This is my first airplane setup. I am using a X9d+, with a r6 receiver and Tower Pro 9g servos. The servos seemed to work fine before gluing them in the plane. Now they are quite jittery, they do not sit quietly at neutral. I checked the servos with a Spektrum setup and they are very smooth and quiet. Can anyone tell me what I can do? I did rebind the receiver in ACCESS 1-24 channel (24ms) but still jittery. Thanks.
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My servos are very noisy and jittery
- Thread starter cedar
- Start date
Konrad
Very Strong User
The Tower Pro 9g is an analog servo
The OEM claims to now have a digital servo. Funny they couldn't be bothered to change the call out, SG90
As to noise with FrSky try moving the Rx antenna away from the servo leads The FrSky telemetry is likely being pick up by the servo leads.
If you have enough servo lead try tying some knots into the lead. This can sometimes cancel out noise on the leads.
The OEM claims to now have a digital servo. Funny they couldn't be bothered to change the call out, SG90
As to noise with FrSky try moving the Rx antenna away from the servo leads The FrSky telemetry is likely being pick up by the servo leads.
If you have enough servo lead try tying some knots into the lead. This can sometimes cancel out noise on the leads.
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Thanks to both for the replies. The noise is from the servos trying to center and they cause the flight surfaces to move back and forth about a 16th of an inch. Sort of like the old "galloping ghost" radios of the past. Showing my age. I don't usually use these very low cost servos so I guess I am wondering if I just need to install higher quality servos?
Konrad, I don't understand the "call out SG90"?
Konrad, I don't understand the "call out SG90"?
Konrad
Very Strong User
Nether do I ! The OEM is calling ether (both) servo an SG90. The nomenclature is the same for both servos. Are the links not working?
It's not a servo issue if you can get quite servos with brand S but FrSky is noisy. I think this comes from the fact that analog amp can't filler the RF noise on the servo leads. Unlike the old days the 2.4 gHz RX is also a transmitter. Try the tricks we used in the old day of 72 mHz when forced to run long servo leads, say in glider wings.
P.S.
But yes in today world is is best to use digital servos. Corona and E-Max have some very good economic 9 gram servos.
It's not a servo issue if you can get quite servos with brand S but FrSky is noisy. I think this comes from the fact that analog amp can't filler the RF noise on the servo leads. Unlike the old days the 2.4 gHz RX is also a transmitter. Try the tricks we used in the old day of 72 mHz when forced to run long servo leads, say in glider wings.
P.S.
But yes in today world is is best to use digital servos. Corona and E-Max have some very good economic 9 gram servos.
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Oh, you have given me some great ideas to check out. The brand S does not have telemetry. I think there is also a way to shut off the telemetry to test your theory. Yes I do remember the little glitches I had trouble with in the old days of long servo leads with a 72mhz AM radio. Thanks so much for the help. I am really excited to learn more with this new radio.
I guess I am not very clear on the issue I am having. Yes this is just a foam glider to test the reliability of this new radio. There is no slop in the linkage and the longest servo lead is about 18 inches long. The servos are actually moving the surfaces. All of the electronics are new/unused but of course the servos are several years old. From what Konrad said I am now using a telemetry receiver where my old dsm2 receiver was not. I have no problem using some of my newer digital servos if that is what is needed for this newer system. I am sorry that I ask a lot of questions. Thanks all for the discussion.
Konrad
Very Strong User
Nothing to apologize for. That is why the forum is here.
I need to warn you that digital servo have a buzz that guys moving from analog to digital servos often find disconcerting. This is what Henny was getting at. But this buzz should not result in surface movement, unlike the noise on an analog lead.
I need to warn you that digital servo have a buzz that guys moving from analog to digital servos often find disconcerting. This is what Henny was getting at. But this buzz should not result in surface movement, unlike the noise on an analog lead.
Hi, I have some new information on this problem. When it first appeared I had not installed the receiver, esc or battery. They were just laying on the bench. While thinking about this I mounted the receiver with the antennas separated by about 2 inches, one vertical the other horizontal. During the process I found that the issue was not consistent. Well as I kept testing I found that if my aileron lead was next to or touching the antenna I would get the elevator and rudder servo moving back and forth a little. I am still working to find out how much distance I need to have. I have never had this issue before but it is the first time I have had a telemetry system too. I am now looking for antenna installation ideas. Thanks for any advice.
Konrad
Very Strong User
Is there is noise on the line (antenna from the telemetry)? Remember the telemetry means that the RX is a TX!
An analog servo can't withstand the constant input from noise.
Please go back and practice sound installation practices, particularly with analog servos. Most say to try to keep the antenna 50mm from any metal. As a stop gap try to braid or twist your servo leads. Most hight dollar servos have twisted leads rather than flat ribbon for this very reason, Noise cancelation.
