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Which rings to use with Canon 5diii

Discussion in '3 Axis Gimbal' started by Grant Campbell, Sep 5, 2013.

  1. Grant Campbell

    Grant Campbell New Member

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    Hello everyone

    Question...

    Does anyone has suggestions on which color rings to use in the dampeners for use with a canon 5diii with a 17-40 lens. The total weight of the camera is 3 pounds 7.7 ounches.

    I know the dynamics of the rings depend on temperature, so my area is 60-75 degrees Farenheit (or 16-24 Celsius)...so cool(ish)


    so far I've tried all red. Not too bad. I tried 50%red 50%blue. Only a couple brief flights and didn't have great success, but it was such a small sample size its hard to tell if the rings were the source of the wobble.

    In both cases there is wobble. With the mixture of red and blue the wobble seems a bit more violent. With straight red maybe the wobble is just a bit more gentle and less responsive (active).

    Thanks
     
  2. Brad Meier

    Brad Meier Active Member
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    There is so much that factors into a vibration issue. I will say I use blue rings with my 5d3 16-35 combo but with red rings there isn't a whole lotta difference. First thing, balance props at blades and the hub. I also mount a gopro to a boom near the hub and see if any vibration is showing on the video. Once you getting smooth video there you know your close to a smooth machine and can eliminate that as being the cause for the most part. Next you can concentrate on rings and radian settings if you are running those.
     
  3. Grant Campbell

    Grant Campbell New Member

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    Thanks for that Brad.

    I like your GoPro idea and the whole idea of isolating the heli from the rest of the system.

    I'm going to do some tweaking to the system tomorrow morning and go out for some test flights if the thunderstorms pass:)
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Based on some research I've been doing, I'm measuring accelerations as high as 20 meters/second/second from out-of-balance motors -- true, nothing moves very far, but I was surprised to see that level of acceleration being registered just from spinning up a motor on a CS8 boom using MK Tool (the prop was NOT on the motor).

    The suggestion is, therefore, that motor balancing might be as important as prop balancing.

    Andy.
     
  5. Grant Campbell

    Grant Campbell New Member

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    That's crazy Andy! Strong vibrations! I could definitely see unbalanced motors would effect the motion quite a lot!

    I've looked for solutions to balance motors...and found:

    2 youtube vids that seem interesting. One using a laser and mirror, and one using a seismometer.

    I've tried the seismometer just now, and I get what I'd expect, which is motion detected. I feel my seismometer is a bit overkill (ie. impossible to make completely smooth). I like the laser idea, reflecting a laser beam onto a far wall to see the motion.

    Anyone out there have other good solutions for balancing motors? I'd love to not have to take each motor off the heli if possible.

    Grant
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Grant:
    Using the iPhone app "Vibration" seems to be quite popular. I use the technique of either placing a patch of tape at some arbitrary point on the motor's bell, then making five observations: tape at that point, then then 90, 180 and 270 degrees from that point (you can choose the point using the vendor's name on the outside of the case. The fifth observation is without any tape.

    Once you get a sense of which "quadrant" makes things better, then you can hone in on where the best place is and how much weight is required.

    I've also used the technique of using a cable tie -- the "latch" on the cable tie is enough addition weight that you can use that as the "load" and just turn it to 0, 90, 180, 270, and remove it.

    I happen to be using a Vernier.com accelerometer with Logger Pro software, but the iPhone app or equivalent is pretty good.

    Andy.
     
  7. Nick Adams

    Nick Adams Member

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    Hey Grant,

    I have tried just about every combo of vibration rings and I have found all black rings work the best for me. I am not saying this is correct as I have never balanced my motors (now on the 'to do list', Thanks Andy:)) So maybe I would not need blacks if my motors were properly balanced??? I also have a double star plate just FYI.

    My ten cents worth,

    Nick
     
  8. Nick Adams

    Nick Adams Member

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    Oh and I forgot to mention, I use a 24 mm IS not a 17-40
     
  9. Grant Campbell

    Grant Campbell New Member

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    Thanks Andy...I found the Vibration app....not before installing a different app than what I thought I was getting;) Nothing that wild...just a music app of some sort. [Mental note: Must read before clicking].

