Tail Vibe Assistance

Discussion in 'The Chat Room' started by gonehelimad, Dec 6, 2016.

By gonehelimad on Dec 6, 2016 at 8:43 PM
  1. gonehelimad

    gonehelimad Active Member

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    Okay summary is im wondering if any mrchc ppl have a spare known perfectly working tail servo they can lend me for quick troubleshooting via bemch test at club.

    Mini servo or bk7005 with mini cover.

    Here is my storey.

    After my last crash with my align 500l beater (use this little rascal as my learner) ive been plagued with an inconsistent tail wag that i cant get rid off during flight causing bouncing of tail and weird tail interactions and during hover random tail wag. Been chasing for 2 months

    Ive worked through the heli systematically as follows checking during spooled up heli after each

    Replaced thrust and main tail bearings
    Replaced tail rear umbrella shaft gears
    Replaced torque tube and tt bearing
    Rwplaced rear boom box gears
    Replaced main gear
    Replaced shaft
    Replaced motor bearing and motor shaft
    Rwplaced shaft bearings
    Replaced tail servo gears just in case

    Vibes there without main rotor housing and blade grips installed so didnt touch these

    Freeed up wiring so its not touching body
    Swapped gyro for known perfectly working gyro.

    Have recently installed hw 100a v3 plat pro so esc is new. Setup gyro in throttle curve (no gov)

    None of the above has helped.

    Im suspecting maybe its the tail servo pot.
    Currently its a bk7005. Didnt go this way as only at high head speed on bench does the tail servo start to exhibit unsmooth motion during left and right throws.

    Hoping someone can loan me while at club a working servo i can use to rule out the servo.

    Not sure what else i can do after that.


    Thanks
     
    Last edited: Dec 7, 2016
    gonehelimad, Dec 6, 2016
    #1

Comments

Discussion in 'The Chat Room' started by gonehelimad, Dec 6, 2016.

    1. maingeer

      maingeer Active Member

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      Did you sort this out yet dude? I got a spare KST 515MG, is that ok? but I'm not part of any club.
       
      maingeer, Dec 10, 2016
      #2
    2. gonehelimad

      gonehelimad Active Member

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      Not yet

      Sent from my SM-G928I using Tapatalk
       
      gonehelimad, Dec 10, 2016
      #3
    3. maingeer

      maingeer Active Member

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      I'm on the west side close to the MARCS club, but not part of it. It may be a bit of a hike let me know, unless you want to wait it out for someone closer to you
       
      maingeer, Dec 10, 2016
      #4
    4. gonehelimad

      gonehelimad Active Member

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      msged you
       
      gonehelimad, Dec 10, 2016
      #5
    5. icanfly

      icanfly New Member

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      find the prob? I had a similar experience with a smaller heli where the motor was out of balance and drove the tail nuts, me too until I took the blades off and spooled it up held it in my hands and felt where the vibes on the heli were not caused by blades and shafts necessarily. You may have bent a motor shaft.
       
      icanfly, Dec 12, 2016
      #6
    6. gonehelimad

      gonehelimad Active Member

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      Tested a known working servo on weekend and vibes still there same as before..

      Motor can out of balance i think. New motor on order

      See here


      Hope this solves it
       
      Last edited: Dec 12, 2016
      gonehelimad, Dec 12, 2016
      #7
    7. icanfly

      icanfly New Member

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      sorry. I do see you changed motor bearings and shaft. You have a tail WAG, could be from the slider binding, ball links binding, loose grip bearings, loose servo gears, worn splines on the servo arm, loose servo on chassis, binding links on the slider forks, loose hub, tail case pushed in too tightly against tt.

      Mystery problems suck.
       
      icanfly, Dec 12, 2016
      #8
    8. MickyD

      MickyD Well-Known Member

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      Binding is the biggest problem. I have had slop and the tail hold no problem, so I don't think that's the issue. Put the tail together set by step and check for binding. Make sure the grips pull out evenly. Also don't wrench in the rotor hub grub screw.
       
      MickyD, Dec 12, 2016
      #9
    9. gonehelimad

      gonehelimad Active Member

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      Thanks all for response.

      I am very systematic when it comes to tail vibes.

      As you will note most everything has been worked through starting from tail end back to front of heli. Most elements were chamged due to last crash.

      Where i am at at moment is that i only have motor gyro receiver and tail servo plugged in and operating. The only vibe producing element is the motor. Ie main gear and head are not installed / were removed.

      Swapped servo out and gyro out both for known working options and vibes persist. Im talking about jittering of servo on bench not a flight related wag.

      Servo only jitters at high headspeed.

      Took motor off frame and problem dissapears as gyro doesnt see vibes.

      So i have concluded it is the motor being out of balance. Most likely the cover/ can that spins or a stator has moved.


      Will let you know when i put new motor in.
       
      Last edited: Dec 12, 2016
      gonehelimad, Dec 12, 2016
      #10

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