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DeveloperPermalink Reply by jasonshort on September 18, 2011 at 12:16pm

I've never had this problem before, but I've heard about it from others. I think it's an uncalibrated compass.

Fly around a bit and then disarm the copter. Disarming will save the compass calibrations.

If you want to verify it's the compass, disable it in the CLI Setup menu. "Compass off"

Jason

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Permalink Reply by Don Cramer on September 18, 2011 at 12:30pm

I have seen this before in one of my quads and posted about it. I was playing with PID's trying to get rid of the 'springy' yaw i still see today.. When i had the yaw stabilize P down to low all i had to do was a bit of forward flight in any direction and the yaw would spin 90-180 degrees or more. I reverted P to higher value and it went away, wierd. I cant explain it and have not sen it sense (but never lowered my P since).

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Permalink Reply by CyberCrash on September 18, 2011 at 12:35pm

Hello,

just my two cents:

 

1. I had motors just like yours once. Even the prop holders looked like yours.

 

Problem: This setup makes the motor shaft very long. So if the shaft is even a tiny bit unbalanced this will have a huge impact on vibrations. I had exactly this problem. My copter (about one year ago it was a Mikrokopter) wouldn't fly in a streight line.

Different motors with a differnt prop holding system: problem solved

 

2. In your video I hear a really loud, strange sound as soon as you try to fly forward. Maybe there is just something wrong with your front-left motor.

...just a guess

 

I hope you can solve the problem.

Kai

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Permalink Reply by Michael Pursifull on September 18, 2011 at 3:36pm

You do have a magnetometer installed, yes?

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Permalink Reply by Michael Pursifull on September 18, 2011 at 3:44pm

Your video says compass... but maybe something is not working? And when GPS speed gives a vector, it rotates? 

 

I also wonder about the balance of your props; odd noise and you can see the motor being wobbled from the sticker movement, mostly on the right, but also a little on the left prop in the video. 

 

Congrats on the good flying. Pretty good video. 

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Permalink Reply by Henri Siik on September 19, 2011 at 8:47am

Actually the motors don't wobble, checked it with ac secured to table. The wobbling is jello effect in video due to slight frame vibration. Yes, magnetometer is installed.

 

Any suggestions for prop holders? Ones i use now are stock holders that come with arducopter motors with aluminium cone replaced with nylok-fasteners.

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Permalink Reply by Henri Siik on September 20, 2011 at 5:06am

Ok, changed one of motors and tweaked yaw stabilize P back and forth, it seemed to be ok, but...

Uploaded this vid, almost lost the copter, whew...

http://www.youtube.com/watch?v=3L45iai21mk

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Permalink Reply by Michael Pursifull on September 20, 2011 at 3:34pm

Sorry, I have almost no yaw tuning experience. My only yaw problems came from not reading the manual and flying without a magnetometer. From that experience, I test my compass to make sure I did not install it upside down, or front-to-back, and I use the Cli to verify that I am getting good data from it, then I use a physical compass to make sure the quad knows which way is north. I check approximately also as part of my pre-flight check because twice I have seen it reverse directions 180 for reasons I cannot explain. I moved the quad about 5 feet, restarted it, and it was normal again. I had a theory about magnetic interference during boot, but I do not know if that theory holds water.

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Permalink Reply by Henri Siik on September 25, 2011 at 3:21am

Magic. I uploaded 2.0.44 and everything works. Perfect. :)

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