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Statistically, which component will fail first? (excluding props and batteries)

Discussion in 'Pro/Adv Discussion' started by SpaceDan, Sep 13, 2016.

  1. SpaceDan

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    Let's say you have 100,000 phantom pilots, all flying their phantoms non-aggressively, no pilot error.

    Eventually, over the years, all of them will fail (stop working / fall out of the sky). (A component of the system will fail.) Very few will fail within a year, others might fly 100 hours a year for 5+ years, and I'd assume almost all would fail before they hit 10 years of 100 hours/year usage.

    Assuming new props are installed every 100 flights, and batteries are replaced after reaching 100 hours, what would be the most common component to fail first? The 2nd most common?

    How many hours would the average motor last?

    I'm very interested in what people think about this.
     
  2. ElGuapo

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    The shell will most likely show cracks or start cracking. Some pilots are reporting cracks within the first 40 flights. One guy in this forum, does not fly aggressively, yet his phantom has few cracks.
    Should not be happening, but it is. There is a high rate of shell cracks.
     
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  3. AlexSP

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    That's really hard to tell with any accuracy, I'm not aware of any reliable or proven data on this. There are quite a few P2s out there with hundreds of hours and still flying, so I'm not really sure about the "Eventually, over the years, all of them will fail..." assumption.

    I also have different records for prop and battery lifetime, I've only replaced props I broke myself (every time lol) and all my P3 and I1 batteries are still running fine, some are over a yr old and loooots of hours on the air. Of course degrading slowly with use but no failure of any kind.

    Either way, my guess is that in face of pilot error (of all kinds), the real, fail rate of P3 components is negligible. What really worries me are FW updates and that's why I'm still running 2015 FW on all my DJI stuff. And of course the cracked shells (random, not exactly a component fail) and ESC or compass failure, also of unknown causes.

    Sure, they won't last forever but maybe the Phantom family is still in infancy for any reliable track record on component lifetime.
     
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  4. SpaceDan

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    Every phantom will eventually have a component that fails, the shell and motors won't last indefinitely.
    My angle on asking this question is what parts should we look out for to prevent component failure. And I'm wondering how long before we should replace the motors - does anyone have any info for this?
     
  5. John Locke

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    Watch your motors by spinning them freely with no power. The bearing is the weak link, so spinning them before and after each flight is a good sanity check. You can also hold the motors tight in your palm after each flight to compare the motor temps. If one gets hotter, that's a clue. Generally speaking motors are pretty reliable if you don't impact them with something, like the ground.

    ESC's can blow from overheating, but not very often on a Phantom. If you operate in hot environments (100F+) the risk increases for ESC failure. There is no way to predict ESC failure, and it's too expensive to replace all 4 of them as maintenance. Since it's a semiconductor, it's useless to consider that, too unpredictable. But since those parts carry the most current, and run the hottest, they are most vulnerable IMO.
     
    #5 John Locke, Sep 13, 2016
    Last edited: Sep 13, 2016
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  6. ROD PAINTER

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    I always feel motors after each flight!


    Sent from my iPhone using PhantomPilots
     
  7. AlexSP

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    These motors should last many, many yrs of use. Keep them clean and avoid impacts and mucho dirt and they'll last longer than the enthusiasm of most pilots :p

    These are not highest-quality motors but DJI has quite good brushless on their P3s in fact. Freak things can happen of course but there's no need to obsess or stress about it. They do lose a bit of power over time, very slowly actually, no magnet last forever but even older brushless designs give clear signs before failing and can fly fine for yrs and yrs. Not subtle, but clear signs.

    Differences in temperature after flight don't mean much either, as it depends on a lot of different things. Ditto for differences in "spinning while stopped", doesn't mean much and won't tell much about the actual state of the motor - UNLESS you feel play or grabbing in the bearings of course.

    Also, they're up in the air most of the time and even a little bit of dirt can't harm them. Certainly not the bearings, UNLESS you lube a lot or get them dirt all the time. If sand goes inside, just use compressed air (can or whatever) and it's good again. Lubing is highly controversial, some swear by it others (like me) prefer not to mess with bearings and insides unless something is really weird or not working. Do as you believe it's best, I tell people.

    I have 5-yr old (and older) motors from other RC AC models still running on original bearings, and some are lower-quality and older design than these P3's. I've dealt with different ABEC bearings and all and didn't see much difference in lifespan, because they really last that long. RC cars of course need a different approach.

