I’ve uploaded two bin files that may help in investigating the “sink” behaviors I’ve observed when in Loiter or Altitude Hold flight modes and transitioning horizontally.
The first BIN file is from a test flight across an open field at an altitude of about 2 to 3 meters. The vehicle is a Hexsoon EDU-450 with an Orange Cube. I don’t recall if it was running 4.1.0 or 4.1.1 at the time - it’s 4.1.1 now. This copter had been through setting the FFT filter, and AutoTune.
On this flight I transitioned away from me about 100 meters, and then returned back towards me. I increased thrust several times to recover lost altitude. On the return, the vehicle was far enough away from me that I couldn’t precisely see the actual height above the ground, and the landing legs struck the ground causing the copter to flip over. I engaged Emergency Motor Stop.
The second example is with my Hexsoon TD-650. This copter also has an Orange Cube, is running 4.1.1, and has been through setting the FFT filter. I haven’t yet completed AutoTune on this copter.
The BIN file is from a flight where I tested Loiter in the breezy conditions - and then tried AutoTune in Loiter. The copter did a good job holding position - but lost altitude during wind gusts and horizontal transitions. In AutoTune performed as described in the docs. I only stayed in AutoTune for a few minutes before initiating RTL.
This flight was in somewhat cooler conditions than previous flights. And it was windy. I don’t know if this is related, but the previous Hover Thrust was too low - and it took a few minutes for it to “learn” the proper setting for the conditions.
Analysis of these BIN files for problems related to Wind Speed Estimation and Barometer Interference Compensation is beyond my present abilities. Although I’ve charted the sampled barometric pressures and altitudes looking for clues.
I hope this helps in anyone’s investigation looking into this issue. Please let me know if I can help.