[October 1, 2022]

It's time for some avionics upgrades! Currently I run a Grand Rapids autopilot which is controller from my GRT EFIS. It has worked flawlessly! However, the more IFR flying I do, I was a little more capable autopilot, along with an autopilot who's functionality is divorced from my PFD. For example, if I were to lose the PFD, I would loose the AP, attitude/airspeed/altitude (those backed up by the Garmin G5) - so a lot. There is also a lot of button pushing with the GRT autopilot to get it to do what I need it to.

I have heard nothing but great things about the Garmin AP. So let's see if it's all true or not!

First step is the most painful - taking out a bazillion screws for the inspection panels.

I already have a G5 which acts as the main brains of the autopilot. I bought (2) GSA 28 autopilot servos, (1) GMC 507 autopilot control panel, a GMU 11 magnetometer and a GAD 29 to interface ARINC into the system. The Garmin part numbers are like learning another language!

Their GSA 28 servo is REALLY REALLY nice. Super lightweight. The servo arm has essentially no resistance.

There are some slight physical differences between the servos. The GRT servo (LEFT) has a much wider mounting plate that is tapped for 10-32 bolts. The Garmin is much skinnier and isn't tapped.

The bracket that attached to the top of the servo will also need to be modified to adapt to the GSA 28. Garmin does sell an installation kit for the RV-7 aileron (p/n 011-02952-12) but I am not about to spend $100 for just one bracket!

I have a good amount of wires already in place for the servos, but I needed to add a shielded pair of wires for the CAN bus (Stein air Shielded Wire, 22 Ga. 2 Conductor). My planned route is from the panel to the roll servo, back into the fuselage and then to the pitch servo, and finally terminating at the GMU 11 magnetometer. I needed to add power wires for the GMU 11 - 22 AWG black and red wire pictured here.

Amazingly enough the wire pulls were quite easy. So happy I put in all the conduit I did at build time!



Last Modified: August 13, 2023