SonexBuilders.net

I am in the process of installing a TruTrak Vizion autopilot in my legacy Sonex.

The control unit sets-up includes a feature to set aircraft specific parameter. The autopilot manual lists recommendations in the appendix for a number of aircraft (RV etc.) but not for a Sonex. If someone out there has already done the same installation, I would appreciated the sharing of flight test confirmed parameter settings. The categories are as follows:

Lat Activity -
Bank Angle -
Microactivity -
GPSS Gain -
Vrt Activity -
Min Airspeed -
Max Airspeed-
Static Lag -
Microactivity -
Half Step -

Thanks for any help.

Well, I have just installed one and I tried the setup suggested for the RV4 but it does not seem satisfactory. Mine seems to work well in the simple bank mode, not connected to a GPS, but when I connect it to either my MGL Xtreme or my IFLY740, it wants to hunt and be unstable in any turbulence at all. This is in both pitch and roll. I have tried very low Lateral settings and very high ones, same with vertical activity settings. It just hunts either aggressively or less aggressively, but is not stable Going to call TruTrak tomorrow and ask about it. There is ZERO lost motion in my control system so that is not the problem.
Sonex 1212, Corvair 150mph TAS at cruise 75% power

Just made a tuning flight today and got it worked out. I had some light turbulence this morning and took advantage to sort out the hunting that showed up once I had some turbulence. I wound up with a lateral activity setting of 12 and a vertical activity setting of 3 with the half step feature turned on. Part of the vertical instability I was having was that the pitch control is very light on my airplane and the normal full step was too much pitch down or too much pitch up with the arm lengths you have to use on the Sonex. The half step fixed this. The lateral stability at the Van's RV settings is just too low and hunting is the result. I went all the way to 17 and the roll control got jittery. I backed it off to 14 and it was pretty good, but I am happier with 12 for the setting.
Ed