Catastrophic design flaw of Phantom 3
- Thread starter Chris Vedeler
- Start date
Fairly new P3 here and I have 4 screw hole (not the 2 hole kind) prop guards on - maybe 30 practice flights around home. Reading these treads about stress cracks made me start looking at mine. I haven't unscrewed prop guards to look underneath yet bet I do see one crack in one of the inner screw holes already - UGH! Hopefully not as bad yet as some, but will see after guard removal.
Choices?
Call vender on Monday...
Call DJI om Monday...
I really don't want to send her back but.... Will see...
What type of plastic is this shell made from? Poly?........? Or ?
Question for someone that knows plastics. If I decide to remove top shell and fill (reinforce) the motor mounts and screw hubs where crack is. What would be BEST to use?
Hot glue like above? or some kind of plastic epoxy? If epoxy, what would be the ultimate brand and type to use, to fill the motor mount area up to top of screw hubs. Would this be a bad idea? Fill all 4 the same for weight balance etc...
I would then put prop guard mounts back on as they are the quick removal guards and the guard mounts can stay on.
Opinions please!
Sorry, but my OCD won't let me fly again until I am SURE I did all I can to prevent what has happened to others over stress cracks etc...
It is bad enough, that I am nervous over everything else that could happen to my baby.
Thanks.
I used Bondic and that has stopped the cracking. The shell is made of thermoplastic and the current most plausible theory is that the increased power of the motors combined with the active breaking components heats up the arms enough to cause brittling in the plastic and cracking over time. This was most likely limited to the early batches of P3s in the market and was the molding formula was adjusted after this became aware on user forums in early July. Mine started only on one arm about 100 flights in and has ceased to be an issue to me if it makes you feel any better. The guy whose motor ripped right out without warning was in 100+ temperatures so YMMV.
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Not really familiar with Bondic - I see it IS heat resistant - is it best used for just cracks, like welding or can it be applied as a filler like epoxy? I was hoping to find a heat resistant plastic epoxy and fill around all for motor mounts (along with my 4 screw prop guard mounts) to try and future proof it for this crack BS...
Is Bondic less used as an adhesive than epoxy?
Did you just use the Bondic along the existing cracks or fill all around?
Just the existing cracks. I had no desire to open the shell as I have done so many times on P2s installing FPV cables, etc.
Found a couple of tiny stress cracks starting on one of my rear arms near a motor screw. Didn't want to mess with waiting 2+ months for DJI to hold my quad captive (its prime flying season!)
So, I designed my own version of a motor mount and arm support and 3D printed a set for my P3P. They only weigh 2.32 grams each but they are super strong, cant break them with my bare hands.
So, I designed my own version of a motor mount and arm support and 3D printed a set for my P3P. They only weigh 2.32 grams each but they are super strong, cant break them with my bare hands.
Have not had to do this yet on this stage ! although very familiar with welding. I had a cracked landing gear leg and purchased jb weld epoxy(for plastic) for that application. Took a small file and ground in just short of root of crack .Cleaned it very well with an all purpose cleaner and applied the epoxy with tooth pick into that area. Strong as an ox. How ever if u are looking to reinforce an area that is not showing signs of stress I would leave it alone. Just my opinion.
Found a couple of tiny stress cracks starting on one of my rear arms near a motor screw. Didn't want to mess with waiting 2+ months for DJI to hold my quad captive (its prime flying season!)
So, I designed my own version of a motor mount and arm support and 3D printed a set for my P3P. They only weigh 2.32 grams each but they are super strong, cant break them with my bare hands.
Great Idea, let me know how that works out.
People with "OCD" shouldn't buy Phantom 3's LOL!
I put these on within a week of buying my P3P - red front for orientation:
Then this 2 piece gimbal/ribbon cable protector:
Then I had to have a gimbal guard - had to modify so there was clearance for camera with new 2 pc protector:
Then:
Ugh! Now "StressCrackGate" I found only one after removing prop guard mounts and inspected thoroughly:
View attachment 30578
OK I read to much - worry too much - now this:
Somebody stop me!!!! LOL! Maybe I shouldn't fly it and just set it on the mantel to look at...
