I have one DJI Naza MRs (F450), and two DJI Wookong MRs (F550 and S800). I fly the F450 in very tight confines, including indoors. On one of my first MR flights ever, my F450 hit a tree branch and began to tumble to the ground. The Naza corrected the aircraft, leveled it off about 2 feet from...