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
Has anyone determined EXPO values for T-Motor ESC+Motor+Prop combinations by any chance?
Thanks a ton,
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…
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
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…
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?
You haven’t by any chance tested any Alpha ESCs?
Alpha ESCs are much better than Flame. I use Alpha on a good amount of my builds.
What thrust expo do you use for those?
0.2 has worked well for me - but it depends on a lot of factors. I use the integrated propulsion series which seems to have different expos than the stand-alone ESCs. Its a mess from T-Motor’s handling of ESC firmware and whatnot, so you kinda just have to test a couple to converge on a solid value.
I run the 605-S arm set on 6s lipo. I tested 0.2 and 0.4. Didn’t notice any difference. I also tested 0.76 (calculated value from wiki) which did not work as well and introduced some over all instability.
I also noticed there’s two different firmware’s for this motor/esc combo using the data link. Have you encountered this?
Yeah the firmware changes all the time based on when you ordered the sets. I have used the MN501S (normal and coaxial) and MN6007 packs and they all seem to work pretty well in that 0.2 to 0.4 range you specified. I always start with 0.2 and if I feel instability then I start tweaking it higher towards 0.4.