Stress cracks and epoxy

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I saw a few posts about the stress cracks. Well I have a few minor ones on the motor screws. DJI only has a few flights with no crashes. Anyways, I pulled the housing and ordered carbon fiber/kevlar material and will cut into small 1/4" hairs. Do I need to reinforce the long screw shaft on the other side of the light, or is it just the motor housing area? Do I need to do top and bottom of the shell as well, or just the bottom shell piece? Thanks.
 
I saw a few posts about the stress cracks. Well I have a few minor ones on the motor screws. DJI only has a few flights with no crashes. Anyways, I pulled the housing and ordered carbon fiber/kevlar material and will cut into small 1/4" hairs. Do I need to reinforce the long screw shaft on the other side of the light, or is it just the motor housing area? Do I need to do top and bottom of the shell as well, or just the bottom shell piece? Thanks.
Sometimes the bottom of the shaft where the motor mount screws seat, breaks out leaving nothing to hold the motor to the bottom frame at that screw. Just like a loose lug nut on a car, the other mounts quickly follow leaving a free flying motor. I'm not sure beefing up around the plastic shaft will keep the bottom of the shaft from breaking out - and you can't reinforce where the screws seat without changing the motor height on one side or changing the screw length after you thicken the screw seat area inside the shaft.
For me, the easiest method - which has lasted a year now - was to add StrongArm reinforcement plates over the motor mount shafts below the motors. They come with new longer screws needed for the job. Nothing needs to come apart for installation. I couldn't be happier.
 
Why not just send it to DJI to have it replaced under warranty? It's free and will only take a week or so.
Why take it apart and void the warranty if any other issue occurs?
I wouldn't want to pay $1000.00 for something and then have to rig it up and piece it together. The cracks will just reappear somewhere else.
 
Why not just send it to DJI to have it replaced under warranty? It's free and will only take a week or so.
Why take it apart and void the warranty if any other issue occurs?
I wouldn't want to pay $1000.00 for something and then have to rig it up and piece it together. The cracks will just reappear somewhere else.
Warranty, if applicable should be everyone's first choice. Dji has always covered cracks if they weren't crash related, although their latest policy reads "no warranty for the airframe." After-Sales Service Policies - DJI
 
Sometimes the bottom of the shaft where the motor mount screws seat, breaks out leaving nothing to hold the motor to the bottom frame at that screw. Just like a loose lug nut on a car, the other mounts quickly follow leaving a free flying motor. I'm not sure beefing up around the plastic shaft will keep the bottom of the shaft from breaking out - and you can't reinforce where the screws seat without changing the motor height on one side or changing the screw length after you thicken the screw seat area inside the shaft.
For me, the easiest method - which has lasted a year now - was to add StrongArm reinforcement plates over the motor mount shafts below the motors. They come with new longer screws needed for the job. Nothing needs to come apart for installation. I couldn't be happier.
Did you install the StrongArm plates to fix a break or as preventative measure?
 
Did you install the StrongArm plates to fix a break or as preventative measure?
I had a crash that actually bent the motor end of a rear arm bad enough that the prop hit the shell when turning. I straightened the arm with a heat gun. After all that there were still no visible cracks, but I added the StrongArms for extra support. Still no problems a year later. Lucky I guess.

And PS: I try to fly every day it isn't too cold or windy. (which it is right now in Colorado)
 
Warranty, if applicable should be everyone's first choice. Dji has always covered cracks if they weren't crash related, although their latest policy reads "no warranty for the airframe." After-Sales Service Policies - DJI
I don't see anything there saying "no warranty for the airframe"
Besides, what is an airframe? DJI calls it a body or shell.
I sent mine in a short time ago, they fixed it no questions asked. The same with the controller. The inside plastic started falling apart and the RTH button was falling inside.
 
I don't see anything there saying "no warranty for the airframe"
Besides, what is an airframe? DJI calls it a body or shell.
I sent mine in a short time ago, they fixed it no questions asked. The same with the controller. The inside plastic started falling apart and the RTH button was falling inside.
Shell, frame and body are all the same.
Yes I understand they have provided warranty for shell/frame problems. I just looked up their official warranty policy and provided the link. They do not offer (officially) warranty for the frame/shell on their consumer P3 models, but I'm glad they do consider it on a case by case basis. I do believe that spontaneous shell cracks are a manufacturing defect. How else could it be described?
 
Shell, frame and body are all the same.
Yes I understand they have provided warranty for shell/frame problems. I just looked up their official warranty policy and provided the link. They do not offer (officially) warranty for the frame/shell on their consumer P3 models, but I'm glad they do consider it on a case by case basis. I do believe that spontaneous shell cracks are a manufacturing defect. How else could it be described?
Would you recommend installing the StrongArm plates on a new P3 or wait until something happens (like a crack or a crash)?
 
I can't see how the reinforcement plates could be much help in a crash, but they absolutely beef up the known weak points in the plastic under the motors and should keep that area in tact. They weigh next to nothing, won't interfere with the aerodynamics, are very easy to install and inexpensive.
So yes, I would install them as soon as possible in the hope they will prevent or stop cracking under the motors. If there is a warranty along the way, just remove them before you send it in. (10 minutes)
 
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I can't see how the reinforcement plates could be much help in a crash, but they absolutely beef up the known weak points in the plastic under the motors and should keep that area in tact. They weigh next to nothing, won't interfere with the aerodynamics, are very easy to install and inexpensive.
So yes, I would install them as soon as possible in the hope they will prevent or stop cracking under the motors. If there is a warranty along the way, just remove them before you send it in. (10 minutes)

Agreed [emoji121]️. I have been using the Strong Arms from Infinity hobby for almost a year now, no cracks. There are a lot of different Strong Arm plates on the market, some are Aluminum and some are Plastic, The ones I have or aluminum made by infinity hobby. If you do your research you will find that the aluminum ones on the market are just a little different depending on the manufacturer. IMOP the ones from Infinity Hobby are very well made and easy to install, and look good as well..
 
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Agreed [emoji121]️. I have been using the Strong Arms from Infinity hobby for almost a year now, no cracks. There are a lot of different Strong Arm plates on the market, some are Aluminum and some are Plastic, The ones I have or aluminum made by infinity hobby. If you do your research you will find that the aluminum ones on the market are just a little different depending on the manufacturer. IMOP the ones from Infinity Hobby are very well made and easy to install, and look good as well..
As far as I am aware these are now out of stock permanently.
 
Thanks. Used carbon fiber/kevlar 1/4" strands. Came out nice. Just waiting for the resin to harden.
 
Thanks. Used carbon fiber/kevlar 1/4" strands. Came out nice. Just waiting for the resin to harden.
Did you cover the spots where the motors sit on the end of the lower plastic shafts that the screw heads must seat and keep the motors from breaking loose? That's the area that really concerns me.
If the end of the shaft breaks through (and it's very thin) there is nothing else to hold the motor.
 
Yes, but I went up to the small ridge around each shaft. No further. The area directly below the motor has a thin coating of resin and carbon/kevlar strands.
 
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Hello,

My phantom 4 is close to year old and i have a stress crack and need to know if it effects the motor mounting?
See pic attached

Regards
 

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