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Weird twitch while descending....

Discussion in 'Phantom 2 Discussion' started by Biggunzz, Jan 10, 2015.

  1. Biggunzz

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    I have a phantom v2.0 stock...When I am descending and moving forward, I try to yaw left or right the copter stets to twitch out of forward pitch. only after I stop yawing or trying to pitch, does the twitching stop. So only in full down(not locked), full pitch and full yaw does this twitch occur. Any ideas? I have calibrated the compass and updated to all current firmware.
     
  2. Mako79

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    Check your gains. Set them to default.
    Are you overweight on your payload by any chance?
     
  3. Biggunzz

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    I am running on phantom mode with all defaults to keep things simple. Only payload is a go pro on a static mount.
     
  4. Hughie

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    Prop guards fitted ?
     
  5. Biggunzz

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    Yes. Prop guards fitted. I don't believe this is a case of prop wash or anything like that. It only happens once all three conditions are met. Throttle down, pitch forward and yawning left or right. With the latter input causing the twitch.
     
  6. noiseboy72

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    It could be the onset of VRS, but I think it is more trying to do 3 things at once.

    If you think about it, you are decreasing power on all 4 props, then pitching forward - which requires a reduction in the front props and compensating increase to the rears, and THEN you are wanting to yaw, which requires either the CW or CCW props to be decreased in speed. This really is asking a lot of the flight controller and is similar to the drifting issue some complain of if yawing and attempting to climb or descend at the same time.
     
  7. QYV

    QYV

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    I have similar behavior... when I'm descending at full throttle I tend to keep some lateral movement, but if/when I switch from front/back to left/right my Phantom does a little "wiggle" in the air and needs a second to stabilize.

    I also think it's the onset of VRS but the Phantom "catches" itself.
     
  8. N017RW

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    Not sure of the current firmware rev., as I'm a rev. back, but at some point or amount of left stick down the pitch, roll, and yaw are disabled I believe or two of the three, etc.

    Maybe you are entering/exiting this situation and thus is the twitch you see.
     
  9. QYV

    QYV

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    correct... also this
     
  10. Biggunzz

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    Y'all may be on to something....Take a look at the video...Sorry for the quality. but you can see that when I interject the yaw, the copter levels out like the yaw and tilt are canceling each other out
    [​IMG]
     
  11. Biggunzz

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    Where can I read more about this situation in regards to the firmware limitation
     
  12. N017RW

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    Sorry I can't locate anything immediately but there are enough folks here so possibly someone else will have or find it.

    But its easy enough to test in-flight.

    Try it.
     
  13. lake_flyer

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    It's one of the things in the latest firmwares that annoys me pretty much.

    The P2 (and P2V+) will go into auto landing mode when you have the throttle stick in the full down position for more than a few seconds. It will stop very abruptly with forward motion and will not accept yaw input. Keeping the stick down, the Phantom will land on the spot where it is. It descends with the maximum of 2m/s and the last 30 feet with 0.6m/s. It will automatically land and shut off when you keep the stick down (or throttle lock on newer versions).

    This is probably nice for beginners who never have flown before and probably not even have read the manual. But for experienced pilots it's terrible. I always come down in a glide slope. With the FC40 I just keep the stick down while maintaining forward pitch. That way you can come down on the way back, not losing time while descending, and keep the quad out of a VRS situation. Unfortunately, with any P2(V+) you can't do that anymore. Unless you settle with 1.5m/s and constantly keeping the throttle stick just above the point where it goes into autoland. It is just crazy when you fly with 12m/s while descending and suddenly the Phantom stops really hard, with a bang, the gimbal gets a smack, footage of a otherwise smooth flight ruined. It's quite hard to find the sweet spot with the throttle stick and not getting into BANG! FREAKING AUTOLAND

    I keep my FC40 mainly because I hate the NOOB limitations DJI imposes on ALL of us with all the other P's (except P1).
     
  14. QYV

    QYV

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    my P2 does not go into "autoland" when I hold the throttle stick full down. I'm on the latest firmware. It DOES seem to suppress yaw movement, but I can move laterally all I want, and if I release the throttle stick, it stops descending (it doesn't continue in auto-land)