XAircraft What esc are you running with pancake motors and superx

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Tommy Luhr

Member
Hello!
I got a tarot fy690, a fresh build that i am tuning right know.
I can start with my spec:

multistar 3508 14pole 700kv engines
13x6,5 propellers
Afro esc 30amp with a beta firmware for pancake motors (2013-10-29) SimonK.
3s battery
superx controller at 1,2 on all gains but height is 1,0 in gain.

I got 16 mins of flight time in windy weather with 10 000mah battery and used 9000mah. That on AUW 3200grams.
That is alright i think.

Problem:
The motors twitching and jitters like the gains are to high. But if i lower the gains the tarot becomes so slow in response and almost unable to fly.
Stil the twitches is there. The ringing sound in this motors tells me that the engines not works as they should!

I'm think this is all on the Esc. I want to try another Esc with superx and this motors.

What do you think about XL30a esc that is Xaircrafts own?
As i understand, this is a regular signal and not the ultra pwm esc?
Im i wrong here? There are so bad info on this at all stores!

Just want something that works vell. It has not to be the simonk firmware (even if that firmware was very nice to fly) but it has to be a good controller that never fails on my rig.

Sometime the afros make the frame hexa tilting just after take off, think this is a sync issue on startup!
This setup is not reliable enough to make relaxed flights with all that expensive equipment that's planned.

Please share your ideas!
/Tommy
 

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Electro 2

Member
Turnigy "Plush" 40A with HengLi 4822, no issues. "Ringing" is normal. This is the fundamental chop rate of the ESC's PWM action, usually 8kHz.
 
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Tommy Luhr

Member
Good to know! i hard tested the afros yeasterday after aligned the engines a little bit better. They seam to work pretty ok right now. The ringing sound is more like it's "over gained" like a nervous sound.
It proabably to lightwheigt witout the camera.
It flies 8min 30 sec on one 5000mah battery and almost twice on two 5000mah 16 min and 40 sec.
Throttle at hover with two 5000mah packs is right over 40% (no camera). Mabye the engines running to slow and some sort of ocilation in the system appears.
 

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Electro 2

Member
Tommy Luhr said:
Maybe the engines are running too slow and some sort of oscillation appears in the system.
Click to expand...

All this and more awaits in your Black Box file for the test flight. Flight system instability under some flight conditons shows under "gyro angle rate" and motors too slow (overpropped)/too fast (underpropped) would show under motor drive level figures. One of the many advantages of the Super X. Send me the link and I'll be glad to help you wade through it, if desired.
 


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Electro 2

Member
Tommy Luhr said:
Very nice that you want to look at the log :)
http://log.xaircraft.com/#2014_02_06_044609.750_49.1.08.41
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A few things visible here. (I'm presuming we're looking at flight #49, the final in this log) The present props are good to go, average motor drive is in the 50-55% range. I personally prefer a scootch higher, but that's *my* preference, not what's design optimal. Also, there is a noticeable discontinuity between the CW and CCW motor groups drive levels. The most likely cause is either motors are not mounted orthogonal to the boom plane, ("true"), or props are poorly made, yielding a thrust difference between CW and CCW designs. This has been known to happen with some brands of plastic props. I personally have never seen it, but others have reported this. Vibration is too high at 1-2 G. XA recommends lower than 1, both of my birds hit less that 0.5. Something, somewhere, is out of balance or just plain loose. Props again ?? Dealing with the combination of these things could sweeten the performance.
 

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Tommy Luhr

Member
I would switch my 6,5 propps to 5.5 instead today. The rc timer 6,5 is not good in pitch. when i spin the blade it got different height on the tips of the propeller. Around 5-10mm. Thats not a good propp.
This propellers are mounted with a regular propeller hub. The Multistar engines have not the most well balanced propeller hubs.
I will go back to 5,5 and loss much vibration, gain a littel hover rpm. It does not get much lower flight times.
Do you know if there is any 13" 6.4 propps with t-motor style center?
 

