Servo Problems.

[David Barker 2]

Hi I have found a problem with all servos still moving after moving sticks on transmitter. This only happens for a few seconds. The receiver is a Spektrum 6210 Satellite. And Ripmax Quartz metal geared servos. Power from 5 cell AA 6.0 v battery. The receiver specifications say upto 9.6 volt can be used and servos upto 6.0v.Is this a start of a problem with the receiver, as I don't have a second one to test in place of original. Thanks Dave.

[Denis Watkins]

Some servos Dave are designed "slow moving", and would return to zero after the sticks, also the TX may be set to "servo slow"

These are just 2 ideas

[Martin Harris - Moderator]

I think these will be metal geared digital servos which often exhibit this behaviour, particularly with unbalanced control surfaces or substantial control links - the momentum carries the surface fractionally beyond the desired position, the servo counters strongly (as is the nature of digital servos), it goes back fractionally too far etc. etc. until the amplitude decreases enough for the servo to settle.

I'm told that a common cure in some circles is to use a small piece of smooth Velcro attached to the edge of the cutout between it and the control surface to provide a damping effect.

Edited By Martin Harris on 01/08/2016 10:55:42

[Don Fry]

When you say still moving after moving sticks on transmitter I take it the servos are being slow following the stick commands. Or something else, for instance an oscillating movement?

[Martin Harris - Moderator]

Says flutter in the subtitle...

[Robert Hynes]

Hi Dave,

to be sure I understand this, I believe you are saying:

1. The RC installation works well with flying surfaces obeying transmitter commands correctly but......

2. After giving any Tx command and returning the controls to neutral, all axes, e.g. rudder, elevator, aileron, throttle, jitter or flutter, (rapid oscillatory movements of the servo output shaft), for a few seconds before settling down at their neutral positions.

If this fault description is correct, the issue electromagnetic noise, which is often seen with digital servos but rarely if ever with the earlier analoge types and is dealt with on RCAeroBase here: http://rcaerobase.ipjdev.co.uk/index.php/radio/radio-servos/87-control-surface-jitter-problem

The specific points being 7a, and/or 7b If you think this may be the issue, then a quick test would be to remove the digital servos and add a test analogue servo. If the jitter stops, then the test has identified the the digital servos as the noise source which is getting into the Rx input citcuitry and being falsely recognised as servo commands.

If the description is incorrect there are other solutions to other causes.