    That's something to think about Nick. I spoke with the guys at quadrocopter a short while back. I went for a little tour down there at their 'Labs', (which was Awesome!) and they mentioned something about the double star plate. I didn't get a chance to see it but was interested. So it sounds like you're running 8 mounting points...all with blacks? Seems like I might like this setup. As long as the piloting is smooth I think it could work really well.

    The thing I seem to get with my video is pretty good smoothness...and then every few seconds I get a solid jerk. (this is when flying alone with stabilize on, but no pan-lock) I haven't isolated what that motion is quite yet...to busy elsewhere, but I'm going to watch the video in ultra slow and see if I can figure out if there's a common direction.

    I've been busy balancing motors, which is an interesting task. I tried the tape trick...but these motors fling the tape off so fast I can't even find the first piece I started with...it's like it just vaporized! I'm going to try to move onto the zap-strap method...but these motors accelerate so darn fast I might need a combination of the two.

    Once I'm done I'll re-balance props...its been a few flights now and maybe something's gone out of whack. Maybe test tomorrow.


    Grant
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Reading before clicking is for wimps! :)

    Can you post an example video of the good solid jerk? (And I don't mean a picture of someone you dislike.)
    Which axis is doing the so-called jerking?

    1. If you use white plastic electrician's tape, you may need to burnish it on.
    2. For that piece you can't find, check yourself in the bathroom mirror. Forehead? :)

    You don't need to take them up to warp nine -- just use MK Tool to crank it up to about 127. That produces a no-prop RPM of about 10,000 which is much faster than you'd normally see with a prop (which is around 6,000 - 7,000).

    Balance both the blades and the hubs. :) I found some 1/4 lead tape on Amazon. http://www.amazon.com/gp/product/B004MSKL3M/ref=oh_details_o04_s00_i00?ie=UTF8&psc=1
    Burnishes down nicely on the side of the APC 14 x 4.7 prop hubs. You should only need two or three 1 cm long pieces at most unless the prop is way, way, out of balance. I have one prop for which I cannot balance the hub. I gave up after about 10 piece of lead tape....

    This tape also works on the motor bells. Typically I find I need somewhere between 5 mm to 10 mm to improve the balance, although I am curious to see whether it's possible to really properly balance a motor. I'm continuing to research that question.

    Andy.
     
  11. Grant Campbell

    Grant Campbell New Member

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    Too funny...no sooner did you say check the mirror I was running my fingers through my hair to find that little missing tape:)

    Turns out I didn't keep any of my most recent footage..i guess i figured the last thing I need on my hard drives is crap footage. I've already got about a zillion photos like that clogging my storage. But I'll do another test flight and if its doing the same thing ill put up a vid for sure.

    I like this tape idea. I'm not running mk, so I don't have the same speed control options:(

    So you're saying you weight the motor and blades with this tape rather than filing off some motor weight here and there? And it stays semi permanently?

    Grant
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    So did you find the missing tape?

    No sweat on the video footage. Post it when you have it. :)

    So what kind of motor speed control do you have? Can you set it to mid-range (approximately hovering power setting)? That's probably the best.

    For plastic props, I sand off from the rear side of the heavy blade. For Xoar/wooden I use Scotch tape on the rear surface of the light blade. For the motors I use that lead tape that I burnish on with the cylindrical barrel of a ballpoint pen or equivalent. I've not lost any tape yet (although I should check in my mirror...)

    Andy.
     
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  13. vincexs

    vincexs New Member

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    Anyone out there have other good solutions for balancing motors? I'd love to not have to take each motor off the heli if possible.
    Grant
     
  14. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Grant: Welcome to the forum.

    If it's not too much trouble, would you be kind enough to change your user name to your real first name and last name, please? The reasons for this (and how to do it) are explained here: http://forum.freeflysystems.com/index.php?threads/real-names.497/


    Also, I have deleted the link at the end of your posting. It's inappropriate for this forum.


    Thanks
    Andy
     

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