    My motto with the P3 is, "just fly the **** thing", like any RC AC it's important to keep an eye for weird behavior during flight but that's pretty much it. The P3 is NOT an "assembled" (kit) drone, non-hobbyists are better taking it to DJI or a good shop if something seem out of order with motors or ESC - which, in my opinion, is not as common as some people believe.
     
    Numone and ROD PAINTER like this.
  8. J Dot

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    Just my 2 cents

    First let me say, this question has NO DEFINATE answer! Endless possibilities!

    Personally!
    I'd say on p2, ESC's are the weakest link! As they seem to take the most load!
    ( new to p3 so have no advice there, sorry )
    As for motors,
    I found the motors weakest link are the bearings, nothing else to go wrong, unless you crash, or overheat them ,ultimately melting the windings. Crashes can happen, without user error, but maintenance is users responsibility. A drop of oil, on those bearings, now and again, can go a LONG WAY! ( I ONLY use boca Lightning bearings, on my P2's. ).
    Did some tests: ( here is one ) also did heat tests.
    ( stock vs boca Lightning )


    So as you can see, imagine your motor turning that 9 second stock bearing for say 20 hours, compared to your motor turning the 30 second bearing for the same 20 hours, now add the ( 25-30 degree temp difference between the bearings, stock HOTTER obviously due to increased friction from ( in my opinion CRAPPY ) bearings. )so this being said, my bearings/motors should last at least 3 times longer! Or more?
    ( as heat and friction are reduced )
    which should also in turn put a slightly less load on esc.
    ( 2212, and 2312 motors only, have not done any tests on newer motors/bearings! )

    With no certainty can I say what will go bad, but with COMPLETE certainty, I'T WONT BE MY MOTORS!:)
    Lol.

    But I'd say ESC! If we are guessing!

    J Dot
    :cool:
     
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  9. jwilliam

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    I have a P3P that has 30 hrs 20 min. 24 53,000 ft , 188 flights . I have remove able prop gaurds & after careful inspections (no cracks ) I think that the guard mounts on the copter helped to disperse the stress on the shell from the motor screws ???
     
  10. Mocho

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    +1

    Cool test!
    Are those Boca bearings ceramic? Are they a standard radial ball bearimg, or a combination thrust bearing as well? Wondering how the verticle thrust is taken up? And if that is the area of the bearing your putting a drop of oil on, once in a while :)
    For your test did you consider using a drill with a buffing wheel on it to spin them up to a constant speed ?
     
  11. J Dot

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    Bearings are ceramic hybrid ( steel chase/ceramic bearings. )
    No tests like that, did the spin test you saw, several run tests for noise ( db ) and heat, pinned phantom down, ran motors full ( props on ) 3minutes, 5 minutes, and 10 minutes, testing heat at each motor, ( stock bearings )
    Then replaced all bearings with lightning bearings, ran same tests again, Db was not much difference, a few, but I would almost need to run each motor seperately, but over all, found a 5-8db difference, so threw that out! Too much prop noise, and a weird harmonic of all 4 motors running in unison! But temp. Was a 25-30 degree difference, that was huge for me, I should of done more scientific testing, but just the spin test sold me! I helped boca create a 2312 motor bearing set, ( they were unaware the new motors existed ) ( also working on a separation tool. they gave me a lifetime 10% discount, and a free set of 2312 bearings ( 1 step below lightning ) as 2312's use 2 different bearings. And the 2212's use 2 the same! They only had smaller bearing ( 2312 ) in ceramic, larger was steel! They should have a complete set now, been months since I supplied specs to them!
    But have not checked on s while, as all my birds have boca bearings! Except my p3p, it is stock ( as of now! ):rolleyes:

    For fun and giggles, do you remember the old 1980's RC-10 buggy?
    [​IMG]
    Here was my tool, but don't laugh, it works!


    J Dot
    :cool:
     
    #11 J Dot, Sep 13, 2016
    Last edited: Sep 13, 2016
  12. mikesmiley

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    The shells.
     
  13. Mocho

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    I would like to see one of our P3 motor bearings now that you bring it up!
    And as you mentioned before, and I agree with your sentiment. The bearing is the most likely piece of rotating equipment to fail. So it sounds like a good mod once the warranty runs out.

    I certainly do remember those buggies!! :) They were a hoot but as with most things the newer models took over. In the end I was running Mugen 1/8 Buggies and they are a LOT of fun!

    J Dot what a beautiful looking RC10!! Did you personally hand make it out of wood!?

    But I digress...

    Your tool is ingenious !! :)
    One usually only requires a "special tool" if you can't figure out another way to do it !
     
    #13 Mocho, Sep 13, 2016
    Last edited: Sep 14, 2016
    J Dot likes this.