Tuning a few FBW params

So I’ve had a few flights with my Skywalker and after successfully ‘auto-tuning’ it I have had several more flights worth of logs to analyse and begin looking at tuning some other settings. Basic functions like RTL and LOITER work great, even in stiff breezes.

So right now, I’m looking at a few other params in conjunction with my logs, namely…


TRIM_ARSPD_CM (1200 cm/s)

THR_MAX (80%)
THR_MIN (0%)

It seems that TRIM_ARSPD_CM and TRIM_THROTTLE are balanced pretty well, the logs show about 12-14 m/s. Question tho, which of these two take priority, so if for example the throttle is at TRIM_THROTTLE (45%) but the airspeed is not at TRIM_ARSPD_CM, what does it do, ignore it or adjust the throttle accordingly?

I may have answered that one myself since the logs show a variable airspeed around the TRIM_ARSPD_CM param but a fixed TRIM_THROTTLE.

Second question, the logs suggest my ARSPD_FBW_MAX is set too high. When running at THR_MAX (80%) it is more like 18m/s. I will adjust it, but is it important and what would the affect be of an incorrect value for ARSPD_FBW_MAX?

Final question! What is the relationship between ARSPD_FBW_MIN and THR_MIN? I’ve assumed THR_MIN should be set to zero if I intend to venture into auto-landings, but the notes say that the minimum value for ARSPD_FBW_MIN is 5m/s where as I would have expected it to be set to zero. What I have missed?

Hope I haven’t asked too much!


Your THR_MIN is much too low. This needs to be about 20%-30% above the stall speed. I’m using 10 m/s on my 1900.