SERVO NOISE.

[ZK-LCM]

My just fished RV-6 is fitted with a D100 EFIS, D120 EMS, AP74, with Roll & Pitch servos. It also has a Dynon heated Pitot-AOA.

Today on the ground I carried out AP Setup step-2 SERVO CALIBRATION & SERVO TEST per the Instn Manual Page 6-15.

Initially I experienced problems with slipping & found that BOTH servos had their Torque values set way too low. I increased them both to 50%, & the Servos then drove the controls to the necessary extremes. May I suggest that the effect of Torque values need to be mentioned prior to STEP 2b, not after it in the next step.
Would also be useful to mention the "chattering" noise that can occur if the Torque is set too low.

However, after the control movement I noticed a low volume "Whirring-like" noise coming from the Roll Servo, but not the Pitch Servo.
When I cancelled the Test tis noise ceased completely. Is this low volume "noise" a reason for concern? It only occurs at the end of Step 2 and whilst "SERVO TEST" is still selected.

Anybody else experienced this. The noise level is about the same as running tap water at low flow.

Thanks.
Graham
New Zealand.

 

[airguy]

For what it's worth, I keep my servo torque set at 100%. The whirring or buzzing noise you refer to is the servo stepper motor holding position and is normal. If you had your ear right next to the servo in flight you would hear it then too - but there is too much ambient noise.