Hi,

I put a set of tmotor 2203.5 motors in my iflight green hornet v3 cinewhoop. Running gemfam 3052 props. I have tried two different ESCs and both result in desyncs. I have tried a speedybee 45amp 30x30 esc (new version speedybee sent me for testing) and a budget blhelo_s skystars esc. The speedybee will occasionally desync on sharp flips or rolls and the skystars won't go over 70% throttle without all 4 motors desyncing. The desyncs on speedybee are short and I can usually recover. The skystars esc death rolls.

So to summarize - 2 ESCs with similar issues. Anyone had issues with these motors before?

This is a high kv 6S setup. 2850kv motors on 6S. I am running a 1000uf 50v low esr cap.

On the Speedybee ESC I had the following settings which helped but still had some desyncs
Rampup power - 20%
Motor timing - 27 deg
PWM frequency - 48 kHz
Demag compensation - high

Here is a link to blackbox and dvr footage.

https://onedrive.live.com/?authkey=%21AP...7435EC1C59

whats uaw of the build?
if heavy for 3inch, above 300g, i would suggest to hive it a short try on another battery.

you can also raise the motoridle speed a bit or set dynamic idle. you can also "not touch zero throttle" while doing a flip, to figure out low rpm and speed up issue at that rpm value as the issue. hide that rpm value would help than.

(03-Apr-2022, 03:08 PM)hugnosed_bat Wrote: whats uaw of the build?
if heavy for 3inch, above 300g, i would suggest to hive it a short try on another battery.

you can also raise the motoridle speed a bit or set dynamic idle. you can also "not touch zero throttle" while doing a flip, to figure out low rpm and speed up issue at that rpm value as the issue. hide that rpm value would help than.

I tried raising the idle to 15% and didn't do anything.

I don't have a scale to weigh but it's on the heavy side. I just realized that when I remove the gopro it flies fine. No issues. I had jury rigged the gopro mount because I didn't have the three screw mount it's supposed to be used with. I wonder if gopro is moving around on flips causing it to wobble? Or perhaps it's just too heavy? I can hold full throttle for several seconds without desyncs. It's only on flips and rolls that it doesn't settle. Does that sound like weight moving around or a quad that is just not powerful enough doe the weight?

the system fails if there isnt enough power to increase the rpm. as example in a hard 180deg turn, a prop can even spin backwards from the force, to get incontrol does require much power. full throttle isnt the difficult task, it wont fail there.

the first thing i would suggest is 24khz, its more powerfull and can be the edge for that particular rpm area.
you allready did the right things on motortiming and rampup power. seems you cant go higher with motortiming, not sure if you can try to go lower.

the issue could still be noise in the system as you mentioned the gopro as possible source. doublecheck the cap connection. also check the frame about atiffeness.
the other thing is power to weight in particular rpm area, as you told you doesnt have it without gopro, i would suggest to go for 24khz and do hard moves flips and rolls with gopro and without as try.

these motors are huge for 3inch, they need a lot rpms to provide the trust. while these motors are able to spin 7inch, 3inch does require a few times the rpms to get the same trust than the 7inch - that could be the main issue. maybe you van decrease the startup power/rampup even more.
3052 is a high pitched blade, a more lightweight blade could help or fewer blades would decrease the needed rpms for trust, that could be either a solution.

the main thing, 3inches with huge motors and gopro arent well suited for freestyle. these sort of build are tanks, their only benefit is to be able to carry weight and from that weight they can fly very smooth. there is a trend for 3inch cinewhoops but they are often used wrong, they are worse for freestyle in anyway:
while you still can try a few things like 24khz and other rotors, if you plan to do flips and rolls, general improvement would be stepup to more rotor lenght; 4inch/4,5inch/5inch

i guess the answer isnt truly power issue, its more of a speedup rpm issue, but that is also related to the weight and rotorlenght. the main issue seems to much weight and to big motor for the rotorsize.

Apart from PWM set to 24 khz, I will also suggest bumping up motor timing on the ESCs. Also try bumping up demag compensation.

(05-Apr-2022, 10:49 AM)hugnosed_bat Wrote: the system fails if there isnt enough power to increase the rpm. as example in a hard 180deg turn, a prop can even spin backwards from the force, to get incontrol does require much power. full throttle isnt the difficult task, it wont fail there.

the first thing i would suggest is 24khz, its more powerfull and can be the edge for that particular rpm area.
you allready did the right things on motortiming and rampup power. seems you cant go higher with motortiming, not sure if you can try to go lower.

the issue could still be noise in the system as you mentioned the gopro as possible source. doublecheck the cap connection. also check the frame about atiffeness.
the other thing is power to weight in particular rpm area, as you told you doesnt have it without gopro, i would suggest to go for 24khz and do hard moves flips and rolls with gopro and without as try.

these motors are huge for 3inch, they need a lot rpms to provide the trust. while these motors are able to spin 7inch, 3inch does require a few times the rpms to get the same trust than the 7inch - that could be the main issue. maybe you van decrease the startup power/rampup even more.
3052 is a high pitched blade, a more lightweight blade could help or fewer blades would decrease the needed rpms for trust, that could be either a solution.

the main thing, 3inches with huge motors and gopro arent well suited for freestyle. these sort of build are tanks, their only benefit is to be able to carry weight and from that weight they can fly very smooth. there is a trend for 3inch cinewhoops but they are often used wrong, they are worse for freestyle in anyway:
while you still can try a few things like 24khz and other rotors, if you plan to do flips and rolls, general improvement would be stepup to more rotor lenght; 4inch/4,5inch/5inch

i guess the answer isnt truly power issue, its more of a speedup rpm issue, but that is also related to the weight and rotorlenght. the main issue seems to much weight and to big motor for the rotorsize.

