If the motor mount screws actually make contact with each motor, the metal screws attached to each heat sink then the screws are IN each motor, then heat could transfer through the screws to the heat sink. Yes, the plastic would get warm but would it stay cool enough as to not alter its integrity?
I'll write this one last comment then shut up to see what other people think. I pretty much have not flown much this Summer, it's been awfully hot down here in Florida, with the heat index it's triple digits almost every day except when it rains in which case I can't fly. The few times I HAVE flown this Summer, I could not get over just how hot my Phantoms got and of course my iPad got hot enough to cook an egg on it. Even standing in the shade the iPad just cooked. Even flying my Phantoms around to get air flowing over them didn't decrease the heat they generated; I greatly minimized their hovering for this reason, I just kept them moving, but they kept heating up. I don't know if there truly is a fix for the heat issue, perhaps cooler Fall and Winter weather will greatly reduce these airframe fatigue failures? In Florida, 80 degrees F is a cool day but you guys up North could answer that question better than I.
I realize the exposed portion of each motor turns, that there is no external way to reinforce how they're mounted to each arm of the Phantom. I guess the ideal would be a metal rod running down the length of each arm, securely mounted to each motor, with the existing plastic arm covering it. I'm not thinking this through but using plastic as the primary support mechanism is flawed from the get-go.
The analogy I draw is in regards to firearms... there's a lot of polymer frames and support in Glocks and S&W's and so forth, and its being introduced into long-arms. But in the end, the all-metal ones will out last the polymer ones. Don't argue with me on this particular point, I'm just stating that metal support for each motor makes more sense then plastic. I like the zip tie idea but the motor is still mounted to plastic and could still shear off. The "don't worry, be happy" mentality of one poster really bothers me. It's like he's saying, "When you're on a Boeing 777 and wonder about the upkeep of the aircraft, just say 'dont' worry, be happy, everything's gonna fail someday'... doesn't sit well with me. I can't afford $1300 worth of "don't worry, be happy", I'm not loaded like a lot of posters appear to be.
I realize the exposed portion of each motor turns, that there is no external way to reinforce how they're mounted to each arm of the Phantom. I guess the ideal would be a metal rod running down the length of each arm, securely mounted to each motor, with the existing plastic arm covering it. I'm not thinking this through but using plastic as the primary support mechanism is flawed from the get-go.
The analogy I draw is in regards to firearms... there's a lot of polymer frames and support in Glocks and S&W's and so forth, and its being introduced into long-arms. But in the end, the all-metal ones will out last the polymer ones. Don't argue with me on this particular point, I'm just stating that metal support for each motor makes more sense then plastic. I like the zip tie idea but the motor is still mounted to plastic and could still shear off. The "don't worry, be happy" mentality of one poster really bothers me. It's like he's saying, "When you're on a Boeing 777 and wonder about the upkeep of the aircraft, just say 'dont' worry, be happy, everything's gonna fail someday'... doesn't sit well with me. I can't afford $1300 worth of "don't worry, be happy", I'm not loaded like a lot of posters appear to be.
Hey, Just zip them up and go out and enjoy your quad. Life's too short to worry about things you have very little control over. They will crack if they want to, All you can do is try to hold things together if they do
View attachment 30045
Your little fix will do nothing if it does this and this is exactly what the others look like as well and it matches the Flir image
Catastrophic design flaw of Phantom 3
True, but Chris has admitted that he had a crash early on and didn't open it up to see if there was any damage to the motor mounts at that time. I'm saying the cracks may have been there since the crash and have been getting worse until it finally gave up and broke away. Nothing could have saved it if that was the case, even a stronger shell.
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... or instead of adding reinforcements from plastic or aluminum, we could just drill some holes in the plastic surrounding the motor to provide cooling from the prop wash...
This would also provide structural reinforcement and save weight
Which reminds of the story that in the eighties the Russians had a lot of accidents with their jet airplanes, and could not seem to figure how to get it right. A passer by happened to walk on a frustrated Russian engineer after another plane had crashed at Le Bourget Airshow.
-"What's going on?" he asked.
The Russian engineer retold the story of how the wings were cracking and falling of the airplanes.
-"I know what you should do", said the observer: "Drill holes in the place where the wings attach to the airplane".
-"And that will help?" asked the Russian engineer.
-Well, said the observer: "did you ever see toilet paper tear at the tear holes?"
