Experimental G5 w/GAD29B + SL30 + STEC-30

My aircraft is currently equipped with a mechanical HSI, electric AI, a SL-30 and an S-TEC System-30.

I am looking to remove the mechanical HSI and AI install a dual G5 system with a GMU-11 and a GAD29B.

A couple of questions:
- Is the experimental G5 software capable of interfacing with the autopilot outputs on the GAD29B?

- The G5 appears to mimic a "GPSS" unit when outputting an analog heading error signal on the GAD29B autopilot interface. This would seem to enable the G5 to drive an analog autopilot (when in heading mode) with the heading bug on the G5. Correct?

-Does/can the G5 w/GAD29B also mimic a GPSS unit and drive the autopilot outputs on the GAD29B with "derived" digital SL-30 course error data received via the G5 serial interface? I assume received -429 data sent by a GTN/GNS GPS over the GAD29B -429 interface would be "translated" to a GPSS type heading error signal.. but how about plain old NMEA type data ?

What would happen if one installed THREE G5 units on a single CAN bus with one GMU-11 attached?

I think it will do all you are askin, but I think you would be much happier and much more feature rich if you installed a Garmin auto pilot with a GMC307 controller. The Stec should be worth something, but the Garmin auto pilot would only cost about $3,000. If you out in 3 G5?s, I would make one completely independent, not tied to anything.

Since your airplane is not an EAB, I?d start by contacting Garmin to make sure the necessary paperwork exists for an sf260.

Some of those SF260s (the luckier ones) are registered as Experimental Exhibition category.

"Since your airplane is not an EAB.."

The Marchetti is in the "Experimental Exhibition" category. The red-headed stepchild of EAB.


Anyway - I also emailed Garmin directly and the response I received indicated:
1) Version 4.1 of the experimental software supports analog outputs on the GAD29B
2) Three G5s on one CAN bus is not supported (this I assumed due to a one bit unit address strap)
3) GPSS translated to analog out is supported for -429 inputs on the GAD29B .. however I did not receive a good answer about serial NMEA into the G5 translating to analog heading error out on the GAD29B. I think this is unlikely but would be very nice to have -- i.e. having an Aera 660 steering a S-Tec autopilot via NMEA.
In G5 heading mode, the G5 heading bug can be used to steer an analog autopilot (in heading mode) via heading error output. This is how a GPSS box works.

I personally would just go the 307 with garmin servos route. I replaced my stec 50 with it and don?t regret it one bit. However, the bad news is I don?t think the stec is worth anything. I?ve tried giving away my whole stec system including DG and artificial horizon and all as most guys want it for certified. Stec is doing a great job of pricing themselves out of the autopilot market. They wanted $13k to ?refurbish? my system or would sell a whole new one for $15k.