Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

Crack Repair Kit On Amazon

Discussion in 'Pro/Adv Discussion' started by jimerb, Aug 21, 2016.

  1. jimerb

    Joined:
    Nov 29, 2015
    Messages:
    178
    Likes Received:
    37
    Ken Hanks and Phill2 like this.
  2. Lifted Chevy

    Joined:
    Jun 30, 2016
    Messages:
    135
    Likes Received:
    51
    Location:
    Los Angeles
    I just ordered these so hopefully I never see cracks. Hopefully !
     
  3. Phill2

    Joined:
    Dec 4, 2015
    Messages:
    274
    Likes Received:
    46
    Just grabbed a set off ebay
     
  4. DeputyDrone

    Joined:
    Oct 8, 2015
    Messages:
    66
    Likes Received:
    20
    How much do they weigh? Will this shorten flying time with the added weight?
     
  5. Vertigo

    Joined:
    Jun 12, 2016
    Messages:
    499
    Likes Received:
    148
    most cracks Ive seen appear on top, so I doubt these would help at all. And yeah, they will reduce flight time, though likely hardly noticeable.
     
  6. Ted4797

    Joined:
    Nov 23, 2015
    Messages:
    978
    Likes Received:
    157
    Location:
    Florida
    one second per gr. that's what I hear
     
  7. jimerb

    Joined:
    Nov 29, 2015
    Messages:
    178
    Likes Received:
    37
    I think what it's doing is adding a thin metal plate below the arm attached right to the rotor. Basically it's making the plastic area holding the rotor no longer load bearing.

    Since I'm out of warranty, this seems like a much more economical way to do this repair instead of sending it to DJI.


    Sent from my iPad using PhantomPilots
     
  8. sjp0eqt

    Joined:
    Jan 20, 2016
    Messages:
    66
    Likes Received:
    33
    The only problem with the product shown by the original poster is that reinforcement plate if flat. You REALLY want the ones that have the built-in inserts, see below.
    They will fit better and provide more strength. It is IMPORTANT to not over-tighten any of these screws.The longer two (not the motor mounts) are going into a molded-in threaded insert that will break loose from the plastic if any force is put on them.

    upload_2016-8-22_18-47-8.png
     
  9. lablover

    Joined:
    Oct 24, 2015
    Messages:
    36
    Likes Received:
    3
    Where does one get these plates? Pretty slick
     
  10. HWCM

    Joined:
    May 2, 2016
    Messages:
    657
    Likes Received:
    138
    The ones the OP posted have the standoffs. The picture you posted has them sitting over the holes. Look at his link again and you will see the posts next to the screws. It also uses countersunk screws. The idea is to take the pressure off of the screws on the plastic and have the screws holding the metal to the plastic.
     
  11. Silverwingflinx

    Joined:
    Nov 5, 2015
    Messages:
    511
    Likes Received:
    145
    The strong arms don't work!!I still got cracks I have used carbon fibre and the alloy...still cracks on my shell!!! Got rid of them!!


    Sent from my iPad using PhantomPilots
     
    bluer101 likes this.
  12. HWCM

    Joined:
    May 2, 2016
    Messages:
    657
    Likes Received:
    138
    I figured.
    I had read somewhere else that people were still getting cracks while using these.
     
  13. alokbhargava

    Joined:
    Sep 28, 2015
    Messages:
    5,114
    Likes Received:
    1,648
    Location:
    San Francisco, CA
    Initially there were tons of complaints for cracks, DJI started replacing free, they also controlled shell material and forming process. On the other side people started using strengthening plates. Crack complaints drastically reduced on forums.

    What actually finally reduced the complaints is not known but it's true strengthening plates will reduce chances of developing cracks.


    Sent from my iPhone using PhantomPilots
     
  14. Silverwingflinx

    Joined:
    Nov 5, 2015
    Messages:
    511
    Likes Received:
    145
    This is what reduced my cracks!!! After 8 shell replacements!!
     

    Attached Files:

  15. sjp0eqt

    Joined:
    Jan 20, 2016
    Messages:
    66
    Likes Received:
    33

    Nope, you're totally mistaken. The OP has a FLAT mounting surface where the motor screws are and SEPARATE BUSHINGS for the other 2 mounting holes. The units I endorsed have integrated sleeves on ALL 6 MOUNTING HOLES. There's a huge difference, look again.

    Without the integrated sleeves they can neither fit as well nor disburse load as well.
     
  16. sjp0eqt

    Joined:
    Jan 20, 2016
    Messages:
    66
    Likes Received:
    33
  17. Vertigo

    Joined:
    Jun 12, 2016
    Messages:
    499
    Likes Received:
    148
    They pretty much cant work. They may "work" if the root cause is over tightening the bolts, but in all other cases, its the weight of the quad that is being pulled by the motors. Imagine the shell was made of soft rubber, now lift it by the motors, and you can imagine where it will bend first: there where its thinnest.

    You can add steel reinforced concrete blocks under the motors if you want, but those arms are still going to need to cope with the weight and vibrations of the quad and those reinforcements will do absolutely nothing IMO. You'd probably get better results from tying some kevlar wire around the arms, and then cross them below the frame and tighten the wires.
     
  18. dbastille

    Joined:
    Aug 31, 2015
    Messages:
    8
    Likes Received:
    1
    My experience is very positive for supporting plates under motors.
    I ordered the quick connect prop guards the same time as I got my p3a and installed the mounts before my first flight. What I noticed was how thin the wall is where the original screws seat in the plastic. What the blocks did for me was give that seating area a much thicker base and move the pressure evenly around the back while totally removing it from the original plastic countersunk areas.
    After a year and a half of many flights l have zero stress cracks. This is the reason I left the mounts on even though I'm rarely using the guards. I'm not sure if this will help much with previously cracked arms but goes a long way in keeping the motors in place if things go bad.
    I like both designs that are on this thread but since I'm a machinist by trade I prefer the CNC machined ones rather than the cast ones.
    They look very professional.



    Sent from my iPad using PhantomPilots
     
    iAm likes this.
  19. HWCM

    Joined:
    May 2, 2016
    Messages:
    657
    Likes Received:
    138
    Those other stand offs make no difference as the plates rest flush against the arm at those points, the sleeves on those four holes do not rest on anything, they just slightly go into the screw holes. They do nothing. The reason for the rear standoffs is because the arm bends at that point and the plates are not flush. These stand offs rest in the screw holes of the same plastic that cracks. So there is no strength gain there either....but think what you want. Users of these plates still get cracks. The plastic is brittle, being in the sun probably accelerates the break down, plates or not.
     
  20. HWCM

    Joined:
    May 2, 2016
    Messages:
    657
    Likes Received:
    138