Vibrations

Discussion in 'Cinestar 8' started by David Tivadze, Feb 21, 2015.

  1. David Tivadze

    David Tivadze Member

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    Hi,

    Just finished my assembly of CS 8 HL.
    Today switch it on and ....... what the hell it could be?
    When I test motors with MKtools everything goes smoothly and fine.
    But , when I switch on motors normally by radio..... huge huge huge VIBRATIONS

    https://www.dropbox.com/s/b8bvfdcv1ifzhwe/IMG_9189.MOV?dl=0

    Have No idea what it could be.
    May be somebody has?
    Thank You
    David
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    David:
    PLEASE DO NOT RUN THE MOTORS WITH THE PROPS ON INDOORS!!! It is sooo dangerous.

    I'll post again in a minute, but I wanted to get this post up on the forum ASAP.

    Andy.
     
  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Ok.....I've calmed down a bit now! :)

    REMOVE THE PROPS!

    Then, have you used MK Tool to check each motor individually? You mentioned that you tested "the motors" but it's not clear whether that was individually or all together?

    Check that when you select motor N (where N is from 1 to 8) that the correct motor spins up and rotates in the correct direction.

    If you then start all eight motors (with the motor test), do you still get the oscillations?

    What Mixer setting do you have in MK Tool?

    It's very hard to see from the video whether all the props are mounted correctly -- the "wagon wheel" effect that happens with video makes it difficult for me to see which way the props are actually rotating. Have you double checked that?

    Andy.
     
  4. David Tivadze

    David Tivadze Member

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    Andy: THANK YOU for Your Warning! I will take into account Your advise.
    Now. I was sure ( I do not know why) that Number 1 motor (RED Boom) should rotate CCW. So, all other motors, in my set up was this way: ALL odd motors CCW, ALL even motor CW.
    The Propeller itself on the N1 motor was as on the photo.
    Now. When I started ALL motors from the MKTOOLS test, everything was perfect, NO oscillations at all.
    BUT, when I started motors (ALL) normally, by stick on my radio, in 2 seconds I got this king of vibrations You see in video.

    It is still strange for me why.

    Now, I reverse all the motors in MKTOOLS and everything is smooth and fine.
    Thank You Andy one more time !
    David
     

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  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I remember it as Odd starts with an O, so OCP. Odd (numbered motors) Clockwise Props.
    So I think you have a completely reversed setup when you first started.

    Andy.
     
  6. David Tivadze

    David Tivadze Member

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    Yes, Andy, everything was just vise versa
    Thanks again, specially for safety issues. In case I need to start motors with props indoor I will wear the protection glass and may be some carton piece between legs :)). Doubt, if any other body places need to be protected as well. :)))
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    David:
    If the motors start up and spin at anything above idle, the copter may take off, fly sideways into your face, cut your hands, arm, neck, eyes, or fly up to the ceiling.
    I would be remiss if I did not repeat myself: NEVER start the motors indoors with the propellers on.

    If you don't already have them, I would suggest you consider getting one of each of these:

    http://www.amazon.com/gp/product/B0076HKPQO/ref=oh_details_o05_s00_i00
    http://www.amazon.com/gp/product/B004Y74AU6/ref=oh_details_o06_s01_i00
    http://www.amazon.com/gp/product/B000E7XGUU/ref=oh_details_o04_s00_i00
    http://www.amazon.com/gp/product/B002S0O7W2/ref=oh_details_o04_s00_i01

    and check these threads
    http://forum.freeflysystems.com/ind...lks-are-using-for-builds-and-maintenance.738/
    http://forum.freeflysystems.com/index.php?threads/how-tight-are-your-prop-nuts.1368/#post-17371

    You can remove all eight props in less than about 90 seconds. A trip to the emergency room will take a lot longer...
    About the same time to re-install them.

    Andy
     
  8. Gary Haynes

    Gary Haynes Administrator
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    David, seriously take the props off indoors. I'd be happy to direct you to the posts from a couple of years ago on another forum where folks posted their terrible injuries, some permanent.

    Taking the props on and off can be a pain, UNLESS, you get something like the Hitachi DB 3DL2 Cordless Driver Drill and the correct sized nut driver. Also get metric hex bits so you can quickly do the various other bolts and do dads. Andy's list of tools is spot on.
     
  9. Jason Smoker

    Jason Smoker Active Member

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    David what motor mounts are those?
     
  10. David Tivadze

    David Tivadze Member

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    Andy, Gary - thank You for Your care. I really will never start the motors with props attached indoors.
    Because , as You can see , the off-on really will take no time, just 2 hex screws for each prop.
    Jason - here You can see some photos, in case, of my newly built copter. The mounts are tarot, I like this mount, especially they can be leveled very easy, without some really "crazy" tips and tricks, that people perform to level the motor axis vertically. Here this operation is easy as 1,2,3
    Thank You one more time
    David
     

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