Shop OBEX P1 Docs P2 Docs Learn Events
Elev-8 reducing vibration — Parallax Forums

Elev-8 reducing vibration

ctilley79ctilley79 Posts: 10
edited 2014-01-27 21:12 in General Discussion
I recently assembled my Elev-8. When I mounted my go pro i realized how much my copter vibrates. Possible cause could be propeller balance is off. I did notice when installing the props it was very difficult to mount them in a way where they didn't slightly wobble. The the bushing that goes in the propeller is only inserted in the bottom and leaves a little play in the hole in the top. Does anyone here have any solutions to reduce vibrations in this craft?

Comments

  • Nick ErnstNick Ernst Posts: 138
    edited 2013-01-17 16:50
    Hello ctilley79,
    The Vibration that you saw in your video is most likely what is known as the "Jello" affect. There needs to be a small buffer between the camera and the point of contact on the copter where you are mounting your camera to. I like to use some double sided tape, as it serves to reduce the Jello affect, and to also give me a little more adhesion between my copter and my camera!

    As for the gap and wobble you mentioned, if you could take a picture of the motors with the issue and post it here so that I can take a look at it, that would be great, as that will give me something to have a look at.

    We'll get you back up in the air and flying in no time!
  • ctilley79ctilley79 Posts: 10
    edited 2013-01-17 19:25
    You can hear it too. I did notice the wavy distortion in the video as well but that is not what's going on here. You can hear it on the video as well and feel it during testing when I bench test the copter.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2013-01-18 06:09
    This may be a case of doing a lot of little things right. Generally parts that are out of balance contribute to vibration. I presume the motors run smoothly without propellers attached.

    http://www.youtube.com/watch?v=N02NHYrpA0g
  • ctilley79ctilley79 Posts: 10
    edited 2013-01-19 06:44
    The motors run well without the propellers. When you spin the props by hand, you can see the propeller spinner/collet wobble up to a millimeter from from the verticle axis, therefore about 2 millimeters when prop is spun 180 degrees from the start point. I may see if I can find some more precise collets online, as the stock ones just don't cut it. That would make a big improvement. In my opinion the waviness in the video is made worse by the fact that the camera is vibrating. If I can smooth out the vibration, I believe it will help video quality. I'll post back if I find some results. The camera is mounted on top of the red elev-8 top plate. I will provide video once I get back in town.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-01-19 10:52
    ctilley79 wrote: »
    When you spin the props by hand, you can see the propeller spinner/collet wobble up to a millimeter from from the verticle axis, therefore about 2 millimeters when prop is spun 180 degrees from the start point.

    Could you take a picture of this? This seems very strange. Did you include he little round inserts inside the propeller?

    Post #19 of the ELEV-8 camera thread has a video I made using an ELEV-8. I thought it turned out reasonably well. The same post shows my mounting method (cable ties).
  • ctilley79ctilley79 Posts: 10
    edited 2013-01-19 12:59
    Duane Degn wrote: »
    Could you take a picture of this? This seems very strange. Did you include he little round inserts inside the propeller?

    Post #19 of the ELEV-8 camera thread has a video I made using an ELEV-8. I thought it turned out reasonably well. The same post shows my mounting method (cable ties).

    Yes the spacers are in. The spinner and collet is the issue. The collet is mounted directly on the motor shaft and tightened with the spinner nut, both of which should be perfectly vertically aligned. The wobble is in the collet not the prop itself. Here's a video which may show what I'm talking about. I would like to show a video of me manually turning the prop but this is the best I have since I'm out of town.

    P.S. I can't wait to upload the full video. Shot on a cold morning after 4 in of fresh wet snow. Kinda cool.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-01-19 21:24
    ctilley79 wrote: »
    The spinner and collet is the issue.

    The spinner in your video looks like it wobbles. I wonder if you received a bad batch?

    Once you take some photos/video you might want to contact Parallax customer service to see about a replacement.

    We've got a lot of snow here in Idaho. Where are you?
  • garyggaryg Posts: 420
    edited 2013-01-19 21:45
    While I'm not familar with the Elev-8 in particular, I am somewhat familiar with using collets.
    Relatively good collets usually mount in a very true manner.
    If you completely bottom out the collet, It's very possible that the collet cannot grab the shaft correctly.
    I've had out of true running with Router bits and Dremel tool bits.
    If I have a collet assembly running out of true, I always loosen and remove the collet.
    Clean again with compressed air to be sure there is not a bit of swarf in there to keep the collet from grabbing correctly.
    I replace the collet again, making sure to not completely bottom it out.
    Then, when I start to tighten the collet, I twist it several times while the collet nut is not completely tight.
    This solves my router bit out of true and my Dremel collet out of true issues.
    The other thing that I have observed is that occasionally, I do get a bad collet.

    That's just my 2 cents worth.
    I hope it helps you in some manner.
    gg
  • ctilley79ctilley79 Posts: 10
    edited 2013-01-20 05:36
    Duane Degn wrote: »
    The spinner in your video looks like it wobbles. I wonder if you received a bad batch?

    Once you take some photos/video you might want to contact Parallax customer service to see about a replacement.

    We've got a lot of snow here in Idaho. Where are you?

