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crashed, repaired, now a horrible shudder on full throttle

Discussion in 'General Discussion' started by MILLER4PRESIDENT2020, Mar 3, 2014.

  1. MILLER4PRESIDENT2020

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    like my other post said a few days ago I had my first hard crash. Coming in to land and misjudged a branch, it hit the branch, flipped over and came down hard into concrete from about 50 feet up. It all happened so fast that I can't remember where the phantom exactly hit first but it snapped 3 of the plastic vision props, messed up my gimbal so now the tilt control doesnt work (the gimbal does though just not the tilt), go pro camera works but is beaten up. The frame appears to be all in once piece with no cracks

    i finally put the basics back on today,with the old original white props, ditched the FPV and gimbal, ran the advanced IMU calibration, did the compass dance. Took off to my suprise and hovered normally. But when I give it vertical power to climb it shudders horribly. There will be a video to come once i can get my roomate to help film. I did not start testing out forward/backward/sideways at full speed to see if it still shudders. I was concerned enough with the shuddering I was already seeing I did not want to do any more damage.

    I know there are probably a million variable but if anyone wants point out a few suggestions as to where to start it diagnosing it would help. I am thinking maybe I knocked a motor out of alignment and there isnt enough power involved during the normal hover to really bring out the symptoms, thats why it shows up during acceleration? Also my gain values are still set at whatever I changed them to for when I had the plastic vision props on it, I did not change them back when I put the original props on, nor do I even remember what the stock gain values were, but I really dont see this as being much of a cause.

    Like I said, video to come shortly.
     
  2. LandYachtMedia

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    Re: crashed, repaired, now a horrible shudder on full thrott

    The first thing to do is to pull up on each prop. If any of them move then you are missing the clip on the back of the motor. That will cause problems when pulling full thrust from the motor.
     
  3. davemcm

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    Re: crashed, repaired, now a horrible shudder on full thrott

    I have just tried this with mine and 3 seem to be completely solid and one moves slightly in every direction, including lifting up.

    How can this be fixed? What clip are you referring to?

    Thanks
     
  4. EMCSQUAR

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    Re: crashed, repaired, now a horrible shudder on full thrott

    On the bottom side of motor is a small "C" clip that has been known to slip loose, sometimes into motor seizing motor. You need to undo 4 screws on bottom side of arm and you can lift motor up enough to see if clip is there/on
     
  5. MILLER4PRESIDENT2020

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    Re: crashed, repaired, now a horrible shudder on full thrott

    just tried it and one of them moves ever so slightly compared to the other 3 which have no play at all. I mean you couldnt even measure it on a ruleer, i would describe it as a "tiny bit of upwards wiggle room" compared to the other 3.

    Guess this is my starting point?!
     
  6. LandYachtMedia

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    Re: crashed, repaired, now a horrible shudder on full thrott

    That is your starting point. Take things apart and you should find that the "E" clip is missing from the shaft of the motor. You'll need to find it in the body or stuck to the motor, or get a replacement and install it. That should solve your problem. There should also be a thin plastic thrust washer between the clip and the motor.
     
  7. MILLER4PRESIDENT2020

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    Re: crashed, repaired, now a horrible shudder on full thrott

    second theory just popped up. On the motor which I suspect is causing the problem the clamp is not missing(pics 1 and 2) but there is a decent scratch as seen in the third picture. I am not sure the exact RPM of these motors but I would imagine any imperfections in the motor would cause it to start shuddering when given full power?





    the scratch
     

    Attached Files:

  8. MILLER4PRESIDENT2020

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    Re: crashed, repaired, now a horrible shudder on full thrott

    the scratch2
     

    Attached Files:

  9. OI Photography

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    Re: crashed, repaired, now a horrible shudder on full thrott

    Looks to me like that could indeed have taken off enough to affect the balance of that motor, the effects of which would be amplified by higher RPM's.

    Maybe power up the motors individually one by one while mounted and do a throttle range test...I'm guessing that one will confirm the theory when you isolate it and spin it up.
     
  10. MILLER4PRESIDENT2020

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    Re: crashed, repaired, now a horrible shudder on full thrott

    good plan, but how do i power them up one by one?
     
  11. OI Photography

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    Re: crashed, repaired, now a horrible shudder on full thrott

    What receiver are you using? If it's stock, is it the PPM model with 1 lead going to the NAZA or the DBUS model with two?
     
  12. thongbong

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    Re: crashed, repaired, now a horrible shudder on full thrott

    Check your GPS module, a hard crash can loosen a screw. If it vibrates by the smallest degree it will give you erratic flight. Check also if your naza came loose. The smallest movement will also make it fly wonky.
     
  13. MILLER4PRESIDENT2020

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    Re: crashed, repaired, now a horrible shudder on full thrott

    its the stock receiver. I just bolted the phantom back up and I am burnt out for the night. I will check tomorrow for the number of leads. Thanks.

    But i did take all the props off and then put one on at a time and tested each one to while bolted down to see if any one motor caused more vibration than the other. A casual observation didnt yield any concrete differences.