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N3 Motor shutdown while in flight
541 5 2017-1-31 12:51:54
Arbutus
Beginner
Flight distance : 8221
Canada
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New N3 on a Q500 'X' frame. 4S, 900kv, 11x4.5 props.   Aircraft is stable, predictable, responsive.  Flight modes are P/S/G. Testing done in G mode.

In flight, all motors stop. Not powering down - I mean stopped with braking.   This has happened twice now.  After repairs I simulated the situation at the workbench, reproducing the problem.  

1:  Powered on, motors armed and spinning
2:  Running without R/P/Y control input, 50% throttle, horizontal on the workbench.  No issues, motors run continuously and respond to throttle input.
3:  Motors shutdown on command (simulated landing).  All  is normal so far.
4:  Start motors, run for 1 minute on the bench, 50% throttle
5:  Pick up the aircraft by hand and move around the room.  Motors appear to respond to attitude changes, normally.
6:  Pitch > 10 degrees causes instant motor stop.
7:  Roll > 10 degrees causes instant motor stop.

Log files are available. YouTu.b.e available.

Is there an attitude threshold that is triggering this behavior?  e.g. >10 deg when groundspeed ~zero?
Is there an anomaly with respect to altitude?  e.g. I could see this behavior as being correct (motors shutoff at extreme attitudes) if for example the aircraft was at zero altitude when it would be tipping over.  But not if it is airborne.

The first crash was from about 3m altitude  when the motors stopped and the second at about 8m. Flight conditions, GPS, RSSI were good, batteries fresh, etc.



2017-1-31 12:51:54
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doug.xtremevisi
Hobbyist
United Kingdom
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wow that does not sound good! I hope someone can help you with this - DJI??
2017-2-5 09:19:47
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DJI-Jamie
DJI team
Flight distance : 34239
United States
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Just to clarify, what do you have your CSC shut off set to? When the motors stopped via pitch or roll, were you holding down any other commands like elevator or throttle? Do you use LB2 as a RC or a SBus RC/Receiver combination? Are your sticks set to mode 1 or 2?
2017-2-7 14:00:25
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Arbutus
Beginner
Flight distance : 8221
Canada
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DJI-Jamie Posted at 2017-2-7 14:00
Just to clarify, what do you have your CSC shut off set to? When the motors stopped via pitch or roll, were you holding down any other commands like elevator or throttle? Do you use LB2 as a RC or a SBus RC/Receiver combination? Are your sticks set to mode 1 or 2?

This is an SBus system.

flightlogs:  these are the compressed logs from the crash yesterday.

(also posted to RC groups)

https://www.dropbox.com/sh/6b3i5 ... f4azx6DqffEAha?dl=0

If I hold the aircraft and 'fly'  I can produce another log - is there any specific behaviour or aircraft attitude/setup I can test for you?

Your help is very much appreciated!

Regards,
Don Gibson
HighCee Technologies
http://highcee.com
2017-3-20 11:50:18
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Arbutus
Beginner
Flight distance : 8221
Canada
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2017-3-21 18:36:23
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Arbutus
Beginner
Flight distance : 8221
Canada
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Arbutus Posted at 2017-3-20 11:50
This is an SBus system.

flightlogs:  these are the compressed logs from the crash yesterday.

No other control inputs are causing the motor stop.  In the first crash it was flying forwards and gaining altitude under pilot control, everything normal, then STOP!

Video posted showing the behaviour at the workbench
2017-3-21 18:38:26
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