Auto trim considerations

[cmarbach]

I am worried about turning over to Skyview automatic trim. What if it runs away and erroneously trims either up or down way too much? Can it be turned off by unpowering the autopilot and then manually (electrically in my plane) re-trimming?

Would I have to power off the autopilot (instead of just of just not using it) while landing? Does the autotrim only function while the autopilot is engaged.

 

[dynonsupport]

Auto trim can only function when the AP is engaged. It uses the servos flying the airplane to decide if it needs up or down trim just like you do from stick pressure when hand flying. There's no way to do auto trim without an AP- how would the system know that you wanted to fly level vs up or down? If it just always trimmed out the stick force you'd have a plane with zero stick force per G, which would be very, very dangerous.

So, when the AP is off, auto trim is off too. A simple disconnect of the AP will shut it down. You don't even need to turn off the servo power, but that works too.

It has various protections as well, such as timeouts. If it tries to trim constantly for a few seconds, the trim controller (totally independent of the AP) starts rejecting the trim inputs. The stick buttons also override the AP commands for trim.

In the end, it's both simple and robust, and we have yet to hear of any issues with it, but the protections are there.

 

[cmarbach]

But it is optional, right? If we don't install the trim part the system will function as before but with a control head we installed.

 

[dynonsupport]

Auto-Trim is optional. If you don't have the AP control panel, you can't have it. If you have the AP panel, you can choose to not wire up the manual trim controller in it, and if you have it wired to the AP control panel, you can disable auto-trim in the SkyView setup.