Originally Posted by BigTradioman
I have a question regarding RTL and throttle action.
I recently had a situation where I lost video down link due to an as yet diagnosed problem when flying at around 100m above launch height downwind during a trimming flight. The joysticks had not been calibrated.
I manually switched to RTL and the model did not return. Luckily a walker heard the props spinning up and shutting down and located the model intact laying in a hedge and having played the video recognized the take off location and returned the model about 2 hours later. How lucky am I!!
(We where flying sorties with another FPV model over the last known area that my spotter saw the model go down within 30 minutes but could not see the lost plane. Obviously because it had been recovered by then as the recovered video shows)
Unfortunately there is no OSD overlay on the on board video, but the recording clearly shows the moment when RTL command turns the model to the left at 1:46. Home can be seen on the nose of the model at 1:53, which is directly into wind. The model appears to slow down and then begins to lose altitude and drifts off line and makes a turn to the left and comes back on home direction by turning to the right getting lower all the time. At 2:58 a turn to the left is completed and the model is again heading directly towards home. The model turns down wind and lands safely at the base of the hedge.
At what altitude does the AP stop the motors so therefore prevents the model from climbing to the programmed RTL height?
As I had not completed the Joystick calibration is that why the AP failed to throttle up and climb to safe height?
Is this a known issue if the model is lower than launch height?
to my perception RTH only kicked in at 3:18 and started to climb then at 3.27 started to descend to safe altitude, or just wanted to maintain safe altitude but because of few factors(down wind, low cruise speed, trims) wan't able to maintain it and were loosing the altitude.
Until then only manual control was involved (maybe in stabilization mode).