chbrian.cheung
lvl.1
Flight distance : 40525 ft
Hong Kong
Offline
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@Alari RTH was initiated by the disconnection between RC and the aircraft.
Not trying to justify myself or whatever here,
With the data provided by the flight log, the last known location was 22.37440219N 114.1959707E
So, I have done a bit of physics here.
Considering the last few data that the log provided. It indicated that the aircraft had no change in yaw (so we could reasonably assume that its direction was pointing to home)
If it kept heading back to home, that is, RTH working normally, it should not have hit the pole. (Moreover, fyi, the altitude of the highway was even lower than the home point. And a typical pole has an height of less than 6 meters in Hong Kong. Note that the altitude above home point was 128.9m, way higher)
Assume that it got hit by a fast moving object (to be reasonable, say, a bird) and the battery came out, the drone lost its power immediately, with a horizontal velocity Vx = 1.7ms-1 and vertical velocity Vy = 0.
So we are now considering a projectile motion, (Autorotation is neglected for the sake of calculation and with the relatively heavy drone body when compared to the light and thin propellers, autorotation would not take any significant role here.)
Vertical motion:
By s = ut+1/2 at^2 ........ air resistance will be neglected as the drone has an aerodynamically favourable shell and heavy body.
(128.9+31.55) = 0 + 1/2 (9.81) t^2 ........ 31.55m was added to the equation to get the maximum range of motion when we later calculate the horizontal distance that it could travel.
t = 5.72s
Horizontal motion:
v = u +at
v = u ....... again, a = 0 as the air resistance in the x-direction was neglected to deliberately overestimate the range of horizontal motion.
So for the 5.72s, it could have travelled 5.72*1.7 = 9.72m ~10m
Look at the map again, for this distance, it would have dropped onto the highway if it travelled along its initial direction. Yes, @leanlinao. After doing some real calculations it should be on the highway. And you may want to check the exact location based on the evidence provided by the GPS.
But after driving out to the highway immediately, nothing was found.
So if RTH was working normally, it should have been on the highway. |
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