Thanks for the thorough response. I'll try 24khz PWM. Never thought to try that. The motors are big but they are high kv 2850 and I'm running 6S so I would think RPMs should be sufficient no? However, like you said, power to weight ratio is an issue. Honestly, I bought this mostly to cruise around close to people not so much for freestyle. But part of my tuning process involves doing flips and rolls. I relocated the caddx vista so I can secure a gopro mount with 3 screws. See if that helps matters at all, along with the 24khz pwm.

I'm now wondering if I should increase rampup power. I almost always lower it to 25% out of habit. But since I'm running 3" props I'm wondering if those props can spin up faster than say a 5" with a higher rampup power? Or will that just cause more electrical noise?

(05-Apr-2022, 01:43 PM)kafie1980 Wrote: Apart from PWM set to 24 khz, I will also suggest bumping up motor timing on the ESCs. Also try bumping up demag compensation.

Thanks. Yeah motor timing is already pretty high at 27 deg. I'd be cautious about going any higher incase I get a stuck prop on a crash. But thanks for the suggestion. I have played with demag compensation as well and it didn't seem to make much of a difference. I'm beginning to think the quad just doesn't have enough power for the weight

i dont understand startup/rampup enough. uavtech does name high startup as a source for desyncs. unusal combinations like huge motors on small props or the opposide are known as different about startup power needs.
as these motors can spin 7inch which requires high startup power, most other motors in that size cant spinup a 7inch blade; i beleive decrease startup/rampup is the right direction. you might burn the motors on a very wrong value, high might be dangerous.

2800kv on 25v volt would give something like 70000 max rpms in theory, on a 5inch typical max rpms are much lower. to generate the needed trust after a flip, the motor need to increase its rpm very much, that could be an issue on regular esc settings, more weight does require even bigger rpm changes.

(05-Apr-2022, 07:44 PM)hugnosed_bat Wrote: i dont understand startup/rampup enough. uavtech does name high startup as a source for desyncs. unusal combinations like huge motors on small props or the opposide are known as different about startup power needs.
as these motors can spin 7inch which requires high startup power, most other motors in that size cant spinup a 7inch blade; i beleive decrease startup/rampup is the right direction. you might burn the motors on a very wrong value, high might be dangerous.

2800kv on 25v volt would give something like 70000 max rpms in theory, on a 5inch typical max rpms are much lower. to generate the needed trust after a flip, the motor need to increase its rpm very much, that could be an issue on regular esc settings, more weight does require even bigger rpm changes.

Thanks. I'll play with it. I ended up getting a kitchen scale to weigh the drone. So the cinewhoop is 350g without battery or gopro. With the 6S 1300mah battery and gopro it shoots up to 680 grams and that's without adding a case to the gopro. Think that's too heavy? Should I just buy a smaller battery?

If you think the setup is too heavy then try flying without a Gopro as a test for a few sessions to see if it still desyncs.

1300mah 6s is way to big. compare the wh; 1300mah 6s would be same as 1950mah 4s pack.
on 4s up to 1300mah is common 3inch big motor settups, a 6s 850mah would have the same wh. i guess your 6s lipo should be 550mah-850mah.

(07-Apr-2022, 03:57 AM)hugnosed_bat Wrote: 1300mah 6s is way to big. compare the wh; 1300mah 6s would be same as 1950mah 4s pack.
on 4s up to 1300mah is common 3inch big motor settups, a 6s 850mah would have the same wh. i guess your 6s lipo should be 550mah-850mah.

Gotcha. Yeah it's just the battery I had for my freestyle drone. I ordered a 1050 R line to see if that helps. I'll go smaller if it still has issues. Thanks!

(07-Apr-2022, 12:44 AM)kafie1980 Wrote: If you think the setup is too heavy then try flying without a Gopro as a test for a few sessions to see if it still desyncs.

Without a gopro it flies great. It's with the gopro when it starts bobblung after flips and "desync". I think now it's not a real desync. Just the PID controller and motors not able to keep up with the weight.

pids cause hot motors, heat up to damage. wrong pids makes a quad unflyable everywhere.

freakout on the end of a flip is a desync, it can come from noise about your gopro mount or from the heavy settup. likely you reach the limit of your motorabilities about providing trust.
doesnt seem to important overall, if the settup works on smaller battery, the system will have a more easy task about everything; esc(desync) and pid work. you will get better ability for pid tune. a very heavy settup does need very high pid values in general, very high p and d values, on a smaller battery you will get way better performance by lower values.

let us know how it turns out :-)

(08-Apr-2022, 10:45 AM)hugnosed_bat Wrote: pids cause hot motors, heat up to damage. wrong pids makes a quad unflyable everywhere.

freakout on the end of a flip is a desync, it can come from noise about your gopro mount or from the heavy settup. likely you reach the limit of your motorabilities about providing trust.
doesnt seem to important overall, if the settup works on smaller battery, the system will have a more easy task about everything; esc(desync) and pid work. you will get better ability for pid tune. a very heavy settup does need very high pid values in general, very high p and d values, on a smaller battery you will get way better performance by lower values.

let us know how it turns out :-)

Well I gave up on the motors. I think in one of the many crashes I got debris in between the bell and the stator. I ran the motors tab on betaflight and one of the motors started smoking. Surprisingly it actually worked better after that. However, I'm still getting desyncs. I've tried 3 ESCs (speedybee 45 A, skystars blheli_s, and tmotor velox 45 A) with a variety of settings. However, I still can't get rid of the desyncs. I decided to get a set of Xing 2205 2300 kv. The lower KV should make it easier for my ESCs to keep up.

If anyone has successfully used the tmotor 2203.5 2850kv on 6S with a 3" please let me know what ESC you are using. If anyone has any other suggestions please let me know.

Thanks!