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  #1  
Old 01-01-2016, 09:13 AM
Guilhermepilot's Avatar
Guilhermepilot Guilhermepilot is offline
 
Join Date: Jan 2013
Location: brazil
Posts: 316
Default G3X autotrim problem

Hello capt's
My set up is single screen G3X with two garmin servos, pitch and roll, also have a alley electric trim, for some reason, my auto trim never worked (40 hrs by today)
The problems is

At level flight after a couple of minutes, the trim overrun pitch down until a press to dsc. I am flying with auto trim disable. And making corrections as needed via trim button
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Guilherme Plassmann (Brazil)
RV7A (Mr Flame) slow kit S/N 74285 Finished 04/14/15😀😀😀😀flying
G3X
Superior IO360
Sterba prop
TSFlightlines hoses
LR30,PRM1,C560,C510S,HS125,B350 FAA/ANAC Pilot

Donation made 2016

Last edited by Guilhermepilot : 01-01-2016 at 09:17 AM.
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  #2  
Old 01-01-2016, 09:41 AM
brooksrv6 brooksrv6 is offline
 
Join Date: Sep 2009
Location: Port Orange, FL
Posts: 34
Default

Have you verified in configuration that the trim is
running in the correct direction?
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  #3  
Old 01-01-2016, 11:34 AM
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g3xpert g3xpert is offline
 
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Location: Olathe, KS
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Quote:
Originally Posted by Guilhermepilot View Post
Hello capt's
My set up is single screen G3X with two garmin servos, pitch and roll, also have a alley electric trim, for some reason, my auto trim never worked (40 hrs by today)
The problems is

At level flight after a couple of minutes, the trim overrun pitch down until a press to dsc. I am flying with auto trim disable. And making corrections as needed via trim button
Hello Guilherme,

We have to agree with Chris that perhaps your pitch trim motor is running in reverse when the autopilot is engaged and auto-trim is enabled.

First, a description of the trim architecture in your aircraft. There are three ways that trim operates.

Servos Powered Down (backup trim mode)
In this dirt simple backup mode a relay closes inside the GSA 28 servo and passes the trim motor wires directly through the servo. The wires connected to input pins 11,12 at the servo are directly connected to output pins 13,14.
Servos Powered Up, Autopilot Disengaged
This is the normal mode of operation when the autopilot is disengaged. The trim control inputs on pins 11,12 of the servo are read by the servo microprocessor, and speed scheduling is added by the servo to automatically drive the trim motor and vary the speed of the trim motor (using Pulse Width Modulation) to match the speed scheduling configuration.
Servos Powered Up, Autopilot Engaged
This is the normal mode of operation when the autopilot is engaged. It is very similar to the previous mode except that the servo ignores the inputs and drives the trim motor based on out-of-trim torque sensing that it does on its own.
Here is a simplified version of the steps explained in the G3X Installation Manual to configure/test your trim installation.
  1. Power off the servos.
  2. Use aircraft trim switches to run the trim motor. If the trim motor runs in the wrong direction, swap the trim motor wires at the control stick, at the servo on pins 11,12 (switch inputs), at the servo on pins 13,14 (trim motor drive wires), or at the trim motor itself.
  3. Verify that the trim now runs in the correct direction with the servos powered off.
  4. Apply power to the servos.
  5. Use the on screen controls on the servo configuration page to drive the trim motor for that servo.
  6. If trim motor runs in the wrong direction, change the trim motor direction setting on that page from Normal to Reverse (or Reverse to Normal if it is presently Reversed).
  7. Re-verify that the trim operates correctly in both the servo powered on and servo powered off conditions.

Let us know if you have questions.

Thanks,
Steve
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Last edited by g3xpert : 01-02-2016 at 12:09 PM. Reason: Improve guidance.
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  #4  
Old 01-01-2016, 12:29 PM
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Guilhermepilot Guilhermepilot is offline
 
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Location: brazil
Posts: 316
Default

Allright

I will do that

I thought It would be ok since the direction
On my stick is correct

Many thanks guys
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Guilherme Plassmann (Brazil)
RV7A (Mr Flame) slow kit S/N 74285 Finished 04/14/15😀😀😀😀flying
G3X
Superior IO360
Sterba prop
TSFlightlines hoses
LR30,PRM1,C560,C510S,HS125,B350 FAA/ANAC Pilot

Donation made 2016
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  #5  
Old 01-03-2016, 02:41 PM
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Guilhermepilot Guilhermepilot is offline
 
Join Date: Jan 2013
Location: brazil
Posts: 316
Talking

Trim motor in inverted mode solved, now, ap on and hands free!

Thanks
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Guilherme Plassmann (Brazil)
RV7A (Mr Flame) slow kit S/N 74285 Finished 04/14/15😀😀😀😀flying
G3X
Superior IO360
Sterba prop
TSFlightlines hoses
LR30,PRM1,C560,C510S,HS125,B350 FAA/ANAC Pilot

Donation made 2016
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