[maus92]

Is anyone flying a G3X system w/ GSA 28 servos and the VP-X Pro and successfully using Garmin's auto trim function? . I'm trying to determine the correct configuration for the VP-X Pro to allow the G3X system to provide auto trim. The VP-X documentation is a bit vague on the subject, although I have wired the trim motors according to section 5.19g. The confusing part is how to configure the trim functions in the VP-X to allow the Garmin to control auto trim functions - I've set the speed to 0 on the pitch trim page, but there are other parameters, and on the roll trim page, there is no speed setting. I had an inconclusive convo with CJ from VP - both of us were not in front of either the hardware or documentation, and his suggestion to wire the trim system outside of the VP-X doesn't sound correct (at least it's something that I don't want to hear...

 

[Brantel]

I use the G3X Touch along with the Garmin AP and servos and the VPX Pro.

Works great! The Garmin servo gets wired in between the VPX and the trim servo.

Turn off the airspeed controlled trim speed function of the VPX is all you need to do on the pitch servo. The roll trim part of the VPX does not have this function that I recall.

 

[SMO]

Turn off the airspeed controlled trim speed function of the VPX is all you need to do on the pitch servo.

Interesting - I have a VP-200 and was using the Trutrak AP with autotrim and left the airspeed controlled trim speed function on - it worked just fine. Plan on going to a Garmin Touch and AP, expecting it to work the same, but..............

 

[g3xpert]

Hello maus92,

We have numerous users enjoying their G3X systems using the GSA 28 autopilot servo in conjunction with the VP-X. As usual, Brian is correct - the pilot and copilot trim switches connect to the VP-X, the VP-X connects to the trim inputs on the GSA 28 servo, and the GSA 28 trim outputs connect to the trim motor.

You will want to refer to the lower half of Figure 21-1.7 in the G3X installation manual, which shows this type of installation. In this use case, the VP-X only provides the function of mixing the pilot and copilot trim switches; all speed control is done by the GSA 28 servo. Note the guidance in this drawing to "disable speed control if equipped" on the third-party trim mixing device, which in your case would be the VP-X.

- Matt

 

[Brantel]

Interesting - I have a VP-200 and was using the Trutrak AP with autotrim and left the airspeed controlled trim speed function on - it worked just fine. Plan on going to a Garmin Touch and AP, expecting it to work the same, but..............

The reason to turn off the airspeed controlled trim speed is because that function may interfere with the G3X since it also can control trim speed. The TT AP does not as far as I know so it would not hurt you to leave it enabled with that setup.