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Repeatedly Installing/Removing Props, Do they Get Loose?

Discussion in 'General Discussion' started by QuadBart, Feb 9, 2016.

  1. QuadBart

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    Was wondering if constant installation and removal of the props causes them to eventually not tighten down enough? Kinda like either a wood screw in wood, or a lock-nut that after repeated installation and removal no longer works properly?

    I ask as I have the hardshell backpack which requires prop removal and it got me thinking...
     
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  2. Buckaye

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    @QuadBart I have removed and re-installed my props a lot... and I have not noticed any change. I think you should be fine if you don't over tighten. I'll admit it's anecdotal information only.
     
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  3. Monte55

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    You don't say which props. I doubt it would ever be a problem with metal hubs but the composite hubs may get looser over time
     
  4. eaglegoaltender

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    QuadBart Most probably will loose some grip and proper fit if they are over tightened each time they are installed. Proper care and "hand tighten" during install should be fine as to retaining the quality of thread, securing and life of props. It's over tightening (bottomed out) that will "stretch" a nylon or plastic thread resulting in some extra clearances between them (thinner). Good news is they are self tightening when operating and people tend to forget that and over tighten when installing.

    Nylon nuts on steel bolts do lock up nicely (nylon thread molds itself around the metal) when they are not forced on or over tightened. Rule for me with these is - when I first fire up the Phantom I give it a couple of 'revs" to help lock the props in place - then hover for 30 seconds or so prior to any flight - if I am going to loose a prop due to poor fitting, it will be on start-up most of the time.

    The supplied plastic "wrench" is for removal and not for installation as some tend to use it for - since a wrench is sometimes needed to loosen them off, it shows the self locking is working fine. If you find it is becoming easier to remove (unlock) the props for removal by hand only, I would say it is time then to look into replacing them (by easy I mean next to no effort when removing them). I have the same hard shell backpack and have to remove them also for travel or storage - worth the investment, I would think to get a case where the props can remain on the Phantom.
     
  5. Skywalker

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    Actually the reverse. They tend to grip tighter as they are used and the threads conform. That's why you sometimes need a wrench to take them OFF. (Never on!)
     
  6. QuadBart

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    Thanks for the help guys. I use the stock props...
     
  7. TheRealNick

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    I have seen and analyzed at least three crashes where the props came off, sometimes several minutes into the flight. On the DJI forum it is the number 2 reason listed for crashes:

    DJI Forum|TOP 10 common pilot errors

    So they are not completely self tightening. I agree not to use the wrench but definitely use both hands. I think I spin them down and then do about a 1/8 turn. I can still take them off with my hands, I may be slightly over tightening them. I also pay attention to the amount of force it takes to install them and if it felt different I would replace them.
     
  8. GoodnNuff

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    #8 GoodnNuff, Feb 9, 2016
    Last edited: Feb 9, 2016
  9. wolvesfc

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    Not exactly unrelated, but how long do props last? Is there any sort of time limit/ flight hour limit with regards to changing them?


    Sent from my iPhone using PhantomPilots mobile app
     
  10. Mark The Droner

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    Using a wrench to tighten props doesn't make sense unless it's difficult to achieve adequate torque without a wrench. And it is not.
     
  11. TheRealNick

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    I have not seen any real sudden decrease in prop speed in the data where the props fly off. Below is a chart of motor speed thanks to @BudWalker's datconverter of a prop off event.

    propoff.png

    You can see some fluctuations in speed, but there is nothing atypical just before the prop comes off and the speed jumps. I think people are confused about the braking feature that is in the DJI GO setting. What it does is automatically apply reverse stick to slow the Phantom down. For example, if you fly the Phantom forward and then center the stick the Phantom will automatically angle backwards to stop quicker. You can adjust how aggressive this it, but this is no different that what everyone has to do on a quad that doesn't have this feature. I do it manually all the time on my Syma X5C and Estes Proto....to slow them down when I fly forward I have to actually push the stick backwards unlike the Phantom....

    Also, I do not recommend using the prop wrench. Does anyone know what kind of plastic the props are made from? If we knew some of the material properties we may be able to calculate the max angle you can rotate the prop to stay in the elastic zone. For those that do not know, as you stretch a material most have what they call the elastic zone and the inelastic zone. Picture a metal rod, you can stretch it a little bit and it will go back to its original length, that is the elastic zone. If you stretch it really far you go into its inelastic zone and it will be permanently deformed. When tightening the Phantom props you do not want to go into the inelastic zone....
     
  12. TheRealNick

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    I did some searching and will inspect my props later, but the best way may be to just try different rotation angles and see what causes it to mess up the props and how many cycles we can get. There was another poster that said they trash their props after 20 flights, I send him a PM to see if he was interesting in shipping them to me and I would see how many more cycles they get, see how far I can turn them before damaging them, basically do some destruction durability testing. Alternative, if someone has some broken props and motors we could talk about how they could test themselves and post the results back....
     
  13. Meta4

    Meta4 Moderator
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    That whole thread was from the time before anyone had a P3.
    It's all about the P2 with metal hubs.
    DJI came up with the nylon threads in the propeller hub to deal with this situation for the P3 and overtightening nylon threads with a wrench is definitely not the thing to do.
     
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  14. Meta4

    Meta4 Moderator
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    The order in that DJI forum post is random and is unrelated to how commonly those problems cause crashes.
     
  15. TheRealNick

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    I saw someone ask if order was in frequency and DJI Dave said he didn't personally think so (DJI Tim wrote the original post) but I couldn't find a definitive answer, then a bunch of people railed them for the #1 being a CSC and they didn't seem to say it wasn't. Either way, if it is number 1 or number 10 to me it is enough such that people should tighten there props carefully....reading though the list and looking at the crashes I have seen posted here it is pretty frequent along with battery issues....
     
  16. Meta4

    Meta4 Moderator
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    Unfortunately the DJI forum people are quite unreliable when it comes to accurate information or knowledge of the Phantom. (DJI-Ken excepted)