Troubleshooting Auto-Pilot Issues

[lrobichaux]

I’m in the process of troubleshooting autopilot drift, jerkiness and overall unsatisfactory performance smoothly holding course, altitude and glide path. This morning I noticed that the G3X shows that there is no software installed on the pitch and roll controls. Have no clue if this is normal, or if it’s an oversight at CubCrafters. Any thoughts or suggestions would be appreciated.

 

[Cactus Charlie]

The blank entries for roll and pitch usually mean the servo switch was off. Servos must be powered for their status to be read.

With avionics bus on, then servos on, the PFD mode annunciator should show briefly PFT (pre-fight) which is the servo test before AP engagement is allowed.

It would not be possible to have AP engagement if no software was loaded in the servos. Servo software is updated with each G3X software update as long as the servos are powered.

 

[lrobichaux]

That’s the answer. Appreciate it.

 

[Cactus Charlie]

The autopilot performance questions were not answered. However, a couple of points-

Procedures for tuning the autopilot are included in the G3X Touch installation manual. All these adjustments are available in experimental aircraft but are likely only available to the system installer in a type certificated aircraft.

In turbulent air a Carbon Cub is not going to fly like a Cirrus which has a higher wing loading and much higher cruise speed. The first test of AP performance should perhaps be to compare what it does with what the pilot would have to do in the same conditions. (In my FX-3 the stick roll activity in turbulent air was far greater than when I was hand flying. I reduced the roll gain.)

 

[Neal]

@lrobichaux while flying or on the ground, and you don't have to be on the config side, you can adjust your roll and pitch rates. I can't remember what mine are set to but I had to adjust them. You can control the aggressiveness of the responses. That's probably the first step to adjust.