Fell from sky
- Thread starter jeffgiff
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Yup. See post #2 for instructions. Click on that link, follow the instructions then post a link back here. These guys are really good deciphering the data.
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Meta4
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The flight data shows none of the usual indicators of something you might have done wrong .
The battery in particular was fully charged at launch time and still healthy at the end.
At 1:31.2 the trouble started. You just eased off on the sticks after going fast and up in Sport mode and it was all downhill from there.
The error messages suggest a genuine hardware malfunction and the case looks like one to take up with DJI.
Upload the flight record to DJI - click on the cloud icon on the flight record page in the app.
Then go to their online help at: DJI Support - Phantom 4
Click Online Support at the bottom of the page and start a chat to get things started.
Not sure I necessarily agree. It looks to me like it probably lost a prop at 89.8 seconds, with the usual resulting pitch/roll/yaw oscillations and rapid descent. There is a slight discrepancy in the yaw direction relative to pitch and roll that could imply an ESC failure, but I'd need to see the DAT file to be certain.
I agree with this. Clearly a propulsion problem at 89.8 secs. Either a lost/broken prop or a motor/ESC failure.
Meta4
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You guys are right, the trouble started a couple of seconds earlier.
I was surprised at the speed the Phantom attained while falling.
Its terminal velocity was 58 mph.
Although it's unrelated to the crash, I was also surprised at the joystick inputs given during the fall.
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All props attached. Is there a way of uploading the dat files for you folks to look at? This drone has an interesting history and a rather lengthy story regarding dji warranty/support. Including the swap of a good battery for one that has the dreaded one bar blink. I sent the bird back to dji after two months of purchasing new, when it began to have esc errors. After djis keen support staff assessed it they determined that these errors were the result of a non flght impact. They said this was obvious due to the cracked upper and lower case and landing gear. This of course baffled me as I had sent the a perfect drone. Not a scratch on it with only 9hrs of flight. So i thought it must have been damaged in shipping and would deal with it when i got it back. So I had dji send it back without repairing it. Paid the postage. On return, would you believe it was exactly as I had sent it! Perfect, not a scratch on it with the exception of one of my brandnew batteries being swapped out for an old one that didn't work! I have all of this correspondence in emails. I have never been so pissed at a company.
I then took the drone to my local dji dealer who replaced an esc. This flight was the second since that repair.
I then took the drone to my local dji dealer who replaced an esc. This flight was the second since that repair.
How to retrieve a V3 .DAT File from the AC
Upload to Dropbox or similar and then post the link here.
Yeah, please Dropbox the .DAT as @sar104 suggested. A history of ESC issues would be an obvious reason for a propulsion problem.
Hmmm... From the .txt I was thinking the problem was in the right front. What about you @sar104 ? But, the invoice shows it was a CW motor which would be the right back or left front.
Agreed. That relates to the discrepancy in the yaw data that I mentioned previously. The aircraft rolled right and then pitched forwards, suggesting loss of lift front right, although there was a strangely long delay after the right roll started before the forward pitch.
However, looking at possible scenarios in relation to the yaw, given that the front right is a CCW motor: (1) the expected result of prop loss is that the the prop flies off as an angular momentum trap, takes CCW momentum with it, which has no effect on the angular momentum of the aircraft, but the opposite CCW motor throttles down to balance lift around the COG and the two remaining CW props throttle up to increase lift, both leading the aircraft to yaw CCW or (2) the motor seizes and the CCW angular momentum of the prop and motor is transferred to the aircraft, making it yaw CCW in conjunction with the effects listed in (1) that will also occur.
Either way it should yaw CCW on losing a CCW motor, but the aircraft actually yawed CW, not CCW, implying loss of a CW motor. We need the DAT file.
The only thing I can add to this is that the sample rate of the .txt is just too low to really tell the difference between CW and CCW. Here is an incident where a propulsion issue occurred and the P3S was rotating CCW.
This plot was generated from 30 Hz data. The same data sampled at 10 Hz (the .txt file sample rate) produces this plot
I can't really tell if this is CW or CCW.
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