This would also provide structural reinforcement and save weight
Which reminds of the story that in the eighties the Russians had a lot of accidents with their jet airplanes, and could not seem to figure how to get it right. A passer by happened to walk on a frustrated Russian engineer after another plane had crashed at Le Bourget Airshow.
-"What's going on?" he asked.
The Russian engineer retold the story of how the wings were cracking and falling of the airplanes.
-"I know what you should do", said the observer: "Drill holes in the place where the wings attach to the airplane".
-"And that will help?" asked the Russian engineer.
-Well, said the observer: "did you ever see toilet paper tear at the tear holes?"
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The problem with all these re-engineering threads is that they may not be addressing the proper problem(s). There are likely a couple of them - not just one. And, it's also likely that some of the problems are not defects in design but rather QC on the motors....
Example - about 600,000 of these motors have been made and installed on P3's. Can anyone find more than 5 people who had the complete separation of the motor? 10?
Assuming that is the case, those cases are probably defective motors (interior wiring, shorts, bad bearings) where the motor heated up to 2 or 3X the design temperature. Nothing is going to stop that.
So let's toss out those defects as being a problem we (the mass of people) are likely to run into.
Next we have the small hairline cracks. There have been guesses like these:
1. Motors too hot
my comment - there are 500,000 P2's out there and sure there are some cracks here and there, but not to a large extent. While the P3 is more powerful, the motors also don't have to work as hard as some of the earlier Visions which were underpowered (meaning the motors had to work very hard).
2. Plastic QC or Design
It's hard to imagine DJI doesn't know how to design a plastic shell. I have many appliances here in my kitchen made of largely plastic which get VERY hot (toasters, coffee machines, etc.).
It is possible that certain runs of plastic shells from the vendors didn't make the grade.
3. Use of Bird
I have noticed that pilots use their P3's much more than the earlier generations - you see many pilots taking them out for constant "distance" runs as opposed to using them for that they are designed for - occasional pics and videos. DJI never put a duty cycle rating on these things (they should), but I think many are using these outside of what they were designed to do.
Point here is that there is always engineering you can do to improve things - likely DJI will slightly tune the formula and construction of the shell. At the same time there is little that can be done about the 1 in 5,000 or that type of motor overheating and short.
Although this stuff is sometimes fun to talk about I am doing absolutely nothing since I think most of the fixes could actually make things worse. I have no cracks, BTW.....
Example - about 600,000 of these motors have been made and installed on P3's. Can anyone find more than 5 people who had the complete separation of the motor? 10?
Assuming that is the case, those cases are probably defective motors (interior wiring, shorts, bad bearings) where the motor heated up to 2 or 3X the design temperature. Nothing is going to stop that.
So let's toss out those defects as being a problem we (the mass of people) are likely to run into.
Next we have the small hairline cracks. There have been guesses like these:
1. Motors too hot
my comment - there are 500,000 P2's out there and sure there are some cracks here and there, but not to a large extent. While the P3 is more powerful, the motors also don't have to work as hard as some of the earlier Visions which were underpowered (meaning the motors had to work very hard).
2. Plastic QC or Design
It's hard to imagine DJI doesn't know how to design a plastic shell. I have many appliances here in my kitchen made of largely plastic which get VERY hot (toasters, coffee machines, etc.).
It is possible that certain runs of plastic shells from the vendors didn't make the grade.
3. Use of Bird
I have noticed that pilots use their P3's much more than the earlier generations - you see many pilots taking them out for constant "distance" runs as opposed to using them for that they are designed for - occasional pics and videos. DJI never put a duty cycle rating on these things (they should), but I think many are using these outside of what they were designed to do.
Point here is that there is always engineering you can do to improve things - likely DJI will slightly tune the formula and construction of the shell. At the same time there is little that can be done about the 1 in 5,000 or that type of motor overheating and short.
Although this stuff is sometimes fun to talk about I am doing absolutely nothing since I think most of the fixes could actually make things worse. I have no cracks, BTW.....
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What you are saying is not true, the screws are not cooler they are by far the hottest item in the photo. Look at the IR pictures I shot, it is a truer indication of the temperature. I am a certified thermographer and can say with confidence the screws in the original IR pictures that look cooler are not cool at all, the image of the screw is near 100% reflected temperature of the sky, the trees above, ceiling of the building surrounding the P3 or as likely as anything the cloths of the person shooting the picture. That is why I always cover metal targets with something that will be heated up but will not reflect false temperatures. Some types of paint, carbon black, electrical tape, latex, are a few examples. Coke and beer cans, smooth metal surfaces (of which the screw in the picture) reflect everything so if you are standing in front of the target you are shooting the temperature of yourself or whatever is behind your IR camera lens.
