P3P crash root cause speed error?

@cheddarman If what you describe is true ( The OP never stated if this aircraft had previous stress cracks ) then that would be the case for both motors. This is more likely an artifact of the crash, however it is possible.

ARMS.png
 
Wow! I didn't notice this glue before, good catch! no words to say , then yes, this thing was repaired before I know for sure glue wont keep things together for long time . Looking forward to buy a reinforced one, link please? I just dont want to end up buying a crappy Chinese one.
 
FYI this aircraft was purchased on ebay , one more thing to inspect on arrival.
Well, that should answer the cause of the motor failure and crash. Had that been stated previously, diagnoses would have been much easier. As you say however, you did not notice.
 
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I'm sorry, how on earth could you not notice those (repaired) cracks! The blinking motor mounts are in pieces and should never have been flown! Grrrrrr!
 
@porrascarlos80 .. That would also explain why the data appeared much like to be a lost prop. Scenario being the motor mount severed, causing the prop to impact with the shell and it got worse from there. I am very surprised the props were still in tact. Just for the sake of asking and you did not specify. Which 2 motors are these? If they are the same as the other images, one is left front or right rear. Hard to tell on the other.
 
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When I had seen those pictures, it was obvious that has been repaired, and it is known as motor stress points.

Search results for query: motor stress

I have made these repairs myself....

Rod
 
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Thanks for all your analysis and comments. So far I have learnt :

- phantom 3 has several shell models, some are more reinforced than others.
- few motherboard versions do exist and motors may not work with some other.
- inspect a drone carefully when purchased used from ebay :(
- Drones doesn't have inner frame its just plastic holding motors in place . It would be great to have a drone with bottom shell made from carbon fiber.


More info:
Blades were black ones, made of carbon fiber. See picture attached. Looks like then when the motor base broke, then the blade hit the top shell causing that mark.

Well nothing more to say , now repair or replacement has to happen.

Thank you all !!!
 

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I have seen, on the arm/s of a phantom, arc mark/s similar to the one you show but without the heavier mark at the clockwise end of your mark.
 
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Thanks for all your analysis and comments. So far I have learnt :

- phantom 3 has several shell models, some are more reinforced than others.
- few motherboard versions do exist and motors may not work with some other.
- inspect a drone carefully when purchased used from ebay :(
- Drones doesn't have inner frame its just plastic holding motors in place . It would be great to have a drone with bottom shell made from carbon fiber.


More info:
Blades were black ones, made of carbon fiber. See picture attached. Looks like then when the motor base broke, then the blade hit the top shell causing that mark

Thank you all !!!
Almost certainly from blade contact, probably after the motor broke free from. its mount.
 
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@porrascarlos80,

I left mine set upside on the props for a week or two, seemed less likely to knock it over in my cluttered garage. :rolleyes:

When I started it up one of the props was clicking. Yes it was hitting the housing, I really looked thinks over started numbering the props moving them around, etc.

Decided it was just the one prop and both tips were hitting the housing?

If I recall the spacing was different from the front props and back props to the housing. When I swapped props none of them were hitting. That was the confusing part and why I looked closely at the motors, props, etc.

This is a unit that I had made repairs to the shell. The P3A I'm using now, somebody else made the repair and has quick release prop guards with out the prop guards installed. This is what some do to strengthen this problem area.

Rod
 
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The speed error is unrelated to the incident. Those occured during the tumble. That is related to the IMU positioning and Velocity Calculations. It certainly looks like a lost prop as you released the elevator.
View attachment 114201
Where did you get the data for this plot FlyDawg? I can't see anywhere he uploaded a .DAT file?
 
Okay, so how does one convert the .txt file to a graph. Looks just like the graphs from CsvView but that won't read .txt files?

Sorry, steep learning curve for an old man :rolleyes:

Ah, think I've found it. You have to download the Verbose Csv data from the Flight log!
 
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Okay, so how does one convert the .txt file to a graph. Looks just like the graphs from CsvView but that won't read .txt files?

Sorry, steep learning curve for an old man :rolleyes:

Ah, think I've found it. You have to download the Verbose Csv data from the Flight log!
CsvView will read the .txt directly.
 
I I have found out how to do this, I think. At the top of the 'txt printout there are several options as to what you can do with the data displayed and one is to "Download Verbose Csv". This then converts the .txt into a .csv and this can be read by CsvView! :p

Screenshot 2019-09-08 at 08.37.10.jpg


I haven't quite worked out how to produce the graph FlyDawg did on post #9 of this thread but I'm learning!!
 
I haven't quite worked out how to produce the graph
That was created from the .txt log. Not the Verbose .csv. They will both work however. The Verbose .csv can also be read in Excel, whereas the .txt file cannot.
 

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