AC-3.1 autotune support discussion

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Frank Vitale November 22, 2015 at 7:49pm

Need advice. Sync issues were said to be an issue with large pancake low kv motors using simonk. My exp has been sync issues with those same motors only with high poll count. Those motors having low poll count i havnt had sync issues. Having said that, i havnt tried autotune with them. I have a Tarot x6 with Multistar 50 size motors with 274kv,which are rebranded Arris 288kv motors. Using Pixhawk/Flycolor 45 amp escs, 20000mah 6s batt. Flying GREAT! These motors are low poll count--12/14. 18in carbon props. As i said, flys very well. Just would like to know if autotune would be an issue. Please advise. Frank.
- Developer
  
  leonardthall > Frank Vitale November 23, 2015 at 1:44am
  
  Hi Frank,
  
  You can test for Sync issues by switching the throttle high and low. If you don't have a problem there then Autotune should be fine. And remember, if Autotune finds a sync issue then there is a very good chance that you will find the same issue during normal flight.
  - Frank Vitale > leonardthall November 23, 2015 at 2:55am
    
    LENARD, Thank you for the response. With props off, I did high low throttle changes with no sync issues. Was just wondering with the large,heavy 18in carbon props,if that would exacerbate the issue.. Frank.
    - Developer
      
      leonardthall > Frank Vitale November 23, 2015 at 3:06am
      
      Hi Frank,
      
      You do want to test for sync issues with the props on. A common approach is to turn the props upside down.
      - George Roberts > leonardthall November 23, 2015 at 10:57am
        
        Not upside -down - just swap 2 wires so they rotate the wrong way. I did my testing by hooking the ESC's directly to the receiver and testing just one at a time and holding the copter arm in one hand while playing with the throttle with the other hand. Go from zero to full throttle as fast as you can. Jump around suddenly different throttle speeds. Consider programming the ESC acceleration features at this point in time.
        
        Frank Vitale > George Roberts November 23, 2015 at 11:33am
        
        I'm thinking just swapping two wires won't have full effect, as the props just spinning backwards won't have the same thrust. I will turn them upside down and move them in one direction around like compassmot. Then I will replicate full thrust.
        
        Developer
        
        leonardthall > Frank Vitale November 23, 2015 at 1:03pm
        
        Hi Frank,
        
        That is perfect actually because it isn't the thrust that makes the difference it is the momentum.
        
        Frank Vitale > leonardthall November 23, 2015 at 1:20pm
        
        yes, I figured it was the large 18 inch carbon fiber props with the locating the weight of the props would cause the issue
        
        Frank Vitale > Frank Vitale November 23, 2015 at 6:59pm
        
        Well,success!! Because my escs are hardwired, I just moved my props around one spot. Not only throttied high-low, also as I was doing that, I would inject pitch roll very rapidly. No sync issues. Then went out for autotune. Worked flawlessly. I would like to try this testing with same large,low kv pancake motors,only with high poll count to complete my testing. So, the low poll count was successful with no sync issues!. Thank you,Randy,Lenard,Gregmaan,Craig,And George, for your being passionate enough to add your inputs. I hope this helps any with their decision making when it comes to this issue. I would still advise caution, and do the previous testing ,for safety reasons first, and second, to save grief, and the expense of an ugly outcome. Again, I applaud this forum, and the developers/members, which has made APM/Pixhawk and the rest of the prouducts,not only competitive, but way above the competition when it comes to capabilities they provide. Bravo!!!!!
        
        Frank Vitale > Frank Vitale November 23, 2015 at 11:34am
        
        I will try this tonight after work and give results tomorrow..

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AC-3.1 autotune support discussion

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