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RV12is electric trim

M

montellopnds

Member
I am involved in a student build of an RV12is. We just powered the G3X up and made sure everything was working. The only thing not working was the electric stabilator trim. We are wondering if both lanes needs to be online in order for the trim to work.

Any help from you all is very much appreciated and thanks in advance.
 
Have you connected the servos up for the Autopilot yet?

If not, do so and try again. The signals to drive the stabilator trim go through the servos first.

John.
 
AFAIR there is a note in the PAP that with Garmin avionics and autopilot, the trim speed potentiometer on the back of the AV6000 needs to be turned all the way up for the avionics to recognise the trim command.
 
This happened to me. Your students are going to get some good lessons in reading wiring diagrams, making hypotheses, and testing them. I'd start by testing the trim controller circuits: does the motor run when power is supplied to the D-sub connector in the tail fairing? Does the connector there get power from the cockpit when the trim buttons are activated? Do you have continuity in the wires of the pitch trim circuit?

There are more tests following if those fail: the system is very complex, since it takes signals from the pitch autopilot, and you may have to test pins on the large D-sub connector that fits into the AV-60000 power controller. Eventually I found that the little Arduino nano computer integrating signals from the pitch servo and the joystick buttons needed replacement. Hopefully you will find some simpler fix.
 
Right then you will have to bypass the connectors on the servo system. Garmin sell a little D Sub connector that will do this for you or you can make your own.

Presumably you have the harness that is future proofed to accept an autopilot ie it has the wiring already there.

Give ma a day or two and I'll try to find out the pin connections for this, and or the Garmin part number. I have a email somewhere from Vans as I also had this issue.

John.
 
The included harness has all the wiring for autopilot if someone wants to install later. So if I understand…we need buy or fabricate a connector to bypass the servo system???
 
Check that the WH-P30-1 9-pin D-Sub connector is populated correctly. This is the 9-pin connector that is plugged in the back of the AV-60000 Power Module.

The "trim motor power wires" from the 5-conductor tailcone wire, which are either both white or could be black and white wires (not ORG, GRN or BLU) must be installed in pin 1 and 2 in the 9-pin connector when NOT using the autopilot. Refer to KAI 42MiS/U-12, Figure 2.

WH-P30-1 Trim Wiring.png

The trim speed potentiometer on the Power Module will affect the speed of the trim motor in this case. Refer to the PAP pages G1-1 & G1-3.

PAP Trim Speed.png

You do not need to fabricate a bypass connector.

Edited to add - You do not need the Lane switches on, they control the Rotax engine computers (ECU).
 
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From Eric at Vans

Sterling and I were discussing your dilemma, the missing plan instructions and alternative ways to solve it.



He came up with a good idea that would alleviate any pin changes if you (or a future buyer) ever decided to add autopilot servos. You could make a Dsub at the AP Pitch Servo connector back where it would plug in to the servo to jumper those wires. You’d jumper Trim In 1 to Trim Out 1 and Trim In 2 to Trim Out 2. If you want to add the AP Servos down the road, you’d just remove that jumper Dsub and plug in the pitch servo Dsub.



1739001394425.png


Or buy Garmin part No 011 03158 00 Which does the same.


John.
 
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