Well, the gorilla glue held but some new cracks developed.

What are you doing to get cracks? I’ve flown mine in lots of different ways but never had any problems?

Gary Oliver P3A Posted at 2018-5-13 14:44
What are you doing to get cracks? I’ve flown mine in lots of different ways but never had any problems?

Absolutely nothing. It is a factory defect of some sort. Some say the screws were over tightened and others say the plastic was too thin. The internet is full of people who have had the same issue. Unfortunately, I didn't notice until it was too late or DJI would have repaired it under warrantee.  

photojunky Posted at 2018-5-13 15:42
Absolutely nothing. It is a factory defect of some sort. Some say the screws were over tightened and others say the plastic was too thin. The internet is full of people who have had the same issue. Unfortunately, I didn't notice until it was too late or DJI would have repaired it under warrantee.

Yes unfortunately this is a very common problem. There is not much you can do about it to fix it, except keep the glue up to it, or replacement of the shell component.
Does it have any vibrations when flying?, prop damage etc?.

Thanks for the useful video.

Nigelbrinkmann Posted at 2018-5-13 17:14
Yes unfortunately this is a very common problem. There is not much you can do about it to fix it, except keep the glue up to it, or replacement of the shell component.
Does it have any vibrations when flying?, prop damage etc?.

No vibrations yet.  I am considering gluing the bracket to the shell with J&B Weld or Gorilla glue. It would be my last resort before replacing the lower shell. Replacing the lower shell is straight forward. Simply remove everything and put it on the new one I can do it but I really rather not.

Years ago there were batches of shells that were prone to cracking.  The suspicion was that the company pressing the moulds was using some recycled plastic to save cost instead of using virgin product.  This resulted in the plastic being more brittle and susceptible to vibration.  You might just unfortunately have one of those shells.

All you can do out of warranty is to continue to glue it and perhaps brace it with an additional piece under the motors (used for detachable prop guards).  If I were you I would also drill a very small hole in the shell at the end of the crack.  It is a well known and accepted method used in real aircraft repair to stop cracks continuing and getting longer.

Hi there, may I know how many drones do you use? If I remember correct, I have watched your previous fixing video, right?

DJI Susan Posted at 2018-5-14 01:28
Hi there, may I know how many drones do you use? If I remember correct, I have watched your previous fixing video, right?

Yes, I made one video earlier regarding the fix. How many drones do I own? Too many according to my wife. I own three Tarot's, two Phantom 3s, and a couple of Syma's.

photojunky Posted at 2018-5-14 05:11
Yes, I made one video earlier regarding the fix. How many drones do I own? Too many according to my wife. I own three Tarot's, two Phantom 3s, and a couple of Syma's.

Hahaha, no matter how does she complain, you still have so many drones.

photojunky Posted at 2018-5-14 05:11
Yes, I made one video earlier regarding the fix. How many drones do I own? Too many according to my wife. I own three Tarot's, two Phantom 3s, and a couple of Syma's.

Buy yourself some of the 3-D printed motor reinforcements. I have repaired a lot of these without replacing the lower shell. I take the reinforcements, and before bolting them onto the Phantom, mix up some 2-part epoxy or your Gorilla glue, and lightly coat the inside of them. Bolt them on and wipe off the excess. Totally stiffens up the entire arm. Of course now you committed to leave those on since they a glued! LOL But it will keep the cracks from going any farther and repairs them at the same time. Cheap fix. and yes it is a common problem. I install these now even when I am replacing the lower shell for someone. I insist on it.
Some claim they have never had any issues, and I'm not saying they aren't being truthful, but I have had them myself on several of my own, and numerous friends of mine have had them. It is annoying but after I started addressing them the way I explained, the problem went away. That's my 2-cents. Good luck.

Would be interesting to see a map of where folks fly that have succumbed to this cracking lark, im wondering if there is any UV damage thats aiding this cracking issue?

Bashy Posted at 2018-5-18 20:29
Would be interesting to see a map of where folks fly that have succumbed to this cracking lark, im wondering if there is any UV damage thats aiding this cracking issue?

I doubt it, and I don't believe it is necessarily flying agressively either. I think it is simply poor injection moulding practice. I have experienced it myself with product moulded in China.

I wonder if improper tightening technique causes stress cracks. Most likely, people will grab the entire drone arm and motor when tightening props. I think the best technique would be using the DJI supplied motor armature wrench. Hold only the motor armature while tightening the props or grasping only the motor armature with fingers while tightening the props. Keep your big meat paws off the drone arms plastic. Place the drone on a flat surface and then tighten or loosen the props.

RicardoGray Posted at 2018-5-18 06:25
Buy yourself some of the 3-D printed motor reinforcements. I have repaired a lot of these without replacing the lower shell. I take the reinforcements, and before bolting them onto the Phantom, mix up some 2-part epoxy or your Gorilla glue, and lightly coat the inside of them. Bolt them on and wipe off the excess. Totally stiffens up the entire arm. Of course now you committed to leave those on since they a glued! LOL But it will keep the cracks from going any farther and repairs them at the same time. Cheap fix. and yes it is a common problem. I install these now even when I am replacing the lower shell for someone. I insist on it.
Some claim they have never had any issues, and I'm not saying they aren't being truthful, but I have had them myself on several of my own, and numerous friends of mine have had them. It is annoying but after I started addressing them the way I explained, the problem went away. That's my 2-cents. Good luck.

I had planned on doing that as a last resort. I just did another light layer of epoxy covering all of the cracks. I will fly a couple more hours and see if the cracks continuou. If they do, I will do exactly what you suggested.

I have/ had similar cracking on two Phantoms. (P3/4K and P3 Pro)

I killed the cracks using a mini torch to heat a needle point and pierced the end of the cracks.
I followed with heating the blunt end of the needle and used it to ‘stitch fuse’ the length of the crack.
Note that this stitching was done ‘gently’ and did not pierce the shell. This stitching was done a couple of mm at a time along the shell surface.
This prevented any burn through the shell.  I used a fine diamond nail file to take off any high points on the stitches.
Next came a fine dab of flexible plastic epoxy* along the stitch weld. I used a heavier needle as an applicator to place the resin accurately and more cleanly.
Last came the motor support base plates. These remove some if not all of the pressure from the motor screws.
(MANNOL Epoxy-Plastic 9904)* bought online.

One thing I have not seen considered is the motor screw mounts being out of alignment in the shell. This would put unequal pressure on the shell engine mounts when the motor screws were torqued. Try a little demo using coins. Stack any coin on a set of 4 the same size. The top coin will not rock.
Now substitute one bottom coin with a thinner one. The top coin will now rock. Obviously when applied to a motor mount, the plastic will flex to take up this slack. Hence cracking caused by the stress.
I feel that this is a major contributor to the rash of cracked shells.

So far everything looks fine. BTW, like the OP I had only about 6/7 hours of gentle (careful learner) flying. I was less than inspired to send these new Phantoms in for repair only to be replaced with second rate used, possibly crashed machines.

Anyway, here’s  hoping for some good flying time. Cheers all.