Servo Jitter

Tony1717

New member
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

Techno Nut
Moderator
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

Site Moderator
Staff member
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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BATTLEAXE

Legendary member
Does the same issue happen if you use a Y connector for the ailerons, just to eliminate possibilities?
 

Tony1717

New member
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

Legendary member
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?
 

Tony1717

New member
Do you have a picture of the ESC label? This does not sound like a good ESC to use.

ESC and motor
4F5A1B62-80CE-4CB8-BD45-B22DDD44CDAE.jpeg
 

BATTLEAXE

Legendary member
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

Legendary member
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

Legendary member
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
 

Tony1717

New member
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 !!