Please Help Quad Destroyed

flyNfrank said:
My voltage was sure jumping around just before it dropped from the sky.

That was the first thing I noticed on your posted data, and the most telling information of an impending failure....
 
I put a couple images below from a kml file that shows them in google earth. The 1st image shows the flight path with the elevation mapped into it. The point where the yellow arrow points to is where my quad dropped from. You see the end shows the quad lifted in altitude and began steering to it's right even though I had the lever straight on.

The 2nd image shows us the elevation changes in a graph view. Keep in mind when looking at these images, I had the controller at 100% throttle all the near the end.

In watching this while looking directly at from a 200ft away, the quad was flying straight at me, and rolled over.
 

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mede8er said:
flyNfrank said:
My voltage was sure jumping around just before it dropped from the sky.

That was the first thing I noticed on your posted data, and the most telling information of an impending failure....

The worse part about the voltage data is. That particular data stops roughly 20-30 seconds before the point in which the quad dropped from the sky. When I look at the point of the flight path that matches the voltage data, it shows some signs similarity as when the quad was near the point of dropping. But the end of the path is more exaggerated. So I'm guessing the voltage was close to being in the 9 something volt range when it stopped in the sky.
 
flyNfrank said:
..... a little over 48mph, which is no big thing for me or my quad. To slow it down I do the usual and flip it back into GPS mode and reverse the throttle.

I notice in this ESC report on 'Causes of motor/ESC failures' the author recommends avoiding rotation interruption in flight...

There's the possibility that an abrupt change in direction, for which the four motor speeds are suddenly changed and redistributed, combined with prop wash, *may* cause a temporary stall in rotation triggering an ESC failure.

http://forum.dji.com/forum.php?mod=view ... es&lang=en

I wonder if that is what caused this incident.
 
Hughie said:
flyNfrank said:
..... a little over 48mph, which is no big thing for me or my quad. To slow it down I do the usual and flip it back into GPS mode and reverse the throttle.

I notice in this ESC report on 'Causes of motor/ESC failures' the author recommends avoiding rotation interruption in flight...

There's the possibility that an abrupt change in direction, for which the four motor speeds are suddenly changed and redistributed, combined with prop wash, *may* cause a temporary stall in rotation triggering an ESC failure.

http://forum.dji.com/forum.php?mod=view ... es&lang=en

I wonder if that is what caused this incident.


Excellent observation.
 
Well it wouldn't make sense to do the mod if you couldn't fly it with a little aggressiveness. These parts are advertised as performance parts. More torque, more rpm's
 
flyNfrank said:
Well it wouldn't make sense to do the mod if you couldn't fly it with a little aggressiveness. These parts are advertised as performance parts. More torque, more rpm's

Agreed, I was simply trying to conclude what may have caused the incident; not suggesting it would be unreasonable to expect the quad to be able to be used that way. I have worked as a software design engineer for 30 years and although software quality is an easy target, if a piece of software behaved the way this piece of hardware does it would never make it out of the door. DJI might be basing their constaints and limitations on the fact that this is a quad and if you do lose one motor/ESC then it is pretty much game over anyway. I dont think that is good enough. In fact, since there is a 100% dependency on all engines in order to fly, it means it is *more* important to protect the ESC, not less. It should be designed to temporarily cut out and then cut back in. For goodness sake they are not even current limiting with a fuse. The ESC design may be elegant in some ways, but it is not robust and in my view is not fit for purpose in anything less than a hexcopter.

Anyway for me, I am now doing handcatch landing, and not flying in ATTI mode unless absolutely necessary. I am hoping that will be enough to mimimise my risk.
 
mede8er said:
IIRC you didn't update your esc's...is that correct????

My understanding from the posts earlier is that he did upgrade to V2.0 ESCs.
 

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