Our new Trio Pro autopilot has ‘auto-trim’, so in addition to wiring it up to power, ground, and the servos the pitch servo has an output to the pitch trim actuator There are a couple of different ways for this to interact with the pilot, either you can install a dual pole dual throw switch to select manual or autotrim (which I didn’t want to do, and seemed like a bad idea), or you can install a bridge rectifier and a relay that will normally allow autotrim, but energize the relay and pull the normally open contacts to when you activate manual trim. This is a very slick way to handle it, and so I grabbed a project box and some Radio Shack bits and got to work.

Autotrim defeat circuit

Autotrim box constructed

Autotrim box installed

Posted By: Brett Ferrell
Friday April 23rd, 2010 at 3:59 PM

Categories: AutoPilot Avionics GRT Hx EFIS
Tags: Autopilot Building GRT Trio

One response to “Trio AutoTrim”

  1. Document says:

    […] talk to the Horizon EFIS, but I think we’ll get that squared away shortly. I even have the AutoTrim cicuit working (Elizabeth likes to call it MagicTrim!). Meanwhile we’re starting the […]

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