Since the screw you are referring to has not been prepped in some manner, the image of the screw relates exactly ZERO temperature information.
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found three cracks in the p3 today...going back for new shell
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I think it is best to send it back in and simply go without for a bit. They should be forced to deal with their f-up.
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I'd say you are correct - especially since they are trying (and according to some succeeding) in speeding up the repair times.
For most there is no need to send in instantly though - maybe you have some fall pics on the schedule. Repair times are likely to shorten in the future so no harm in keeping for a few weeks (in most cases).
If mine ever cracks I'd probably DIY. Then again, I've taken numerous macbooks apart to the very last screw....and those things (older ones) are crazy! Luckily there is ifixit with the good instructions.
@Kreso Is this the "new" mount?
View attachment 30117
@Norm Walker - I hope you are right. The Type of plastic and the max temp will have a huge influence. I am no plastic expert but characteristics like load bearing, tear resistance, Rigidity and tensile strength differs highly between plastics. In some cases will heat actually make "protect" some plastics. See Which type of plastic sheet do I need for my application? | US Plastic Corporation
We probably take it to far, but heck, how else would you cover the bases
Klipkop,
how are the motors connected -- soldered or connectors? Also, is there a model number on the motor?
Hmmmm, is anyone concerned buy the heat signature of that PC board?
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Look at all that red and white, wow!
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Look at all that red and white, wow!
So what can be done to fix this? Can we get a bottom half of the P3 shell made of carbon fiber?
I love it when people refer to themselves as "certified"!
as if we need not question it any further. Sorry no offense though and I was not in anyway counter commenting your report and agree with your comments fully. . I think the misunderstanding is I had mean that the screws would likely be cooler than the motor base which is logical right? Yes I certainly agree the screws are hotter than the surrounding plastic frame.
Maybe that material they found at Roswell in 1947 would be a good material for the P3...very lightweight and indistructable.
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No offense taken. I was chosen by by straw draw to go to the FLIR class and become certified. Only 3 people work where I do so I am sure the straws were rigged. It does help interpreting the images that in a previous life I worked as a photographic technologist for the DOD designing and fielding camera sensors and systems including IR. More than anything I love science and IR, especially in the long wavelength, intriguing me to no end. Even though it is an image that everyone can see and assume what they see, the reason things look the way they do are not intuitive. If you look at the images I shot of the screws after the flight you will notice the screws with tape appear radically different in temperature and appearance that the single un-taped screw, they are the same temperature. I did that on purpose to illustrate IR images do not always indicate reality. The first images taken by the OP, some assumed the screws were cooler than the surrounding plastic, that assumption is dead wrong.I love it when people refer to themselves as "certified"!
I really did not mean to be condescending by stating I was a certified thermographer. As a scientist, and having worked with engineers most my life I have learned certifications are typically worth the paper and ink it took to print them. Knoledge is what is valuable here. It was actually my hope by posting the results of my rudimentary research regarding motor heating and thermal transfer to surrounding plastic bits others might be able to shed some light on our problem with the P3.
I have learned something from you today sir! Thanks for the great insight which I can clearly see is more about coming from your experience than the "certification" I agree on your comment " I have learned certifications are typically worth the paper and ink it took to print them" I have been employed for 20 years as a senior executive engineer in charge of a group 8 engineers and I am fully self taught in three different fields of engineering and with no degree for any of them. Its about how you think, cert no cert. Cheers
Very nice image and good thinking. In the case of prop guards though, I wonder if the prop guards could actually be removing heat since they are in the draft of the propeller and may actually be a bit cooler than the surroundings, and act as a heat sink? I realize plastic is not an ideal conductor but still, cold plastic can move heat from warm or hot plastic. Any chance of getting a thermal image after running the same Phantom WITH prop guards?
An Ideal solution might be an aluminum plate as you suggest with short tines protruding just a bit into the prop wash.
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2 ideas for the experts out there: 1) A full replacement of the end of the arm for a better material. Cut the end of the arm and insert a new one. 2) Place a sheet of insulation between the motor and the plastic. Just a thought
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