Hi, Ardupilot 2.6 (still with thermopiles) did a pretty good job in handling our solar drone (seriously, http://diydrones.com/forum/topics/lusa-low-cost-unmanned-solar?id=705844%3ATopic%3A445243&page=2#comments), now we bought APM2.0 to improve the results thanks to the ultra-precise IMU and other things such as the built in compass that can help controlling such a weird-handling plane like t…