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Servo Jitter

#1
I have an issue with servo jitter
I am using Emax ES08 servos with an Orange R615X receiver on a 4ch plane (FT Simple Cub) as a three Chanel plane ie Rudder Elevator and throttle all works fine no jitters. As soon as I add the ailerons one in the aileron port and the other in Aux the initial setup is OK but after a few inputs into the aileron all hell beaks lose with all servos jitering and the motor cuts out. I have swapped over the servos but same result. This also happens when the transmitter is off. Any ideas ??

I have read the other post but they seem slightly different as to what happens to my model.
 

LitterBug

Troll Spammer
#2
Almost sounds like the BEC does not supply enough current to run all the servos at the same time and is browning out.

What ESC/BEC are you using, and have you swapped that out? Have you tried using a seperate ubec that has a higher current rating?

Cheers!
LitterBug
 

Merv

Well-known member
#3
I agree with @LitterBug, sounds like the Rx is browning out.
You could try it with 3 servos, just to see if it makes a difference.
You could try adding a capacitor to the Rx.
I suspect the solution is more amps from the 5V power supply. Either a stand alone BEC or a different ESC with a BEC that has more amps.
To have any chance of success with 4 servos, you need 3 amps as an absolute minimum, I always use 5 amps.
 
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#5
I am using a 20A ESC which I haven’t swapped out I will give that a try. Thanks
Almost sounds like the BEC does not supply enough current to run all the servos at the same time and is browning out.

What ESC/BEC are you using, and have you swapped that out? Have you tried using a seperate ubec that has a higher current rating?

Cheers!
LitterBug
I agree with @LitterBug, sounds like the Rx is browning out.
You could try it with 3 servos, just to see if it makes a difference.
You could try adding a capacitor to the Rx.
I suspect the solution is either a separate 5 V power supply or an ESC with a BEC more amps.
With 3 servos it does the same but if I set it up as a 3 Chanel it’s fine two servos and the throttle.
 

BATTLEAXE

Well-known member
#7
I just looked at your first post again, any 20 amp ESC seems to small for the Simple Cub no matter what motor you put into it. Do you have a 30-40 amp ESC to try?
 

BATTLEAXE

Well-known member
#13
I would still say the ESC is to light for starters, that's an ESC that is used on the F pack meant for 5g servos and small surfaces at max. You will want at least a 30 amp.

Do you have any video of what you described I you first post, I have had this issue before just running two servos...
 

Hondo76251

Well-known member
#17
I had a bad servo cause a similar issue once. Similar setup, didn't really have enough power from bec I was using and one servo was drawing a lot more power than the others after a few seconds of use. I didnt know that so I installed a separate bec and that seemed to cure it, until it was airborne and the servo failed completely! Lol
 

BATTLEAXE

Well-known member
#18
Yea between the lights and the servos it is definitely the ESC is to small, guaranteed my friend. Upgrade the ESC and your issue will be solved, maybe even a separate BEC for the lights too
 
#19
I had a bad servo cause a similar issue once. Similar setup, didn't really have enough power from bec I was using and one servo was drawing a lot more power than the others after a few seconds of use. I didnt know that so I installed a separate bec and that seemed to cure it, until it was airborne and the servo failed completely! Lol
That’s something I want to avoid !!