P3P Falls Out of Sky within a few seconds...WHY?

[Sean808080]

This is my second refurbished P3P from DJI. Here is the flight data link:
Airdata UAV - Flight Data Analysis for Drones

Here's the video:

The bird goes up and within a few seconds something happens, it comes crashing down just missing me and breaks the camera and gimbal.

The flight data shows loose or missing propeller. I don't know why I definitely tightened them and **** WTF?!?

Now I'm entering the gates of DJI Support hell....What's the likely outcome here?

Not happy at all.

 

[Phantom-Paul]

We feel your pain!
Were all 4 propellers still attached after the crash?
I would sync my flight data with DJI and get straight on to customer support if you feel its a warranty claim.
Also upload your log file here https://www.phantomhelp.com/LogViewer/Upload/ and post a link so people smarter than me can take a look see.

 

[Sean808080]

Nope one prop was in the grass.

 

[Sean808080]

Logs here Phantom Log Viewer - PhantomHelp.com

 

[rockydog]

Looking at it on a 27" screen, between 39 and 40 seconds you can see the prop come off and fly up above the P3 as it starts to tumble. I have a bad feeling that you won't get very far with DJI, but best of luck.

 

[msinger]

Looking at it on a 27" screen, between 39 and 40 seconds you can see the prop come off and fly up above the P3 as it starts to tumble

Right on. The prop most likely either flew off because it was not attached properly or it was damaged. I don't think DJI is going to cover this under warranty.

 

[Sean808080]

OK very good catch! How do propellers fly off Did the motor seize? This isn't my first drone flight by any stretch. Any other ideas?

 

[msinger]

Did the motor seize?

The motors always seize when you turn them off post-flight. I've never heard of the props flying off then, so it would be highly unusual for a prop to fly off even if the motor did somehow seize mid-flight. If you want to rule out that idea though, you could review the DAT flight log in DatCon.

 

[syotr]

During normal flight, the direction that the motor is turning tightens the prop. If the motor stops suddenly, inertia will keep the prop spinning in a direction that unscrews it. This won't happen at slow speeds as when motors are shut off after flight, only when the prop is spinning very fast. My guess is that you have a problem with one ESC. It may be intermittent and not show up in testing. When you buy a refurbished model, you may be buying someone else's problem.

 

[Sean808080]

Thanks all for the guidance. The drone actually doesn't look terrible. Just the gimbal arm broke. The camera seems to be working as well as can be.

I got the DataCon version of the .dat file. Link is Dropbox - FLY004.log.txt

 

[msinger]

That's not the correct DAT file. The file should have a ".DAT" extension.

 

[Sean808080]

It was derived from the .dat file matching the doomed flight. Not right?

 

[msinger]

Check out these instructions.

 

[Sean808080]

Yup I used those instructions to get the dat if that's the file to look at here it is. Dropbox - FLY004.DAT

 

[HWCM]

During normal flight, the direction that the motor is turning tightens the prop. If the motor stops suddenly, inertia will keep the prop spinning in a direction that unscrews it. This won't happen at slow speeds as when motors are shut off after flight, only when the prop is spinning very fast. My guess is that you have a problem with one ESC. It may be intermittent and not show up in testing. When you buy a refurbished model, you may be buying someone else's problem.

He would have an ESC error on his screen and in the logs.
It most likely was just not installed tight enough , improperly or was worn.

 

[Sean808080]

The drone is NEW to me. It was refurbished and this was the first flight outside of my back yard. The other thing I noticed is that the drone still had the previous owners name on it. Does that indicate that it was not properly refreshed? The props were new and I made sure to hand tighten them after mounting them. Camera is working but the gimbal arm is broken. Sigh...

 

[msinger]

Your flight log shows none of the motors seized. The graph below shows the front, right motor dramatically sped up after the prop flew off.

 

[BudWalker]

Yup I used those instructions to get the dat if that's the file to look at here it is. Dropbox - FLY004.DAT

I took a quick look at the .DAT. There were the usual indications showing that the right front prop either broke or flew off. But, there were no indications of an ESC problem that would have caused the motor to stop which, possibly, could have then caused the prop to spin off. Since this is a refurb unit have you checked the condition of the threads on the right front motor shaft?

 

[HWCM]

You really need to tighten them more than hand tight.

 

[Pharm]

FWIW, I put a tiny amount of clear silicone caulk inside the threads before putting them on and let it sit a few days. I never take the props off and I still check them before each flight. It may be a false sense of security but it eases my mind a bit.

"Hand-tightening" is a very subjective term. What I consider hand-tightened might be too loose for your taste or way too tight.