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Professional stress cracks in rear two arms - warranty question about epoxy

Discussion in 'Phantom 3 Help' started by rmfa, Oct 21, 2015.

  1. rmfa

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    I had stress fractures in two of my rear arms. I used epoxy to seal up the tiny cracks and have not had any more cracking. Sunday, after 210 successful flights with no issues otherwise the P3 dropped out of the sky from about 200ft. Its like the thing lost power. The flight was only 1 minute long. You can see it here:

    HealthyDrones.com - Innovative flight data analysis that matters

    I need to send this back to DJI but I'm worried about the epoxy. What do you guys think? I think I can use my dremmel to get view of the screw heads but I don't think I can get it all out.
     
  2. LuvMyTJ

    LuvMyTJ ADMINISTRATOR
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    I do not know this first hand but some here said the DJI repair preformed for them was in fact epoxy. Besides, the epoxy wouldn't cause the issue you described so why should it matter?
     
  3. rmfa

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    Thanks, anyone else?
     
  4. Yt2

    Yt2

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    I think if you put anything additional on to the aircraft the manufacture will try and blame it for any repairs. Oh the epoxy weakened the surrounding area, Oh it made it unbalanced, Oh what is he hiding under there and so on. By doing what you have done, I fear any warantee has gone west...
     
  5. alebrije

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    IMG_3318.JPG I just noticed cracks on the screws on two of the arms. I bought my drone a year ago so no guaranteed. I am buying the plastic plates to reinforce the screws areas on the four arms. Stress cracks are result of the screws been too tie at the time of the manufacture. Not sure what else I can do. Any ideas?
     
  6. geobee

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    According to several posts, cracks under the motor mounting is very common, I purchased the metal retro fit plate kit and fitted to my Phantom before it even left the ground due to being advised by several current owners of the machine. Looks like yours has displayed the exact problem I was warned about. Motors must be too powerful for the factory design and puts stress on the plastic. I was told it happens when the motors are being slowed down from full RPM as they cause a surge and the plastic must twist causing the break.
     
  7. Jthomp

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    By your last statement I understand the stress cracks are at, near, or around the motor mounting screws. These cracks are USUALLY caused by over-torquing of the mounting screws, or by use incorrect-length screws (such as those that are used to mount some types of prop guards on the P3S). The cracks CAN be caused by impact damage, as well - especially if the impact happens in conjunction with either of the above-noted situations.

    By themselves these kinds of cracks won't cause a power failure - unless structural failure of the arm itself causes the motor to break off or to twist out of alignment.

    DJI is not likely going to repair or replace the shell under warranty - especially since you have flown the 'craft over 200 times and now have experienced a physical crash - unless you can supply flight data which shows the crash was the result of a failure of a factory design or a factory component failure.

    Be adventurous - buy a replacement shell and replace the cracked one yourself. If you are careful, and if you take care to watch the YouTube videos on how to do that, you will not only find it pretty easy to do, but you will learn a whole lot about your drone in the process.
     
  8. epicdoom

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    Id be inclined to think as long as its within the warranty period DJI would have to fix or replace it, one or the other. I took matters into my own hands and fixed mine, then installed the metal motor plates which I have removed several times now with no additional cracks to be found. the repair I did was to use a small triangle shaped file like a jewelers file. I used the edge of the file along the crack to bevel a V shape in it, just lightly don't have to go into the plastic to deep you just want a little more surface area for the epoxy to bite onto. I spread a thin coat of epoxy along the crack let it dry 24 hours wrapped a piece of 400grit sandpaper around a popsicle stick and leveled the surface then installed the motor plates. use 5 min epoxy for the repair a longer set up time epoxy is stronger but you will have to keep moving it over the crack the entire time till it sets up and stops running.
     
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