Any good nuke submariner knows that if you take a 50/50 shot you will get it wrong 90 percent of the time; and so it is with roll trim. I'm trying to improve my odds:
I'm installing the roll trim kit in my 14, with the wings still on the stand. No roll servo in yet, but soon/later. The plans say to just wire up the servo; no problem if it is backwards later we can just switch wires. But it isn't just a simple switch system. In the G3x system a stick switch drives the GAD27, and that drives a trim line (by relay in the GAD27), on to the roll servo, and then to the trim motor.
So one feature of this is that the roll servo will trim the ailerons to reduce torque on the roll servo, automatically. Thus make it live longer, use less power, all that good stuff. But how does it know which way to go? How would I know if the line is backward later between the roll servo and the trim motor? Does it even work if the wiring is backwards?
For that matter, how do you know what is up and what is down at the GAD27 to connect to the roll servo correctly.
Looking at the G3X Install manual (Rev AB here) on page 25-3, we find that the GAD27 J272 pins 9 and 10 have that function out to the roll servo "left or right". Is pin 9 "left"? Lets say we connect it to pin 11/12 on the roll servo J281, and it outputs to J281 pins 13/14. Then output pin 13 should be left? And I would make sure that wires to the trim motor in such a way that hot out of 13 turns the plane left?
Taking that one more step, at the trim motor connector, pins 4 and 5 are the pins for the motor drive. Pin 5 on the trim motor connector maps to pin 13 on the servo output using the supplied wing harness. So in the end it seems I should set up the wires on the trim motor so hot 5 and ground 4 moves the trim to turn the plane left.
Plane turns left when right aileron is down. This is when the aileron push tube moves toward the tip and away from the fuse. So it would seem that I need to figure out which wire is hot when the lever on the trim motor moves to the tip, and get that into the connector on position 5 of the trim motor connector...... so it is on pin 13 of the roll servo trim output.....
But all that assumes that on the GAD27 J272, pin 9 at 12V and pin 10 at gnd is intended to turn the plane more left. Is that true? Did I mess anything else up in this analysis?
I'm installing the roll trim kit in my 14, with the wings still on the stand. No roll servo in yet, but soon/later. The plans say to just wire up the servo; no problem if it is backwards later we can just switch wires. But it isn't just a simple switch system. In the G3x system a stick switch drives the GAD27, and that drives a trim line (by relay in the GAD27), on to the roll servo, and then to the trim motor.
So one feature of this is that the roll servo will trim the ailerons to reduce torque on the roll servo, automatically. Thus make it live longer, use less power, all that good stuff. But how does it know which way to go? How would I know if the line is backward later between the roll servo and the trim motor? Does it even work if the wiring is backwards?
For that matter, how do you know what is up and what is down at the GAD27 to connect to the roll servo correctly.
Looking at the G3X Install manual (Rev AB here) on page 25-3, we find that the GAD27 J272 pins 9 and 10 have that function out to the roll servo "left or right". Is pin 9 "left"? Lets say we connect it to pin 11/12 on the roll servo J281, and it outputs to J281 pins 13/14. Then output pin 13 should be left? And I would make sure that wires to the trim motor in such a way that hot out of 13 turns the plane left?
Taking that one more step, at the trim motor connector, pins 4 and 5 are the pins for the motor drive. Pin 5 on the trim motor connector maps to pin 13 on the servo output using the supplied wing harness. So in the end it seems I should set up the wires on the trim motor so hot 5 and ground 4 moves the trim to turn the plane left.
Plane turns left when right aileron is down. This is when the aileron push tube moves toward the tip and away from the fuse. So it would seem that I need to figure out which wire is hot when the lever on the trim motor moves to the tip, and get that into the connector on position 5 of the trim motor connector...... so it is on pin 13 of the roll servo trim output.....
But all that assumes that on the GAD27 J272, pin 9 at 12V and pin 10 at gnd is intended to turn the plane more left. Is that true? Did I mess anything else up in this analysis?