Yet another cracked shell

[Apilot101]

Yes once fixed, add braces. I feel that this is 1 of the best upgrades on the P3.

 

[Tim Dawes]

If one uses the metal external braces be very careful not to overtighten or they will induce a crack!

 

[Satellite Aerial View]

Hi redlegs, there is some good advice here regarding your shell crack problem. I have a P3A and P3P the Advance I have had for 4 years and the Pro only about a year. the Advance also had cracks which I fixed and will explain shortly. When I bought the Pro I found one crack already out of the box but decided to cop it. DJI knows they have this problem with the 3 models and they were prepared to replace the shell on the Pro but it would have taken 6 months which was unacceptable to me. I decided to fix it (the same way as I did with the Advance) I cut into the crack with a small "V" shape and then use a special bond it's called Rapid Fix made in the US it works very well and I have used it on the Advance for 4 years with no problems. Rapid Fix comes in a small bottle and then you use a Ultra Violet light (which comes with it) on the glue and it cures it. I also use base metal supports screwed under the motors and it fixes the cracking problems for good (do not use the plastic ones as they still crack which I used and replaced). I still keep an eye on the shell and regular inspection with the Ultra Violet light it shows any cracks better than a standard torch Ultra Violet light is also used on commercial aircraft undercarriage for cracks in the struts.
In conclusion I think that if the shell was replaced by DJI the problem would still appear as it is a design fault so you would be back to square one. I hope this has been of help.
Cheers, John

 

[Bigskyflyer]

That's not normal .... something going on there ....

Cracks are normally in the bottom shell emanating from motor screw holes. If cracks appear in the actual arms or body - usually that crash or impact damage.

I would be reluctant to try repairs with the cracks as you show ... who knows what else is 'under the skin' waiting to give ?

I think this is a replace shell matter ... IMHO.

Nigel

By the looks of the location of those cracks it looks like those 2 screws next to the motor screws were tightened way too tight.

 

[solentlife]

By the looks of the location of those cracks it looks like those 2 screws next to the motor screws were tightened way too tight.

Could be for the outer arm cracks ... pulling and deforming the top shell ....

But the cracks at base of legs would possibly be from landing out hard / angled ?

Anyway - all are repairable ...

Nigel

 

[Satellite Aerial View]

Hi solentlife, I think your correct the cracks at the top of the legs are from hard landings.
When I get a new drone the first thing I do (besides other things) I check all the screws on the drone and I find a lot are
loose so all get tightened specially the ones around the motor (not over tight). If any screws are loose on the shell
arm it can cause twisting and that is how you get cracks there. I have also been told that the cracks around the motors
can be caused by sudden in flight stopping from high speed. One final tip: to stop any screw from loosening again
after I have tightened them is I use one small drop of Super Glue on the tread of the screw and that works very well
for me, after 4 years none have loosened and I still do regular checks.
Cheers, John

 

[tom3holer]

On a side note does anyone balance the props?
I wonder if this could be an issue?
Tom

 

[Steve_in_DE]

My P3A developed two stress cracks on one arm, one on each shell. Due to that incident I have learned about, and have become a fan of, the "baking soda and superglue" fix. There are a bunch of youtube videos describing this - have a look. I have flown my bird several miles since the fix - so far so good.

 

[Tbonham27]

Over 30 flights on repair. Gorilla hot glue stick. Go ahead...let me have it.

 

[Tbonham27]

Hopefully this is not looked on as hijacking his post but it's shell related....will my gimble amputee phantom 3 shell interchange with my busted arm p3a? Need.mods? Even possible?

 

[AirPatrol1]

I replaced a shell and it does take some patience and if you can do the fill in crack routine it is easier and even with a new shell cracks will surface again. Don’t know why DJI continues to make these weak plastic shells but if they didn’t crack they couldn’t sell shells.

 

[solentlife]

Hi solentlife, I think your correct the cracks at the top of the legs are from hard landings.
When I get a new drone the first thing I do (besides other things) I check all the screws on the drone and I find a lot are
loose so all get tightened specially the ones around the motor (not over tight). If any screws are loose on the shell
arm it can cause twisting and that is how you get cracks there. I have also been told that the cracks around the motors
can be caused by sudden in flight stopping from high speed. One final tip: to stop any screw from loosening again
after I have tightened them is I use one small drop of Super Glue on the tread of the screw and that works very well
for me, after 4 years none have loosened and I still do regular checks.
Cheers, John

Late reply ... I would suggest to NOT use Super Glue (CA) on the screws ...

Best is BLUE Plastic Safe Thread Lock ..... if you look at screws applied by factory - you will see the tell tale blue ring in the thread.

Nigel

 

[solentlife]

Something to ponder :

It is poor engineering to stiffen up an item if the stress cannot be channeled out safely. Best is to ease in the stiffening so the stress is distributed.
Applying CA / Soda fixes are fin - but any CA joint / fix tends to create a hard line.

Nigel

 

[Aussie markD1969]

Dang IT....for one epoxy won't work for plastic......Their is a 2 part plastic weld that you can buy at a auto parts store....lightly sand paper the area of the crack and apply the plastic weld to the cracked area..I'm sure more Great Advice will follow ! ...You can buy a new body off Amazon or E_bay....thats a lots of work to do the swap over....So go the plastic weld solution first ! Good Luck and let us know how your doing and send pictures of the before repair and after repairs !

Oh and IF you can lay in a strip of fiberglass after a lite smear of plastic weld the length of the cracks..then dab some plastic weld over it !..that will sure make that area much much stronger

This is the product

 

[joeyjan19]

I have a P3P that has developed several cracks in the shell. I am new to the drone world and have been very paranoid about damaging the unit because of flying too rough, so I have been very careful with it. I check for cracks before and after each flight. I went from having zero noticeable cracks in the shell yesterday, to having several cracks in the shell today after about 35 minutes of flight time. My unit is not under warranty. So, what should I do? Should I try to use an epoxy of some sort to try to repair it? Should I get a replacement shell and try to replace it myself? Or should I send it off for a replacement?

By any chance do you have a torque wrench that you can check the screws in the area around the cracks. This could give us a idea of what is “ to tight” and what is causing or contributing to these cracks.

 

[Aussie markD1969]

Seriously, just don’t go crazy there only tiny screws and the Loctite or glue will hold them no worries at all ..

 

[joeyjan19]

Seriously, just don’t go crazy there only tiny screws and the Loctite or glue will hold them no worries at all ..

No, I am questioning if the drones are coming from the DJI with the screws over torqued. If so, this is causing the start of the crack from the vibration of the motors. If we can get some idea of what is over tightening from the factory, if this is the problem, simply loosen and torque the screws to the correct setting would be a simple fix.

 

[solentlife]

And who's going out to buy Torque Drivers ?

Nigel

 

[RodPad]

I had kind of wondered a few times about torque stuff for small items, including Phantoms. I assume they must exist.
I'm sure in industry such as this, these units are assembled with calibrated instruments.
Somebody needs to leak some Photos / Footage.

Rod

 

[joeyjan19]

And who's going out to buy Torque Drivers ?

Nigel

OH...PLEASE,You spent a thousand dollars on a drone,a couple hundred on extra batteries and God only how much more on other drone stuff and you can’t cone up with $20.00 US for a small torque wrench. Sorry I think it’s about $22.00 on AMAZON and no PHD required to use.