Thanks for the tips! One of my goals is to figure out the stall speed of my Ranger EX QuadPlane. It must be higher than the stock version of the plane with the added weight and drag. Below are my default param settings for airspeed with my analog sensor. I have little understanding of them. I can blow into my pitot tube and see the airspeed value go up to 20 or 30 m/s so it appears to be working. The default ARSPD_RATIO of 2 is supposed to be good for most setups. I did not calibrate my ARSPD_OFFSET yet but I did make a foam cover for the pitot tube.
I changed the default setting for Q_ASSIST_SPEED from 10 to 12m/s as a precaution against stalls. This may keep the quad rotors on excessively so I am not sure it is good or needed until I try it. We use m.p.h here in the states so it seems that 1m/s is about 2mph.
I created an image below of GPS speed and my telemetry flight path with wind direction. The stall is around line 114 where the speed drops. If we assume 16mph wind (or 8m/s) then the plane speed was (GPS speed - wind speed) or 17 - 8 or approximately 9m/s. This rough estimation seems like the default Q_ASSIST_SPEED of 10 would still work as long as you install an air speed sensor.