MOT_THST_EXPO setting for T-Motor Flame ESCs

Hi,

finished my latest build and about to start tuning.

I am using T-Motor Flame ESCs + T-Motor FA24 x 7.9 Props + T-Motor MN701S 135KV motors (all @ 12s).

I read here in another thread that T-Motor ESCs apply thrust linearisation and thus the default MOT_THST_EXPO setting of 0.65 is probably not ideal for this setup.

I have not been able to setup my thrust measuring stand / dynamometer yet and calculate the right value - there’s just not enough time for everything it seems :frowning:

Has anyone determined EXPO values for T-Motor ESC+Motor+Prop combinations by any chance?

Thanks a ton,
Christian

Isn’t the expo heavily dependent on prop design?

if so, it’s because we graph static thrust, not propellers optimal speed… most of the non-linear response is caused by ESC code/electronics if not compensated.

I just started to work on my good old thrust/current/power/voltage sensing/plotting rig to add RPM , so I’ll soon know if power curve / thrust curve / rpm curve are significantly different, and how much a change of propeller changed it…

Hi,

I completed the measurements on the thrust stand yesterday and my results are as following:

Motor: T-Motor MN701s (135kv)
Props: T-Motor FA24x7.9 (Folding CF Props)
ESC: T-Motor Flame 60 HV
Power: 12s

MOT_THR_ARM 0.08
MOT_THR_MIN 0.11
MOT_THR_MAX 0.95

MOT_THST_EXPO 0.18

I have not had a chance to fly with this EXPO value yet - will provide an update once done.

Thought I’d post her in case anybody had the same config by any chance…

Christian

Interested to see how it flies with .18. Would love to see video flying around.

Your data is appreciated, thanks for sharing. Expo of 0.18 sounds about right - I’ve heard 0.2 to 0.3 is common for T-Motor and KDE ESC’s.

Oh and just a note: the throttle expo is meant to be measured ONLY for the PWM range used in flight, ie between MOT_SPIN_MIN and MOT_SPIN_MAX. If you include the bottom and top ends that aren’t experienced in flight, the expo will be off. Just wanted to make sure you were aware of this.

On a side note, does anyone know if DJI ESC’s also linearize throttle?

We had a similar setup. We used MOT_THST_EXPO 0 which seems good enough. We did not have a thrust setup so I do not have a curve for Flame 60A. Just assumed it was linear.

Hello my bro ,
I have the same Motor 、Props and ESC with a quad , and
got some problem when auto flying . The props sometimes stop spin . maybe 1second or 2 ,looks dangerous

default setting . expo 0.65 weight 9kg

so I change the expo to 0.18 would be solve the problem?
thanks