[Video] Why does my arducopter shake during descent?

[The shaking happens at about 1:58 in this video]

 

[The shaking happens at about 1:58 in this video] 

I have been flying my DIY Y6 daily in Stabilize mode (still waiting for that backordered GPS for other modes) and am very impressed with the stability of this beast.  However, when I descend quickly then try to hover the copter shakes relatively violently... is this an issue with my machine, or an issue with my piloting? (I assume the latter, but I am an eternal optimist lol)

Bonus video: some (mostly) smooth flying around a park (first video with a GoPro mounted to the frame)

 

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  • Developer

    This is caused by the copter going through it's own prop wash (sorry but I don't agree with JD).

    I find that there are decent speeds that this is really bad but others where it is fine. For example, I can drop at about 2m/s and it wobbles all over the place but above 5m/s it is steady as a rock (dropping like one too).

    If you want to descend smoothly make sure you have a good amount of forward speed as you descend. For example, rather than coming straight down, come down at the same decent speed but at 30 degrees like a plane would. This means the copter isn't descending through it's own prop wash and really reduces the wobbles at any decent speed.

    Reducing the Rate PID for roll and pitch will also tend help but you are sacrificing normal flight performance. In any case the copter is always struggling in the vertical decent situation.

  • Fix pitch copter have the issue of oscillating on fast descents. The reason is the construction of the props, to go down in altitude, the copter has only one possebility, reduce the prop speed, become more wobbely. The better balanced the copter and props are, the less oscilation you should get. Only option to descent rock solid is a variable pitch copter, with the ability to correct with negative pitch.

     

    Hope that helped

    J

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