I experienced a catastrophic failure to my P3P this morning. Essentially one of the motors of my bird sheared off in flight. I don't think most people realize exactly how the motors are attached (I know I didn't). All that repeated torque, thrust and force of these powerful motors is transferred to a thin layer of plastic less than 1mm thick (see the picture). Who designed this? Plastic will fatigue, crack and soften with heat (the motors can get very hot). Failure was inevitable.
There have been many posts here regarding cracks of the plastic around the motor mounts. When I read them, I inspected my P3 I assumed that since I did not have cracks when I checked two months ago, that I was safe. I wish I had checked before my flight this morning as I would bet I had cracks that had developed.
I would bet that ALL Phantom 3s will eventually have this problem. If you are flying where it is hot like me, I would bet you will have this problem sooner rather than later.
This is now standard issue for my future Phantom's:
Strong Arm reinforcement plate
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I've thought about the Strong Arm Reinforcement Plate but the bigger issue is the four arms of the Phantom flex in flight, not just where the motor mounts are placed. I'm sure the flexion at the end of the Phantom arms is greater at the tip than at the base of each arm. But I'm thinking each arm needs to be reinforced from the base to the tip with the thickness of each arm increased and of constant thickness from base to tip. I'm also wondering if increasing points of contact for each motor shouldn't be added by not only a motor mount on the bottom of each arm, but also something that goes OVER each motor, like a hard polymer bracket, so that the bottom AND top of each arm provides increased support for each motor and increased restraint from the high torque and thrust of these motors.
Frankly, I think DJI would be wise to have their Phantoms put into a static chamber and run tests involving at the minimum, high speed film footage of what exactly happens when these Phantoms are jerked around repeatedly while in captive flight. Real aircraft experience metal fatigue and after so many flight hours, many parts have to be replaced or risk loss or damage to the aircraft. Why not have the same concept for these Phantoms?
I've seen the flight gyrations people put their Phantoms through and despite them stating they were flying them normally, the video proves otherwise. Or, they've jerked it around in the air so much than on flight number XXX, a calm normal flight, polymer fatigue kicks in and they lose the quadcopter to a catastrophic incident that to them seemed to have nothing to do with what they were doing at that moment... where in the past, all their gyrations precipitated this eventuality.
I'm not saying that's what happened here but there has been talk of a CF (Carbon Fiber) shell in the works and the hazards of that for GPS etc.
Something's gotta give here on the part of DJI in their design, I think they need to hire actual aircraft airframe inspectors and their inspection regimes and determine how best to fix this problem and come up with an add-on kit, free I might add, to help eliminate a very expensive issue.
But keep in mind, the bottom line on DJI's part is these Phantoms were designed for calm hobby flights... that'll be their defense but until they install black boxes on their quads, an authorized inspection regimen after so many hours of flight, and airframe inspections, this problem will continue. More importantly, a lot of people are using these quads for work, not play, and if DJI doesn't embrace this issue, they could face Federal backlash in the form of a class action suit knowing full well people are buying their product when they are fully aware of defects in them... just like automobiles... a two pound quad falling out of the air onto someone's head 200 feet below could cause a death or serious brain injury.
