An aside: Would you please advise me: what do I need to do to access the granular telemetry report as shown in the above post. Thanks very much for your consideration.
Signed: very assured and always learning.
Fell out of sky, Mini2
- Thread starter goldensky
- Start date
Signed: very assured and always learning.
The problem starts at 1:17.1 when there was a warning of a blocked motor not rotating properly.
Straight away the drone pitched backward, rolled over to the right and was tumbling to the earth.
We have no way to tell if it was a failing prop ... a motor, or something else that prevented the motor to rotate & thereby lose thrust. This as the mobile device .DAT log which includes motor data is encrypted for the Mini 2 & can only be read by DJI staff.
... and to get that chart you feed in the downloaded .CSV file from PhantomHelp into the free software CSVview which you can download here --> CsvView Downloads
the props and motor are in great shape... they move and spin freely
i flew it in sportmode hard lastnight at about 6 ft AGL across a soccer field for 20 minutes, no hiccup , and my dog was exhausted from chasing it.
i flew it in sportmode hard lastnight at about 6 ft AGL across a soccer field for 20 minutes, no hiccup , and my dog was exhausted from chasing it.
only thing left , that i can imagine hapening , is i might have been struck by an aggressive fast flying bird, i didn't see any birds around , but i was looking at the screen the whole time
ok further inspection of the right rear motor is showing signs of resistance when compared to the other 3 motors..
has a slightly bent shaft
has a slightly bent shaft
Increased current draw required to counter that higher rotating resistance is definite risk for "excrement hitting the fan".
Though that should cause warning messages. Increased drag from icing on propellers does that.
(I've had this kind growth in them)
And why that hard 20 minute flying didn't cause anything?
I wonder if bird hitting propeller of that motor could have caused the crash and bent that shaft...
When you get prop icing the increased current draw comes from that the FC commands an increase in motor RPM to counter the decreasing thrust generated by the iced prop ... so no, a iced up prop doesn't have more drag ... it have less drag due to that the ice build up alters the prop shape in a way that the prop pitch decreases.
The motor & "notEnoughForce" error you get from prop icing is due to that the motor spins on max RPM's & can't obey the FC about even more RPM's.
If a bird hits a drone we rarely see a "one step" motion ... it usually consists of one big uncommanded movement, then a stabilization phase ... & if the strike damaged a prop ... the drone flies erratic & unstable until the damaged prop breaks off, & then it goes down in a spiral. A bird strike don't bend the motor shaft & and leave the prop undamaged...
Got literal motor current warning when there was similar to this icing in propeller leading edges:
Icing Research - Glenn Research Center | NASA
We don't see that amount of icing on drone props ... the drone have gone down long before the props have accumulated that kind of ice build up.
Guess my MPP didn't get the memo that it should have fallen down like a rock...
Because there was precisely that kind of forward protruding ice spike growth in millimeter/two scale on inner ~third of the blade near motor.
I'm not following you ...
Have you investigated a great number of DAT logs from several years of prop icing incidents ... have you actually seen the motor current increase even though the motor RPM decrease? If you share that DAT log from the MPP I can point out what happens.
To me it appears that you just speculate wildly ... EMP bursts, bird strikes, prop icing & all without looking into & point to supporting evidence from the log.
If you had looked into the log you had seen that the weather conditions wasn't typical for prop icing ... +6C degrees, overcast, 60% humidity & a dew point on -1,2C degrees ... this together with no motor related errors at all in the log (which we always see in documented prop icing cases) strongly suggests that this was no prop icing.
And even though the OP discovers that the motor shaft is bent on the same motor that the telemetry suggests ... you continue to speculate & disregard the obvious?
I was talking about my latest case of propeller icing.
Motor RPM definitely didn't change from normal needed for hovering.
Unless remote's telemetry display wasn't telling the truth.
Share the DAT ... without that all this is useless & will continue to be speculative. Also create your own thread about it instead of cluttering up the OP's thread about a Mini 2 that didn't suffer from prop icing ... all this just make it confusing for others that read this to learn what to do/not to do & what to think about when using their Mini 2's.
Just wanted to post this for reference as it seems similar to what the OP experienced. Apologies for the lengthy post.
My Mini2 has reported "motor unable to rotate" messages just about everytime I attempted to fly in "cool" temps since receiving it from DJI in early November. The right rear motor would not start. Definitely felt resistance of that motor when spinning manually. The other 3 motors spun freely. No visible misalignment of motor shaft. No crashes or near crashes - happened since brand new.
After spinning the right rear motor manually and re-attempting takeoffs, the Mini2 would fly normally. But same resistance and "unable to rotate" message if I brought the AC down, changed battery, and attempted to fly after a 5 minute "rest". Once airborne, there has been no issue, but I have not flown in temperatures below freezing.
My situation indicates a direct cause & effect relationship on cool weather/temps. I am suggesting a possibly similar situation for the OP's AC -- colder temps at higher altitude (150 feet) and in snowy conditions chilled the AC motor and caused motor's failure to rotate.
Just a suggestion.
My AC is on it way back to DJI for assessment. I specifically mentioned to DJI that I was concerned about a motor failure or unable to rotate situation once the AC was airborne. The OP's incident strikes me as exactly what I feared would happen to my AC.
My Mini2 has reported "motor unable to rotate" messages just about everytime I attempted to fly in "cool" temps since receiving it from DJI in early November. The right rear motor would not start. Definitely felt resistance of that motor when spinning manually. The other 3 motors spun freely. No visible misalignment of motor shaft. No crashes or near crashes - happened since brand new.
After spinning the right rear motor manually and re-attempting takeoffs, the Mini2 would fly normally. But same resistance and "unable to rotate" message if I brought the AC down, changed battery, and attempted to fly after a 5 minute "rest". Once airborne, there has been no issue, but I have not flown in temperatures below freezing.
My situation indicates a direct cause & effect relationship on cool weather/temps. I am suggesting a possibly similar situation for the OP's AC -- colder temps at higher altitude (150 feet) and in snowy conditions chilled the AC motor and caused motor's failure to rotate.
Just a suggestion.
My AC is on it way back to DJI for assessment. I specifically mentioned to DJI that I was concerned about a motor failure or unable to rotate situation once the AC was airborne. The OP's incident strikes me as exactly what I feared would happen to my AC.
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