An analog servo can't withstand the constant input from noise.
Please go back and practice sound installation practices, particularly with analog servos. Most say to try to keep the antenna 50mm from any metal. As a stop gap try to braid or twist your servo leads. Most hight dollar servos have twisted leads rather than flat ribbon for this very reason, Noise cancelation.
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Some servos have no filtering and they do not do well with telemetry receivers. In general such servos should be avoided.
A quick fix, turn off the telemetry, I do think that would work. I have also seen people wrap the servo wires and servos in aluminum foil with some success.
A quick fix, turn off the telemetry, I do think that would work. I have also seen people wrap the servo wires and servos in aluminum foil with some success.
Scott Page
Very Strong User
This is a really late entry to this discussion -- but putting a small ferrite on the servo leads will generally take care of this problem.
Konrad
Very Strong User
Braiding the servo leads is a time honored way to cut down on noise. I was surprised at how much wire length this takes up! The tighter the braid the shorter the wire. In real life I find that twisted servo lead wire is just as effective as braiding. Flat ribbon wire lead is to be avoided.
Now the proper fix is to buy high quality servos. But should these develop noise going back to the twisting leads is a good practice.
Now the proper fix is to buy high quality servos. But should these develop noise going back to the twisting leads is a good practice.
Scott Page
Very Strong User
This brings up a question. Some ARF's - such as the Freewing Avanti use flat ribbon cable from the wings to a distribution board. If the wires are twisted or braided at either end will this prevent inductance issues?
Konrad
Very Strong User
YES!
Please beware that braiding will shorten the lead length about 8% to15%.
Off Topic:
Please re-servo any FreeWing or Flightline airplane! Just about every FreeWing model I've had has suffered a servo failure within the first half hour of use! I strongly recommend the use of a servo tester to burn in these low grade servos for at least 5 minutes. This has caught most premature servo failures.
Some background. These Freewing servo failures go back to 2014 and cover both analog and digital servos. My understanding is that Freewing changed OEM around 2016. I have not seen an improvement in servo quality.
Here is a partial list of my Freewing collection: (code OB= On Bench, OG= On Ground, IF=In Flight)
2 @ Me 262 (steering 9g and aileron 17g failure, OB, OG)
3@ SU35 (rudder 9g , stab 17G, OB)
3@ F5-E (Flap 9g, rudder 9g, OB, IF)
F14 (17g elevator 17g, IF (crash airframe loss, amp failure caught on video)
P51 1.4m ( Gear door 9g, IF [Crash BEC shut down from servo fire])
P38 (aileron 9g, OG (Servo fire, amp failure)
The Me 262 and SU 35 are from the earlier servo OEM, I think these were also analog.
Not to sound too negative I've had a few Freewing with no servo failures; two 64mm Stingers, One Mirage 2000 and one of those SU35. Also the best flying Foam EDF I've seen is the FW 80mm T33.
Full disclosure: MotionRC is so pissed with me (Customer service and engineering issues) that they will not sell to me. No real loss on my part.
Please beware that braiding will shorten the lead length about 8% to15%.
Off Topic:
Please re-servo any FreeWing or Flightline airplane! Just about every FreeWing model I've had has suffered a servo failure within the first half hour of use! I strongly recommend the use of a servo tester to burn in these low grade servos for at least 5 minutes. This has caught most premature servo failures.
Some background. These Freewing servo failures go back to 2014 and cover both analog and digital servos. My understanding is that Freewing changed OEM around 2016. I have not seen an improvement in servo quality.
Here is a partial list of my Freewing collection: (code OB= On Bench, OG= On Ground, IF=In Flight)
2 @ Me 262 (steering 9g and aileron 17g failure, OB, OG)
3@ SU35 (rudder 9g , stab 17G, OB)
3@ F5-E (Flap 9g, rudder 9g, OB, IF)
F14 (17g elevator 17g, IF (crash airframe loss, amp failure caught on video)
P51 1.4m ( Gear door 9g, IF [Crash BEC shut down from servo fire])
P38 (aileron 9g, OG (Servo fire, amp failure)
The Me 262 and SU 35 are from the earlier servo OEM, I think these were also analog.
Not to sound too negative I've had a few Freewing with no servo failures; two 64mm Stingers, One Mirage 2000 and one of those SU35. Also the best flying Foam EDF I've seen is the FW 80mm T33.
Full disclosure: MotionRC is so pissed with me (Customer service and engineering issues) that they will not sell to me. No real loss on my part.
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Scott Page
Very Strong User
I've got over 100 flights on my Avanti without any servo issues. I did, however have the plywoood battery tray snap fore and aft ejecting the battery during a high G snap and tumble.
