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Old 01-12-2022, 08:03 PM
49erMike 49erMike is offline
Join Date: May 2021
Location: Los Gatos, California (Near San Jose)
Posts: 7
Default RV-8 Garmin Autopilot Install Complete

Apologies for the tardy update on this, but our Garmin autopilot is now installed, calibrated, and flight tested. We are very happy with it. Our RV-8 already had a Garmin 430W and legacy (non touch) GDU 375 PFD/MFD, which made the install easier. We purchased two GSA 28 servos, a GMC 507 Control Unit, and RV-8 servo mounting kits for the pitch and roll servos from Garmin. Installation went quite smoothly; the roll servo mount kit is basically a bolt-on replacement for the existing aileron bellcrank mount. The installation of the pitch servo mount is more involved, as it requires drilling out 10 rivets to remove the old bellcrank brackets, match drilling the rivet holes into the new servo brackets, and riveting the new brackets into place. I was able to get a bucking bar underneath, which allowed me to drive rather than squeeze the rivets. For a number of reasons (not the least of which is we have Nik Nickravesh and his crew at Nice Air on our home field at KRHV in San Jose), we decided to let them do the wiring and that worked out well. We have the Ray Allen electric pitch trim, which is fully compatible, so the autopilot will automatically re-trim during climbs, descents, power changes, etc., and we also installed autopilot disconnect and TOGA (take-off / go-around) buttons on the control stick. We found several glitches in the Garmin documentation, but phone support from the Garmin experimental folks was top notch. The system performs better than expected, and we had pretty high expectations going in. It holds altitude in cruise WAY better than me, with minimal altitude loss rolling into turns and gain when rolling out of turns (typically 30-40 feet), which are quickly recovered. It is rock solid on approaches, including vertical descents on LPV and ILS approaches. Total hardware expenditure was $3,300 for the control unit, two servos and servo mounting kits, electrical connector kits for servos and control unit, tax, and shipping. I am happy to answer any questions and have photos I can share with anyone interested in this upgrade.
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