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Electro 2

Member
Tommy Luhr said:
Do you know if there is any 13" 6.4 propps with T-motor style center?
Click to expand...

Do you mean 13 x 6.4, or what? If so, that's kind of a high P/D ratio for a multi, especially for a 22 pole motor. Most 13 inch props intended for multis have a pitch of 4.7 or 5 inches. One 13 inch, (X 5 inch) that I have used is the Xoar woods, and they're really good. True, and virtually no vibration once balanced. No, they're not cheap, but you get what you pay for. I'm currently using the Xoar 14 x 5 on a 1000 with the HengLi/DYS/Foxtech/Turnigy W4822 motors and it's divine.
 


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Tommy Luhr

Member
Here is todays flight:
http://log.xaircraft.com/report.htm#2014_02_08_070727.500_54.1.02.18

Look at 62 sec, one motors drop out (or more) and come back.
This things happening sometimes and usualy early in the flights. This thing i direct pass ower to the esc.

I got different "ringing" in my motors every time i fly them and they fights alot when i am running at some speed. It´s very bumpy in the fpv cam.

I think i'm done with this afro ESC now. On the last 3 startups i got one of them not fire up as the others.
Do you guys recomend Plush esc or should i get some dji optos?

Im clicking in to hobbyking and look for some better ones. Or any good links here?
 

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Electro 2

Member
Tommy Luhr said:
Here is todays flight:
http://log.xaircraft.com/report.htm#2014_02_08_070727.500_54.1.02.18

Look at 62 sec, one motors drop out (or more) and come back.
This things happening sometimes and usually early in the flights. This thing i direct pass ower to the esc.

I got different "ringing" in my motors every time i fly them and they fights alot when i am running at some speed. It´s very bumpy in the fpv cam.

Do you guys recomend Plush esc or should i get some dji optos?
Click to expand...

Sure sounds like ESC issues of some sort. Impossible to diagnose by remote control, from here. Vibration is down and CW/CCW motor groupings are tighter though. Tends to negate the possibility of a frame/build issue. No experience with DJI ESCs, so I don't know.
 

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Tommy Luhr

Member
I bought Turnigy plush Esc. Hope they work out well.

Against the uneven motor outputs it must be the propps.
This time i'm using rc-timer 13x5.5" props with t-motor mounts. I got all motors perfect leveld but still som uneven outputs.
Can this uneven outputs be some sort of esc problem.
One esc or more got same signal as others but respons are different.
I don't give much for this Afro esc right now, i like the simonK firmware but the glitches don't belong to my build.
I drive this multi very slow and just for movie and som nice fpv shoots sp there are no need for super fast response.
I will come back here when i have drive it with turnigy Plush esc!
 


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Electro 2

Member
Tommy Luhr said:
Have to tune (out) some vibrations, but some new props will do that for me, I think!
Click to expand...

Agreed. It's OK the way it is but I routinely see an average of 0.4 with peaks of 0.8 or so. Prop size looks OK as motor drives are in the 45-55% range. I prefer a somewhat underpropped condition with drives running in the 48-58% range over the length of the flight. Also sometimes this condition results in slightly longer flight times as peak-to-average motor currents are tighter. Motors are reasonably true also, as the CW/CCW groups are well matched.
 

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Tommy Luhr

Member
Hey!
I will keep fighting with the numbers:)
Thank's for the help with the language, It goes a little fast sometimes when i write. I just translate the Swedish sentence in to English.
But the sentence structure is not the same so some words would drop off and some new would drop in.
This is a great way to get the English graspable
 

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Electro 2

Member
Tommy Luhr said:
But the sentence structure is not the same so some words would drop off and some new (ones) would drop in. This is a great way to get the English graspable
Click to expand...

Understood, and not even remotely the same as most Scandanavian languages. To make matters worse, there are many colloquial phrases and words-that-aren't-words, used on these forums. Easy for a native speaker to grasp, a total mystery to a non-native speaker.
 

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