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Weird shakes in mid air (video)

Discussion in 'General Discussion' started by moswissa, Mar 30, 2015.

  1. moswissa

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    Hello guys!

    I have a concern I wish to address. I noticed last time when I was flying my drone out of no where it would shake/tilt for a spit second or 2 while cruising in mid air. During this flight I was flying very aggressively meaning I was on the sticks pretty hard if that makes any sense. You can clearly see the shaking in the video it happens from :58 to 1:30. There was absolutely no wind. The bird was calibrated. All batteries were 100%. I landed the drone right away. My only theory is that my drone was getting caught in its own rotor draft which caused some turbulence.

    I tried to replicate this and couldnt. Basically when I'm hovering in place I don't get the shakes.

    Any suggestions? And sorry for the crapy YouTube quality

     
  2. KC@UAV-Outlet

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    One thing to remember is, even though there is no wind at ground level, there can be a pretty steady breeze up off the ground. Actual wind measurements you see for weather readings are actually taken at 20 feet in the air to get away from ground clutter, etc.

    That being said, the one thing that comes to mind from your post is the end points on the gimbal motors. You said you were flying pretty aggressively, and that can cause the gimbal to be pushed to it's limits. When you hit the "endpoint" for the motor, it will kick back a bit. You can see that by powering the system up, and tilting it around in your hands, with extreme or aggressive tilts, you'll notice the gimbal kicking back against it. I would re-create the flight with a much smoother attitude, and see what kind of results you get. Chances are that's the issue.
     
  3. n6vmo

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    Looks like a great day in SB...Hope you get your flight issues squared away.
     
  4. rockhoundrob

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    I am not an expert, but it looks like you have 2 problems.

    1) I noticed your video is dipping up and down ( no matter which way the phantom is going/facing). I would suspect this is a gimbal problem.

    2) When you were going down, the video was rotating. I recognize that as the phantom getting caught in it's own vortex. To avoid that, move to one side or another a little while going down. Even full sized helicopters have to watch out for those. When they come in for a landing, then come in at an angle.
     
  5. moswissa

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    yeah that is exactly what's happening, I notice it shake up and down which is what concerns me. I have inspected the gimbal and it looks to be functioning well. it moves up and down like it should. the 4 cushion balls appear normal to me.

    I watched the video several times and I cant seem to understand what you mean by the video is rotating. It could be deliberate as I was descending at an angle. I try not to descend straight down because im aware of this vortex. even when I do descend back and fourth I notice the bird jitter a bit as if it did get caught in its own wind. maybe im not doing that right.
     
  6. rockhoundrob

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    Maybe I should not have said rotating... Maybe it would be better if I said oscillating like a toy top out of balance (the toy that spins) You can see the video move up, then over, then down, then over the other way. It is pretty fast which is why I was suspecting vortex. I notice it at about 1:25... then it stops when it is around 1:45 and that is when the phantom is gliding in rather than going straight down. The vortex isnt a problem, just that its the way he was flying.
     
  7. Narrator

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    Yep.. looks like:
    wind that you won't get at ground level
    VRS
    camera angle.

    On the camera angle thing, notice that the further down you tilt, the less effective the gimbal. That's because it doesn't have a motor that will smooth the point down angle. Tilt it sideways when it's facing up and it will retain level balance. Tilt it sideways while the camera points down and the camera will not remain level. And that will vary according to camera angle.