Nice expensive conversation piece
haha. you got OCD real bad man! I had quite a few bad crashes from using those prop guards on my Ph2s when it descended in go home mode and the extra weight was enough to make it toilet bowl and then become unrecoverable. I am always nervous about them now. However since then DJI did replace my smashed up gimbal under warranty and they had since reduced the decent speeds. I would also be very careful to over weight it more than its deign spec which seems you have a few add on there,. It can affect the flight and in particulate on descents. Sorry to feed your ODC , but just a point to be aware of
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Found a couple of tiny stress cracks starting on one of my rear arms near a motor screw. Didn't want to mess with waiting 2+ months for DJI to hold my quad captive (its prime flying season!)
So, I designed my own version of a motor mount and arm support and 3D printed a set for my P3P. They only weigh 2.32 grams each but they are super strong, cant break them with my bare hands.
Have a version of these to support prop guards with 4 screw holes (not 2 hole version)?
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Not as bad as I used to be when younger "OCD" LOL! Just that it can make any new person flying $1300+ a bit nervous about flushing it
I flew it with and without guards and didn't notice any major difference myself, but I am a fairly new pilot.
And COM'ON.... Didn't you ever go back to check to see if you locked the door? Or turned around to make sure you closed the garage door? Just kidding
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Will you be selling these? I like how the design seats down in the hole. Will need to see what kind of changes DJI made when I get my bird back but these look nice.Found a couple of tiny stress cracks starting on one of my rear arms near a motor screw. Didn't want to mess with waiting 2+ months for DJI to hold my quad captive (its prime flying season!)
So, I designed my own version of a motor mount and arm support and 3D printed a set for my P3P. They only weigh 2.32 grams each but they are super strong, cant break them with my bare hands.
Yes, I have had a few people say they are interested in buying a set so I printed up some extras, bought some more hardware put up an eBay auction. I have about 10 sets in hand and ready to ship right now.
Thanks!
Link to eBay listing:
DJI Phantom 3 Motor Mount Stress Crack Fix Support 3D Printed w/ hardware
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Yes I got it to don't worry about that, I am sure everyone does to some extent. I hate dirty hands and coffee grinds in the bottom of the sink to mention a few.Not as bad as I used to be when younger "OCD" LOL! Just that it can make any new person flying $1300+ a bit nervous about flushing it
I flew it with and without guards and didn't notice any major difference myself, but I am a fairly new pilot.
And COM'ON.... Didn't you ever go back to check to see if you locked the door? Or turned around to make sure you closed the garage door? Just kidding
Its mostly noticeable if you descend to fast. But these Ph3s have different motors now so it may not happen on the Ph3 so easily. However in saying that I did notice my Ph3 just starting to do the first funny wobbles when I descended quite quickly the same type of wobbles my Ph2s would do before going to crap. Its caused when the props are coming down into their own downward prop wash. So just watch it on the fast descents mostly.
UAVBits.net sells the "strong arm" kits which are basically the same thing, I think they were $25 for the set. I had over 35 flights with no cracks or anything...then I bought these stupid "PhantomGuard" prop guards from the DJI retailer near me. Within 2 flights they had cracks, I explained to the guy at the DJI store that as soon as I put those ******* guards on, it started wobbling really bad during descent. It didn't spin or "toilet bowl" but it wobbled a lot!! I know it was those stupid ******* guards that caused the cracks, but DJI store (Drones Plus, in Santa Clara, CA) said it was a "non-issue", and that they tried the guards themselves and saw no wobbling. Ohhh, so I'm ******* blind now??? I know what I saw...anyways, they charged me for the new shell ($65) and the labor ($85). I won't be buying much else there...and on top of everything, they made me wait an extra week to get it back because their store got ROBBED two days after I dropped my P3P off for repair!!!
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Hitting a brick wall? It did with my P2V. 
Seriously though, it could still be related to the motor mounts. What's the underside look like? The location of those fractures are exactly where the two screws holding that portion of the shell together are.Not the motor mounts. On the underside you'll see the four screws for the motor and then the two for the shell. I'm keeping an eye on my new P3A for any signs of stress.
Seriously though, it could still be related to the motor mounts. What's the underside look like? The location of those fractures are exactly where the two screws holding that portion of the shell together are.Not the motor mounts. On the underside you'll see the four screws for the motor and then the two for the shell. I'm keeping an eye on my new P3A for any signs of stress.
ianwood
Taco Wrangler
I have numerous cracks on all my Phantoms. None have had this type of structural failure. This is the only case I have seen. Unless you crash hard, you probably won't have issues.
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