Y6 Extreme Yaw Issues

I'm sure this is something that I am simply overlooking but rebuilding and searching for a fix has left me without an answer.  Hoping some of you experienced with the Y6 can point me in the right direction.

The frame:

  • APM 2.5 - Firmware Y6 v3.0.1
  • Internal Compass
  • Old uBlox w/out Compass
  • 880Kv motors spinning 11x4.7 props
  • Motor Directions:
    • 1 - CCW
    • 2 - CW
    • 3 - CCW
    • 4 - CW
    • 5 - CW
    • 6 - CCW
  • 3s 5000mAH LiPO

All seems to be functioning properly, the motors all respond properly to the CLI tests.  The props are all spinning in the right directions.  Compass is right on and responds well as well as all the of other sensors from what I can tell.  The radio is calibrated and not trimmed.

The Issue:

When I attempt to take off the frame starts to violently spin in the clockwise direction regardless of left rudder input.  It seems that it will in fact take off, but will not be in control in terms of yaw.  It will just spin faster and faster.

I can change the direction of the spin by applying full right rudder (the direction of the spin), which immediately stops the clockwise spin and starts a counter-clockwise spin.  At no point can I reach a neutral hover.

I have re-flashed the firmware.  Recalibrated the sensors / ESCs.  Checked and double checked the ESC signal wires and they are all as specified in the Y6 manual.

Anybody have any ideas on where to start?  I am fresh out of things to try.

Cheers,

Mike

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Replies

  • UPDATE:

    So this is interesting.  Opened MP today and there was an update...  so I applied it and reflashed the copter.  Low and behold I just went a flew a stable Y6 for the first time.

    The flight had all kinds of issues due to an idiot operator (me) re-mixing the flight modes and flying in loiter versus stabilize but outside of that it was controllable.  I am charging my packs and headed out to get more logs to compare with the original logs I posted to see if there was anything glaring different.  I will post them as soon as I get them.

    Thanks for all of your ongoing help!!  

    Cheers,

    Mike

  • From watching (and listening) to the video it seems that there is not much correction being done by the autopilot to control the yaw.

    I was also wondering if maybe the bottom props were flipped upside down (the writing must be facing the top of the aircraft), but this would make a huge amount of noise when it got enough power to get in the air.

    Im not an expert are reading logs so cant really help you there.  Only thing I can suggest is to disconnect all of your APM connections and start over going through them 1 by 1 and using the mission planner to make sure everything is functioning correctly.  I have beat my head against the wall only to find out that I had one connection wrong.

    Best of luck

  • Please turn on all logging and record this behavior - only way we can help.

  • Hi Mike. Might be a silly question but are you sure you have 3 normal props ans 3 pusher props?
  • UPDATE:

    I have swapped the rear props so that they are symmetrical (all the tops rotate CW and all bottoms rotate CCW) and it made no difference what so ever.  Instant uncontrollable yaw to the right which cannot be countered no matter how much left rudder I give it.  

    Rudder inputs are correct, props are spinning properly, compass reads correct.  

    Here is a vid of the effect in action:

     

    As you can see, its ugly...  unflyable in its current state.  Any ideas?

  • It should fly with your setup, so it is probably PID tuning.

    Check out the other threads about yaw stability and do the rear prop direction change.

    Do you have the yaw direction working properly in the transmitter?  IE: is the rudder channel reversed?

  • That happened to me also. I found I had all the lower motors reversed. The build instructions indicate the direction looking DOWN from the top. In the engineering world motor rotation is indicated when looking at the shaft which is opposite of this case. Good luck, Jim

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