ag0n
Captain
Flight distance : 700846 ft
United States
Offline
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"1) one method to stop the motors is pushing throttle to full down for more than 3 seconds; just to be sure, the bird will stop the motors only if it detected it's on the ground, in other words, when flying I can ask for a full throttle down to descend as quick as possible without fearing motors stop?"
Almost. It does not have to be on the ground, if I understand correctly. Vertical MOTION needs to cease for it to kill the motors with the left stick all the way back. I do not know if horizontal motion has to cease or not, but I would hope so. I still don't have the guts to pull it all the way back while descending, but would give it a try in a real emergency
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"3) what's the right way to get back control and abort RTH, in order that I can land safely on a small landing field?"
Press and hold the RTH button a second time to disable it (you can also do it in the DJI Go app). I don't know if flipping the PAF switch back and forth once will do it or not, but it might.
"4) is it necessary turning on the bird on a flat surface (for sensors calibration purpose) or can I turn on it on an uneven surface (still the issue of the local mountains)?"
I prefer doing compass calibration over my head at arms length to be sure it isn't near any metal buried in the cement or ground under the P3. As for IMU/gimbal calibration, YES, it needs to be very level and very solid so it doesn't pick up any vibrations while being calibrated. That calibration will be telling the control system that where you calibrated it is level and that will be its reference from that time until it is done again. If you calibrated it on a non-level surface, it will likely not fly correctly. In case you haven't read about it elsewhere, you should do an IMU calibration with a cold P3. The colder the better (above freezing). It will speed up the time that the P3 is "warming up" while you wait for green light to fly. After doing a cold calibration, my "warmup" time went from 2-3 minutes to about 15-20 seconds from time of turn on. |
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