Motor reinforcement plate is not enough.

LOOSEN SCREWS
I fixed UAV reinforcements 6 weeks ago.
I decided to check my sheel against cracks last day. What I observed is screws are (4 motor) loosen on each arm. You can even turn the screw with a little touch with screwdriver. I don't know why? I'm pretty sure that I tightened them very well.
You better to check yours.
 
LOOSEN SCREWS
I fixed UAV reinforcements 6 weeks ago.
I decided to check my sheel against cracks last day. What I observed is screws are (4 motor) loosen on each arm. You can even turn the screw with a little touch with screwdriver. I don't know why? I'm pretty sure that I tightened them very well.
You better to check yours.
You may use nail polish as a screw locker.
 
Zoti was using his own design, not the UAV Bits designed Strong Arm. We have not had any customers report new cracks or further cracking under our Strong Arm Reinforcement Plate. Our patented design couples all six screws to spread the forces out over a large area. The Strong Arm will be available in a more rigid material soon and a completely new design that makes the arms rock solid.
View attachment 31841
I will be posting an installation video on how to bed the Strong Arm for those that want a completely flush fit and maximum strength from the Strong Arm. I should have the new video up by Monday.
Great. My strong arm arrived yesterday in New Zealand. $25 for the bits, same for freight. $50!
Now I find out I could have waited a short while and had a "completely new design that makes the arms rock solid."
And no hex keys included. I've been more impressed in my life.
Note to vendor: I suggest you tell people a new version is about to come out and offer them the chance to wait and get it.
 
Great. My strong arm arrived yesterday in New Zealand. $25 for the bits, same for freight. $50!
Now I find out I could have waited a short while and had a "completely new design that makes the arms rock solid."
And no hex keys included. I've been more impressed in my life.
Note to vendor: I suggest you tell people a new version is about to come out and offer them the chance to wait and get it.

I just got mine as well and haven't even installed them yet. Frustrating.
 
unless the plates fit 101% perfect i really cant see how they help, surely they must also be bonded to the shell to provide any sort of strength ?
That's what I was thinking. I bought the "StrongArm" plates kit, but haven't installed them yet (I'm not seeing any cracks yet, either). I've been thinking that the only way they could really work would be to bond them to the shell, before putting the screws in, then the screws would help clamp them in place while the adhesive cures, essentially making the arm end equal to "thicker plastic."
 
Great. My strong arm arrived yesterday in New Zealand. $25 for the bits, same for freight. $50!
Now I find out I could have waited a short while and had a "completely new design that makes the arms rock solid."
And no hex keys included. I've been more impressed in my life.
Note to vendor: I suggest you tell people a new version is about to come out and offer them the chance to wait and get it.

Why would they do that and have to throw out all their stock - and that which may or may not be in dealers stores.But thanks for the heads up about the upgrade...
 
Personally I am eager to see what the difference is. I shelled out for the more expensive shapeways version but if the new design is that much better may be down for a set. I doubt they will completely invalidate the current design. $50 is a pretty minor cost give the hobby. Limited life items like batteries run 3 times as much.
 
Why would they do that and have to throw out all their stock - and that which may or may not be in dealers stores.But thanks for the heads up about the upgrade...
They're 3d printed so I'm guessing there's limited stock to get rid of. But I'd just like to have had the choice.
I suspect enough people would have taken the current version; personally I would have waited.
 
I am on your side -
Following the latest threads and posts - I decided that the "strong arm" type of bodge ups - do not really help - they may delay but without some form of bonding to cement two surfaces of thin plastic ( poly) into one solid piece... the main arm support is still subject to the stresses created by the motor through the screws and heat the motor generates. I am no aeronautical engineer but it just seems common sense. Unless both surfaces are machined to fit without any space between them - they will act independently - granted there will be an amount of "grip" between two surfaces - but not enough to prevent the top plate vibrating.
I also think part of the problem is... nobody want to lock the screws permanently, so blue loctite or nail varnish is a bit like adding passengers in a car ( auto)( vee-hi-cul) the added loading may slow it a little but it still moves !
The real solution is for DJI to redesign the motor arm structure. I would suggest that as they have some very useful 450/500 frames the use the arms from them, or even rebuild the phantom on a stronger frame and wrap a skin around it!
 
I received the Strong Arm backpack plates last week and installed them yesterday. I haven't experienced any cracks, yet. And hopefully I won't experience any. Really, I see the Strong Arm plates as insurance to prevent a motor from flying off, should a catastrophic crack develop in flight. For the same reason, I have a gimbal protector.
 
I agree that bonding them would provide the most reinforcement but would void the chance of a warranty replacement if cracks develop. After a couple of flights these things seat really well and the combination of friction between the parts and the spread of force across the strong arm should help.

As said before it's a cheap option to give you a chance to save it if the motor comes loose. Not saying it would give you complete stability but you may have a chance to land.
 
nothing to report after a hundred flights. As an experienced RC pilot, I have seen too many P3 flyers keep flying even when the props are way out of balance ...


It's because you're a pro obviously lol
 
Ok... I gave up and ordered the UAV strong arm.

I have been aware of cracks since the P2 range and loosen and re-torqued my screws from day 1. Spring is here and I cant afford the 2 month wait so I took matters into my own hands.
My phantom has had 3hrs of flights, no crashes and always hand caught. Majority of the flight was in cooler winter climates. The cracks I have are motor mount related. The 2 shell mounts are still good and has no signs of cracking.

Being a hobbyist, I did some tinkering and preventative measures to minimise the cracks. I used cable ties on the end of the arms to make it more rigid and I used hot glue gun to reinforce the plastic - worked on the P2 but doesn't work on the P3. I did a few more flights and more cracks started to show. Some cracks are invisible and require closer inspection. I found mine by licking my thumb and rubbing the plastic. If it shows up black, it means you need to inspect and its most likely a crack. If the crack joins from screw hole to screw hole, then there is a high chance of catastrophic failure.

Fracture%20fix.jpeg


It takes 1-2 months for the UAV bits to arrive. For now, I made some temporary brackets to stop the motors from total separation. The brackets are mounted on the vertical screws as these have the same camber and depth of thread.

20151001_112108.jpg


After messing around, its come to my conclusion that the shells are using a poor plastic compound. It is possible that DJI has used other parties/contractors to manufacture the shells and never quality controlled.

The only thing I will hate is that DJI will be making a **** load when they release a revised non-cracked replacement shell. There will be end-users like myself who can't afford to lose 2 months of seasonal downtime and have to resort to voiding the warranty and paying full fare for a new shell because of a fundamental design fault.
 
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Not sure if this is necessarily a fix for the cracks. Really seems that they are working the newer propulsion system motors into the phantom line. There is supposed to be a reduction in cogging with these which may help reduce wear on the chassis but I doubt this was specific for the cracks.
 
DJI approved my repair at no cost to me. Now let's see how long it takes.
 
And I just got an email saying my unit is on its way back to me.
 

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