Stress fractures... A theory

[storrowdrive]

I'll say this isn't a good theory.

Almost all of the P3's with cracked shells is the inside screws on the rear arms. I think they are over tightening the screws at the factory.

My cracks were on the rear arms as well. I get the blade balancing theory but in my opinion the culprit is the combination of the stronger motors on the P3 and the arms that are not designed to be able to handle the extra torque. I think most of the cracks being on the rear arms supports this even more because most of the time you are moving forward and those two rear motors are pulling up constantly more often than the other combinations of motors.

 

[skyhighdiver]

How have you found the factory props? Balanced or off enough to make a difference?

I have found on both my p2 and p3 that the black hub props are usually spot on but the silver ones are off just alittle a simple piece of tape on the lite side does the trick I think DJI needs to check the silver mold but as stated it is ever so slight

 

[envisionabove]

1. Pilots that diligently make sure the props are balanced are they reporting cracks?
2. Pilots that did not balance and flew with clean props are they reporting?
3. Truthfully - Have you flown with chipped or slightly damaged Props? Are you reporting cracks? ( We only had two sets to start with for a while. )
4. Have similar problems with P2's been reported over time? ( The shells are very similar are they not? )
5. Did you get a first release P3 and whats the percentage of the P3A and P3P reports.

Now I have flown with chipped Props, No balance check I have a crack in one arm only, I had two minor crashes as a newbie.

Some have said they come out of the box with cracks? But with so many false reports from those that want to trash the P3 data could be wrong.
Honest answers are the only way this problem will be zeroed in on.

 

[ianwood]

P3 props are pretty well balanced. Not perfect but good enough. P2 props are the same for the most part and the P2 doesn't have a huge crack problem like the P3.

I think the P3 puts more stress on the frame as result of a more aggressive FC including active braking. The canted motors are probably contributing to the additional loading as well.

 

[BenDronePilot]

P3 props are pretty well balanced. Not perfect but good enough. P2 props are the same for the most part and the P2 doesn't have a huge crack problem like the P3.

I think the P3 puts more stress on the frame as result of a more aggressive FC including active braking. The canted motors are probably contributing to the additional loading as well.

Between the better mortors, ESCs and 4S battery the P3 generates much more torque on a similar air frame as the P2. So you never know.. all that extra torque.. in addition to people taking extra steps to tighten their props on might very well be a conributing factor to the problem. I personally have never seen stress cracks on either of my P2 Visions. I'll have to wait and see how things go on my Phantom 3 when it arrives and I've put some hours on it.

 

[ScottyT]

My cracks were on the rear arms as well. I get the blade balancing theory but in my opinion the culprit is the combination of the stronger motors on the P3 and the arms that are not designed to be able to handle the extra torque. I think most of the cracks being on the rear arms supports this even more because most of the time you are moving forward and those two rear motors are pulling up constantly more often than the other combinations of motors.

Mine are in the rear arm screws too and I agree that the predominant forward motion would likely put more stress on those arms. Will probably go the epoxy & cable ties route.

Does anyone know if you can get to those inside screw standoffs by simply taking the motors out, or would I need to take the top off?

 

[BenDronePilot]

Mine are in the rear arm screws too and I agree that the predominant forward motion would likely put more stress on those arms. Will probably go the epoxy & cable ties route.

Does anyone know if you can get to those inside screw standoffs by simply taking the motors out, or would I need to take the top off?

If you wanted to take a pre-emptive step to stress cracks one thing you could do is applying a strong epoxy glue to the inside of the holes on the inside of the body shell. You would first want to scuff the plastic a bit with sand paper.. than apply an even coat of epoxy around the circumference.. of course you need to have the body shell off for this.. Alternatively you could do it from the outisde with the bodyshell on though it may not adhere as well. If i wanted to do a strong reinforcement I personally would do it from the inside.