    I believe it was a bad batch. They looked really cheep. some had threads longer than the other, some the collet looked odd. I am going to research some new ones. Regarding the snow, I'm in south central va. We only get snow a couple times a year, so it's always fun when it happens :)
  • jonbetzfilmsjonbetzfilms Posts: 10
    edited 2013-12-16 17:09
    ctilley79 wrote: »
    I believe it was a bad batch. They looked really cheep. some had threads longer than the other, some the collet looked odd. I am going to research some new ones. Regarding the snow, I'm in south central va. We only get snow a couple times a year, so it's always fun when it happens :)

    Have you found a solution? I just finished building my Elev-8 today and when I took it out for the first flight, I had the same issue. I made sure all screws are tight and eventually identified the collets as the problem. If I remove them, arm the copter and give it a bit of throttle, all of the motor shafts seem to be very straight (no wobble). If I touch them while spinning, they feel quite smooth. If I put on the collets and repeat, I feel a lot of vibration in the spinning collet (without prop. I just used the black plastic prop spacer to allow me to tighten the spinner on the collet). I can see the wobble and feel it. I tried lifting the collets slightly to ensure that they are not bottomed out on the shaft, but that did not help. Three of my collets are wobbly, and one is fine. Can you buy replacements without buying a new set of motors? Thanks for the help.
  • ctilley79ctilley79 Posts: 10
    edited 2013-12-16 17:39
    jonbetzfilms wrote: »
    Have you found a solution? I just finished building my Elev-8 today and when I took it out for the first flight, I had the same issue. I made sure all screws are tight and eventually identified the collets as the problem. If I remove them, arm the copter and give it a bit of throttle, all of the motor shafts seem to be very straight (no wobble). If I touch them while spinning, they feel quite smooth. If I put on the collets and repeat, I feel a lot of vibration in the spinning collet (without prop. I just used the black plastic prop spacer to allow me to tighten the spinner on the collet). I can see the wobble and feel it. I tried lifting the collets slightly to ensure that they are not bottomed out on the shaft, but that did not help. Three of my collets are wobbly, and one is fine. Can you buy replacements without buying a new set of motors? Thanks for the help.

    What I did was purchased collets from another manufacturer. You can buy them from any large online hobby shop. Even amazon has them. They are about 3 dollars each from what I remember.. Buy a lot, you will damage them over time.
  • jonbetzfilmsjonbetzfilms Posts: 10
    edited 2013-12-16 18:19
    ctilley79 wrote: »
    What I did was purchased collets from another manufacturer. You can buy them from any large online hobby shop. Even amazon has them. They are about 3 dollars each from what I remember.. Buy a lot, you will damage them over time.

    Thanks. Did that solve your wobble issues?
  • ctilley79ctilley79 Posts: 10
    edited 2013-12-16 18:57
    jonbetzfilms wrote: »
    Thanks. Did that solve your wobble issues?

    Yes.
  • jonbetzfilmsjonbetzfilms Posts: 10
    edited 2013-12-16 19:13
    Excellent. Just ordered a new set plus a few extras. Hopefully this solves my problem as well. Thanks for the help.
  • jonbetzfilmsjonbetzfilms Posts: 10
    edited 2013-12-19 14:20
    ctilley79 wrote: »
    Yes.

    I received my collets and they do not work. They are E-Flite 3mm collets, and the Parallax website lists the motors as having a 3mm shaft. The collets are slightly too small for the shafts and do not go on. Are these actually 3.175mm shafts? Which did you buy? Thanks again.
  • trangertranger Posts: 179
    edited 2014-01-01 11:10
    The motor shafts are nominally 3.175mm. Mine check just under 0.125" with a micrometer, maybe 0.1248" ~ 3.170mm. They end up being a light press fit in the motor bell and a slip fit thru the bearings. I haven't tried any other collets besides the ones the come with the motor. Unfortunately, these seem to survive impact while the shafts bend.

    After a quick look, the only online parts I could find come on a slow boat from the far east. However, you may be able to find something out there.
  • jonbetzfilmsjonbetzfilms Posts: 10
    edited 2014-01-12 21:29
    tranger wrote: »
    The motor shafts are nominally 3.175mm. Mine check just under 0.125" with a micrometer, maybe 0.1248" ~ 3.170mm.

    Thanks for this. Very helpful. I just ordered some new 3.175mm collets that will hopefully work. Parralax should correct the specs on the motor listing from 3mm shaft diameter to 3.175mm shaft diameter. Unfortunately since most of the cost of the 3mm collets I purchased was for shipping, it is not worth it to return them. No big deal, but it would be nice if others could avoid this issue.
  • jonbetzfilmsjonbetzfilms Posts: 10
    edited 2014-01-27 19:31
    My new 3.175mm collets work perfectly, and this did solve my wobble issue. If anyone from Parallax is reading, the shaft diameter for the Elev-8 motors should be listed accurately as 3.175mm to help others avoid making the same mistake I did.
  • Ken GraceyKen Gracey Posts: 7,392
    edited 2014-01-27 21:12
    jonbetzfilms wrote: »
    If anyone from Parallax is reading, the shaft diameter for the Elev-8 motors should be listed accurately as 3.175mm to help others avoid making the same mistake I did.

    Thanks jonbetzfilms! We'll get that corrected on the product page on Tuesday.

    Ken Gracey
Sign In or Register to comment.