Prop nut tightening

I have a 2013 Y6 with the old style motor collets with rounded nuts that are tightened with a 2mm hex wrench. I had a crash earlier this year when a prop flew off mid flight despite me having checked the nut tightness prior to flight. Since then I have been paranoid about prop nut tightness.

I changed the nuts to regular M6 hex nuts and use a socket to tighten them. However I still find it difficult to tighten the nuts. While tightening, the sharp edges of the prop are digging into my hand while I am also trying to anchor the motor from spinning. I am sure everyone has had this problem sometime.

Does anyone have any tips for tightening props? Maybe I could find a tool to anchor the motor without having to clamp it. Possibly one of those rubber strap grip tools will do the trick. Haha maybe I have just answered my own question. Time to visit the hardware store.

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  • Couple suggestions for you.  Swap out the standard nuts for these kind, they are self-locking nylon nuts.  Just make sure you get the right pitch as well.  The URL I embedded is an example and may not be what you want to spend money on but gives you a good idea.


    Lastly, I would recommend buying this!  I use the smaller of the two wrenches and wrap it around motor housing when I ratchet down the nuts on motors/props.  Saves me getting cut by the props.

  • I use a highly specialized tool to hold the propeller.  It is called a "rag"...  :-)

    Probably not what you wanted to hear, but I have to say it works just fine.  And I have carbon fiber props which are even sharper than the APC, and it still works!

  • I use Nyloc nuts and always use a self adhesive neoprene washer on the motor spindles that helps the props to seat and not spin. Never ever had a prop come loose even at 120amps and at speeds of up to 70mph..

    Having said that I've never had a crash so I don't know what would happen then.

  • It is unfortunate that for the Y6B orientation, all 6 props rotate such that they will tend to loosen the prop nuts. A better choice would have been for top props to run CCW, bottom props CW.

    • Hi

          I was thinking that very thing about y6 version B all nuts rotate in  undo direction??

      I am going to try reversing all motor directions and change top to bottom motor connections

      yaw    would not be changed?    as far as i can see this is ok

      any one see a problem?


    • That would cause more broken props and Birkenhead motors because they wouldn't be able to loosen on impact. This isn't a simple error, it is done for a reason. Just make sure they are tight enough to stay on in flight.
  • I'm surprised I didn't think of reverse threads. It seems obvious now.

    To be clear, my crash happened when a prop unscrewed mid flight, and yes it was a clockwise prop. I had checked tightness pre flight (rounded nut, 2mm hex wrench). It was obviously not tight enough, hence starting this thread. For me the problem was with control of the tightening. This might be a good reason to get myself a torque wrench. I broke a collet spindle once when it bent slightly after a crash, I straightened it and then tightened the prop and bang! broken :(

    I settled upon my solution - see attached photo. This gives more control.

    Loctite is not an option for me. I often transport. I also test requiring removal of props. Also compassmot turning props upside down. I think removing props more often is actually good practice because it forces you to check tightness every time you put them on.

    I don't think nyloc is a good solution either. The Phantom design sounds clever to me.


    • I transport mine regularly al folded up. Removing the props would save me about an inch in one dimension. The arms fold to the width if the rear prop if you mkve the rear esc's close together to even get that far. You can do compassmot without replacing props, just removing them, saving half the trouble of the process.

      Check props before every flight. At least check them by hand if you tapped one during a series of flights.

      Use Y6B so they can all be the same and easier to buy props for.

      Sure, you can use reverse threads, but it solves a problem I don't think exists. You should still do all of the above, and if you do, props won't fall off unless you whack it so hard you want them to.
  • I use 242 Loctite; never a problem.  Applied well it will remain inside the nut/shaft making it unnecessary to reapply the Loctite every time.

    It is possible to over tighten nuts as it can weaken the hub. Think about how much torque is applied if a self locking prop is spinning at high rpm and it stops suddenly when hitting the ground.

    Probably the best method is to use an inch lb torque wrench if you don't have the right feel.

    An hour to install props? It should be a 10 min job max.

  • The prop nuts are almost a symbolic manifestation of the difference between a 3DR kit and the DJI Phantom.

    The case for my Phantom can be aircraft carry-on size because it is not a priority to stow the craft with the propellers on. Mounting the propellers is such an easy task, it almost makes the drone operator look like a virtuoso. Add to that the clever clockwise/counter clockwise design which avoids mismatching the props to the engines and also counteracts the props loosening in flight.

    For my Y6, I ordered a big-enough case that I wouldn't have to take the props off when transporting it. (It folds down quite tight though, so the case is not that large.) Putting the props on took almost an hour. Making sure the right props got mounted on the right engines was a bit of a stress factor. Add to that the physical stress of tightening the nuts without injury to hands or craft.

    There are some good suggestions in this thread that I am going to try next time I mess with the Y6's props but I also think there is room for improving the design.

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