


and to make it even more interesting, MOT_THST_EXPO is affecting this too :slight_smile:

The ThO is the percentage of thrust that you are using to hover. This is translated to PWM by the battery voltage and Thrust Expo value.

Keep in mind that your minimum throttle will be 1150 and your maximum will probably be something like 1950. So the output range will not be 1000 to 2000.

So looking at your graph you have approximately 3 times your weight in thrust provided your props do not start to stall under high load.

Hi Leonardthall,

Thanks for your answer ! So then, according to the graph, my motors were working at 30% of their maximum capacity when hovering, not 70 %? Is that correct?

And another question, in which cases would you recommend to change the default values of MOT_THST_EXPO? What is the procedure to do so correctly (the documentation unfortunately is really vague about this? And would you do so in my case?

Thanks again,


To change MOT_THST_EXPO you need measured propeller vs pwm data.

So if you are happy with the tune of your aircraft there is probably little to be gained.