MGL Avionics User Forum

Hi All,

I am looking for some help in with my Jabiru 430 autopilot setting, its driven by my Voyager EFIS with Trio Gold Servo for both the roll and pitch. If someone can help with these EFIS settings I would be very grateful.

Further to my autopilot problem, I contacted Jake here in Australia from Trio, I leant they had found that some Slip Clutch torque nuts had machine marks on the flat surface of the nut and at times this has allow the torque nut to slowly undo allowing the servo Slip Clutch to loose its torque.

I found in my pitch servo the Slip Clutch nut had loosened off badly. So when I engaged the autopilot the pitch servo would start slipping straight away, this slippage made the EFIS think I was trying to over ride the autopilot and the EFIS would disengage the autopilot nearly immediately.

So after tightening up the slip clutch torque nut as far as I could, the pitch servo was still slipping with a lot less pulling pressure than the roll servo. So I purchased a digital fisherman's scale to check the pulling force needed to make the clutch slip in both the roll and pitch servo.

So with the scale hooked into the outer hole of the servo arm, the pitch servo clutch only took 2.9 to 3.1 Kgs of pull pressure to make the clutch slip, the roll servo clutch took 11 Kg of pull pressure to make its slip.

Here was the problem shown in the pic, the gold disc next to the torque nut was not been seated properly on the shafts keyway so would not sit correctly in the white clutch drum.
It should look like this once the disc is seated on the shafts keyway properly and then the torque nut can be tighten up further pushing the gold disc into the white clutch drum.

So if you have got this problem and want to get the gold disc back into the drum and on its keyway. Well it took a number of goes and lots of patience as you are doing this blind, you see very little in the clutch before you start the nut and you need an electronic microscope to workout where the flat side of the keyway is and then once you start the nut you will see nothing.

It's all by feel and step tightening the torque nut and pushing the disc around until you feel it move onto the keyway and stops moving around. Really if I was in the States and did not have the exchange rate, postage cost and shipping time frames. I would say for most people, put the servo in the post and send to Trio, Chuck in the USA or for us Aussies, Jake in Australia.

How did this happen, well I really don't know in my situation. But it could be very easy for someone to undo their torque nut just to far and this allows the gold disc to slip off the internal keyway. The first you realize this has happened is when the gold disc will not go back into the white Clutch drum as you tighten this torque nut.


Cheers
JimJab

Hi All,

You may see I have re-edited and changed my first post to be more about fixing the slip clutch in my Trio Gold pitch servo. I realize its not about MGL stuff, but I hope it helps someone with some background information in the Exp world.

Also I am really looking for some help in cross checking my MGL EFIS /Trio autopilot setting for a Jabiru 230/430. If someone can help I would be very grateful.

So after fixing my pitch servo slip clutch, we re-installing and ground testing everything, from over centering, operating in the right direction and disengaging with Joystick control input, via the servos slipping.

Off for a short flight with great anticipation, I trimmed the Jab for level flight and engage the autopilot for straight and level flight. The aircraft remained level in flight, but the pitch servo push the aircraft into a decent. I pulled back on the joystick and pitch servo slipped and the autopilot disengaged. So I engaged the autopilot again and the same thing happened.

I don't know much about setting up autopilot servos, but it seemed to me that the pitch servo might think it's elevator position for level flight may not be where it is.

When I got back to the airstrip, I took the push/pull cable off the pitch servo and using the EFIS's autopilot test mode set the pitch servo to it's center position and then put the elevator roughly in my level flight position. I took a pic of the push/pull cable and the servo crank arm position. I was thinking these position should nearly be aligned.


So Am I wrong in thinking this, any help would be really appreciated ?????????


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So over the past few day I have been working with Jake the Trio Dealer here in Australia.

I was thinking I might need to re-align my servo center position to align with my elevator push/pull cable position for level flight.

Well, as it has turn out it's not as critical as I thought, but it seems better if you do align every thing at the time of installing the servo if you can.

So thanks to Jake, I now have an autopilot functioning with my MGL Voyager and not try to dis-engage all the time.

So the next step is to see if I can make my plane and autopilot fly nicely together by adjusting the Voyager EFIS settings.

I'll keep you posted and see what setting I end up with, anyone offering up their setting for their Jabiru 230/430 that would be a helpful.

Cheers
JimJab