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Cautionary Prop Attachment Advisory to i1 Owners!!

Discussion in 'Inspire 1 Discussion' started by Transpire, Oct 25, 2015.

  1. Transpire

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    Hi Guys,
    I have flown about 75 times as of this writing. At the startup of the proposed last flight, myself and my spotter heard a sound that that we never heard before. The best way to describe it would be a momentary "ping-ping" and then no other sound other than the typical motor sound. Almost as if you were to lightly tap a wine glass with a fork twice gently. It was enough to cause me to ground the i1 for the day.

    Having not flown since, I wanted to take a look at things to see what the issue was. I spun each of the motors by hand forcefully to get several rotations out of them (no props attached). Three sounded/acted normally. The fourth, exhibited a "ping" when I spun it. I tried again and again and no further pings were heard.

    My thought was that I was going to remove the top two screws on top of the motor and take a look (I have the quick release style prop attachments). I put my allen driver on the screws and they were BOTH markedly loose!

    I then went to the other three motors and they were loose too, although not as much. I extracted the screws and found something VERY INTERESTING. There seemed to be an absence of threadlock. Having dismantled parts of the body previously for various reasons, I found blue threadlock on the body screws, but none on the motor screws. That seems extraordinarily odd to me. I would think that threadlock should be more important on the motor screws than anywhere else! Well, upon further inspection, after extracting the screws, I could see blue threadlock in the screw hole, BUT NONE ON THE SCREWS! Apparently, the blue threadlock installed by the factory, did not adhere to the screws. This is quite alarming considering the importance of these specific screws.

    So, I have added blue threadlike to these 8 screws and reinstalled them.

    I wish to advise all i1 owners to check these screws before your next flight to make sure they are tight and additionally I recommend checking for threadlock and adding it if it is absent.

    Lastly, I would like to hear whether any other members' motor screws were discovered to be loose as well.

    Safe flights everyone,
    Ken
     
  2. The Editor

    The Editor Moderator
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    Thanks for your post.
    I do not use any form of QR props (I threw them in the trash since I consider them am accident waiting to happen) however, checking screws/bolts etc on the airframe and motor fastenings should form part of a normal maintenance regime in any case.
    There is no way on earth I would go 75 flights without a full airframe inspection which would have picked up this problem much sooner.
    I'm glad you found it before disaster!
     
  3. Transpire

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    Thanks Ed. I hear you.
    I have looked through the airframe very frequently. I have check play in the motors and props engagement each flight, reviewed all linkages, checked all accessible wiring connections, and have been logging battery usage. I have to admit, having experienced the very effective threadlock on the body screws, I would have never expected these screws to be loose. My bad. Live and learn, but glad it didn't result in disaster.

    The more important thing, however, is to get the word out to other owners to check these screws and furthermore, to check to see if the threadlock has adhered to the screws.
     
  4. The Editor

    The Editor Moderator
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    I agree - Everybody should check their prop fastenings for security on a VERY regular basis.
    This may also be a manufacturing batch problem (one individual in the factory) who got lazy with the thread lock.
     
  5. Cyclops

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    Hi Mr. Editor,

    Like you I'm staying away from QR propellors - just wondering if you know a UK supplier who is still selling the original sets?

    I've had a couple of trawls with our any luck - Thanks
     
  6. lake_flyer

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    Good that you raise the attention to this. I'm sure many people just expect it to be safe and don't give it a good inspection or even do a proper preflight check. I was very aware of possible risks and never trusted them from day one.

    I would (and I do) suggest everyone to get themselves a couple of pairs of normal self threading props (only about 8 bucks a pair) and just have a look at those. If you notice the metal threaded hub going through and through, realising that each single thread alone is more secure than that entire QL system, you will never want QL's again, before you even tried them out. Just by looking at them.

    The added snap locks give a lot of extra confidence.
    And they look cool :) in signal orange.
     
  7. The Editor

    The Editor Moderator
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    The original self tightening props are available direct from DJI (in three varieties of colour) although postage is rediculous so you may find they can be ordered from a dealer and they will put it on their next order through to DJI.
    Other than that, I think most dealers were cleared out of the self Tighteners when the QR were introduced.
    I know I cleared out a couple of dealers of all their stock straight away so I had sufficient for the life of my Inspire......sorry. :(
     
  8. lake_flyer

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    20151025_091845.jpg
     
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  9. lake_flyer

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    When I ordered them at DJI China, recently, they were delivered to NL after only 4 days (including the weekend). The envelope was stamped off in China. The 15 Euro shipping cost seems a lot but it saved me 10 Euro on petrol and at least 2 hours to get them at a local shop (if they have them at all). And if you order 6 pairs the total shipping cost remains the same.
     
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  10. Cyclops

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    Thanks for the reply - I'll order direct from DJI
     
  11. RGD

    RGD

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    Is there anywhere that the screw on props can be purchased. I only see the quick release advertised
     
  12. lake_flyer

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  13. The Editor

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  14. lake_flyer

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