I ran into an issue earlier this year when a gusty day pushed my FX-61 (elevon flying wing) into a nosedive and fatal crash. Happily only the styrofoam was damaged, so I built a new one with the guts from that which crashed. I made a few flights with the new one, and decided to re-autotune in an effort to minimize sinusoidal altitude during mapping missions. It has been flying well, but today some gusty winds came in and I nearly faced an abrupt and catastrophic end to my field season. It's at a point where cutting throttle results in a stable drop, where the plane remains level but falls in elevation. It flies well in windless Auto mapping conditions,
Winds picked up and a surprise thunderstorm ended the day as it was, but erratic Auto flying led me to switch to RTL; it began pulling over 90-degree rolls and it looked like it belonged in a circus. Finally it stabilized and I was able to bring it in for a controlled landing.
Is there anything to look for in log files that would help minimize these unpredictable responses to gusty conditions? Obviously there is a maximum sustainable flight environment, but I'm hoping you might have some insight as to what went wrong (specifically, was this crazy flight a response to gusts, or was it the result of poor tuning, or what?). My CG is damn near the factory specs, and
Flight log available here.