djiuser_L993ni8
lvl.2
Flight distance : 2808 ft
France
Offline
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ok, here's the update. I appreciate the eyes on this one for those who make it to the end ...
My wife and I spent about 6 hours carefully searching. We started in this field that Drone Flying Captain https://goo.gl/maps/KRiKUtm7U2J2 posted above (Thanks Drone Captain!). This large field is a new peach orchard, well tended, and we walked each row, nothing. The southern border is the 615 on google maps, the other 3 sides are perfectly rectangular. there was a guy clipping tree branches in one part of the field, he hadn't found it, he'll be in that field the rest of this week and beyond. I don't think he found it and hid to keep, seemed pretty honest. Other than a couple rows he had clipped that morning we walked each row
Then we moved over and searched the furthest half (the downwind of the trajectory line) of the field that had the last signal recorded in it. This one :http://www.phantomhelp.com/LogViewer/RWYSNP6DM7SHMER474FW/#
Nothing.
Then we searched the field downwind of the one that drone captain kindly marked as the most likely and that we had searched in the morning ... this field is overgrown but not too crazy. It is an irregular rectangle with a dry watercourse at the far end, the south eastern end. The south border is of course also the 615. Nothing. Then we searched the field on the other side of the dry water course from this field, and then walked the ditches of the 615 and the tall trees that border the 615 southern side. Nothing.
Then we started searching the sides of the fields closest to the 615 on the other side of the 615 opposite all the fields we had search in the morning. These fields are all bordered by narrow tall rows of trees that are cypresses they use as windbreaks here around the orchard fields as we get the strong north tramontane wind that caused my drone to fly off yesterday. So our thinking was possibly that the drone flew over the windbreak rows of trees that are maybe 50 feet high, had a reduction in wind speed, started to gain ground following the return to home function, then hit the 10 % and had to land.
Still nothing.
At that point it was time to go get the kids from school and a bit discouraged. I need your guys input on two things:
1 - our calculations
at the last signal the drone was at 135 feet and had been at that altitude for about 10 seconds, before that it had been at 155 feet for over a minute, before that at 188 feet pretty continuously for a while. Taking the last ten data points in the awesome flight record log you guys helped me locate and upload, it had been blown 168 feet further from home between 19 min 40.4 second and the last contact at 20 min 15.4 secs (5141 distance to home minus 4973 distance to home = 168 feet in 35 secs). This gave us a speed over ground of just under 5 feet further per second in the air.
Looking at battery consumption at 20 min 15.4 sec flight time = 1215 total seconds while battery goes from 100 % to 17 %, this gave us for each 1 % of battery = about 15 seconds flight time.
So from the last data point we figured the drone flew another 7 % X 15 seconds per 1 % = 105 seconds at which time it would have hit 10 % and started to descend.
So from last data point, about 105 secs X 5 ft/ sec distance lost = 505 feet further in wind direction before starting to descend.
From there, how much further did it blow before landing? hard to say but the trajectory of wind was very very consistent and we had searched the fields from the last data point to what seemed like at least 1000 feet from the last point.
So thanks in advance for reviewing our calcs and any great ideas or info we're not aware of
question 2:
when the drone hits 10 % and its is fighting to do a return to home (and losing ground at 5 ft per sec), how is the drone programmed to behave? It has collision avoidance on, there are lines of trees along the south side of the 615 and generally at the east end of fields as windbreaks. How does the drone behave if it detects a tree under or near it during that descent of the last 10 %? Or what would it do if it detected low bushes under the landing point - which there were in a couple of the further downwind fields? If it hit 10 % and was still at 133 feet, which seems probable, how fast does it go down and what would be the drift over ground as it moved closer to the ground?
If we take our calculations of the drone flying for 105 second or nearly 2 minutes before hitting 10 % and then dropping, but still losing ground progessively (less as it gets closer to ground) that seems to suggest from the last data point is might be ... ? 500 feet further at 133 feet altitude plus 200-300 feet for ground lost during descent?
We're kind of bummed, we searched thoroughly generally walking 10 feet apart and trying to keep to a grid pattern even in the overgrown bush.
So either my calcs are off; the maybe the wind direction changed somewhere and the drone is not on the trajectory continued out from the actual flight (although we searched the whole fields under its path to a distance of at least 200 feet or so to either side of its trajectory); or could it be something like the drone somehow made distance back towards the last data point as it dropped, maybe even during the last 10 % programmed descent? This last idea seems hard to believe but the sun is shining for another two days and I want that drone back. I'm game to keep searching but looking for fresh ideas.
Unless it landed on or near the road (and there are no drone pieces on the road lol) and was picked up, then this is probably about as good as you could hope for as a place to look for a lost drone.
Thanks very much!
Tris
Reading the commentaries I realise when the drone first got caught by the wind and taken away I compounded the problem by flying it higher thinking I wanted to maintain line of sight while waiting for the return to home function to access the power that I knew the drone must have to go at 50-60 km an hour in sport mode. Then I didn't have the confidence to just try to land it using the controller as I had only flown it 7 times and focused on line of sight for safety and landing, my main concern was not hitting a tree or something like a bush when landing and thus destroying it or the camera gimbal. I honestly never thought there might be some kind of limit on the power it could access to return home.
Just hoping this wasn't a 1500 $ lesson. |
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