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- Jan 17, 2014
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Just experienced this which might be something to be aware of and keep in mind.
Although it was still fairly windy it was also fairly sunny and I wanted to see whether I could shoot some nice images from a higher level than I had done before and at the same time test whether it would still be within the FPV WiFi range of my FC40.
Previously I had increased the geofence ceiling in steps going from 30m to 50, 75 and 100m and had flown at those altitudes. I now had it set to 150m. During my first flight I noticed when I had gone to perhaps 50m that the Phantom was drifting downwind without stick input. I had to give forward stick to move against the wind. Apparently the autonomous manoeuvring speed wasn't high enough to compensate for the wind drift. I decided not to push it and descended again. It would seem that the wind gradient was stronger than I had experienced before.
Next battery I tested again at moderate height and this time it held position so I went higher up. I shortly tested drift in ATTI and also moved a bit upwind for extra margin and generally flew with more (prolonged) full forward stick than I probably had done before. Suddenly I noticed it was descending. I hadn't initiated that. Then I noticed a red flashing light so I concluded it was in L2 autoland mode. I was very surprised since I use a timer app that warns me every minute and also signals the 6 and 7 minute mark above which I keep it gradually closer. Between the 7 and 8 min. mark I usually begin to see red flashes. I couldn't imagine I would have somehow missed the signals and quickly checked the timer to see that it wasn't even close to the 6 min warning. I actively descended my Phantom and checked at low hover for a short period whether the red flashes would disappear again but they didn't so I quickly landed. Total flight time was about 5:50. Flight time after L2 autoland must at least have been 30 sec. That battery has given me flight times of around 8:30 with FC40 camera attached. After disconnect I checked the voltage and it was 11.4. Usually it is at 11.2-11.3 at home and shortly after the flight probably lower but since I don't push the limits I don't routinely check the voltage in the field.
I reconnected the battery and got green flashes. I decided to fly it again to see how much extra flight time I would get until L1 and the usual landing time. I flew another 3:10. Clearly the battery wasn't really empty the first flight.
My guess is that the fairly aggressive full forward stick use due to the strong wind caused the voltage to drop below the L2 autoland level. Fortunately it was perhaps only 15 m away from me horizontally but something like this might cause greater problems when flying further out and/or at lower altitude if you are caught by surprise still expecting several more minutes of uncomplicated flying time. I could see the red flashing pretty soon but at greater distance this won't be recognised as easily.
I am not at all sure the Phantom switches back from L2 autoland to L1 if the voltage rises again. Something I'd like to know. DJI should know this but I haven't read any info about this.
I'm now wondering whether I should set my L2 voltage a notch lower. I don't know how much less margin that would give me in real L2 autoland situations before the Phantom would drop uncontrollably.
This wasn't the original battery but a Hacker 2400 Topfuel. Have others experienced L2 autoland kicking in prematurely as a result of aggressive stick use?
And does anyone know whether the Phantom can/will revert to L1 warning level and will abort autoland when voltage rises again?
Although it was still fairly windy it was also fairly sunny and I wanted to see whether I could shoot some nice images from a higher level than I had done before and at the same time test whether it would still be within the FPV WiFi range of my FC40.
Previously I had increased the geofence ceiling in steps going from 30m to 50, 75 and 100m and had flown at those altitudes. I now had it set to 150m. During my first flight I noticed when I had gone to perhaps 50m that the Phantom was drifting downwind without stick input. I had to give forward stick to move against the wind. Apparently the autonomous manoeuvring speed wasn't high enough to compensate for the wind drift. I decided not to push it and descended again. It would seem that the wind gradient was stronger than I had experienced before.
Next battery I tested again at moderate height and this time it held position so I went higher up. I shortly tested drift in ATTI and also moved a bit upwind for extra margin and generally flew with more (prolonged) full forward stick than I probably had done before. Suddenly I noticed it was descending. I hadn't initiated that. Then I noticed a red flashing light so I concluded it was in L2 autoland mode. I was very surprised since I use a timer app that warns me every minute and also signals the 6 and 7 minute mark above which I keep it gradually closer. Between the 7 and 8 min. mark I usually begin to see red flashes. I couldn't imagine I would have somehow missed the signals and quickly checked the timer to see that it wasn't even close to the 6 min warning. I actively descended my Phantom and checked at low hover for a short period whether the red flashes would disappear again but they didn't so I quickly landed. Total flight time was about 5:50. Flight time after L2 autoland must at least have been 30 sec. That battery has given me flight times of around 8:30 with FC40 camera attached. After disconnect I checked the voltage and it was 11.4. Usually it is at 11.2-11.3 at home and shortly after the flight probably lower but since I don't push the limits I don't routinely check the voltage in the field.
I reconnected the battery and got green flashes. I decided to fly it again to see how much extra flight time I would get until L1 and the usual landing time. I flew another 3:10. Clearly the battery wasn't really empty the first flight.
My guess is that the fairly aggressive full forward stick use due to the strong wind caused the voltage to drop below the L2 autoland level. Fortunately it was perhaps only 15 m away from me horizontally but something like this might cause greater problems when flying further out and/or at lower altitude if you are caught by surprise still expecting several more minutes of uncomplicated flying time. I could see the red flashing pretty soon but at greater distance this won't be recognised as easily.
I am not at all sure the Phantom switches back from L2 autoland to L1 if the voltage rises again. Something I'd like to know. DJI should know this but I haven't read any info about this.
I'm now wondering whether I should set my L2 voltage a notch lower. I don't know how much less margin that would give me in real L2 autoland situations before the Phantom would drop uncontrollably.
This wasn't the original battery but a Hacker 2400 Topfuel. Have others experienced L2 autoland kicking in prematurely as a result of aggressive stick use?
And does anyone know whether the Phantom can/will revert to L1 warning level and will abort autoland when voltage rises again?