I have built a S550 Hex running Sunnysky 3108 720kv motors.  I have a UBEC in channel 8 and all ESC's have all three wires connected to the Pixhawk. My Pixhawk is brand new.

The Spider 30A ESC's calibrate fine and do not exhibit any throttle issues in the calibration mode, I have heard a short grinding noise from one of the motors which leads me to think I may have a sync issue as well?

When I arm the Pixhawk and throttle up, the throttle doesn't respond to my input but instead starts a slow ramp up that doesn't seem to be responding to any of my adjustments, just a slow ramping up. 

I am getting very frustrated trying to get any ESC's to work with my Pixhawk. I have tried generic simonK ESC's, HobbyKing 20A UBEC ESC's and now these Spider OPTO ESC's, all of them have calibrated fine only to exhibit a variety of sync and throttle issues when armed. 

Any advice would be greatly appreciated. 


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  • I had Maytech ST 30A opto's that would not spin 6 motors. During ESC calibration they worked fine, but in RC mode the motors sounded very sick, probably similar to as described by the OP. I ran some tests, thought I found two (!!) bad ones, got them replaced and it still did the same thing.

    I then tried an old 3DR 20A in place of one of the Maytech......motors spun up great so thought maybe I found the "real" bad ESC. However, it did the same thing on every ESC. For whatever reason, the copter would not spin up 6 motors using those Maytech ESC's.

    I then returned all 8 Maytechs, bought some KTW Spyder 30A opto and thought the problem was resolved, but the motors still didn't sound right. It now has HobbyWing XRotor's and so far all is good. HobbyWing has been my choice every since.

    KDE 2814XF-515 motors.

  • With opto esc, you have to provide 5 volts on the "servo side" to power the LED of your ESC "opto side " (most of the time)

    So insure you have a voltage in between the top row marked "-" and the middle row marked "+" of the pixhawk. on the ESC side.

    I do have a number of "pixhawks" and they all work fine with Turnigy dlux speed controllers. (Standard or opto)

    Hope this help.


  • "When I arm the Pixhawk and throttle up, the throttle doesn't respond to my input but instead starts a slow ramp up that doesn't seem to be responding to any of my adjustments, just a slow ramping up."

    Do the ESCs have a slow-start feature? I bought some HK blue's which had this on by default before I flashed them with Simon-K. You would stab the throttle and they would slowly ramp up. I believe it is used for mechanical drives or aeros to reduce loading on the drive train.

    • I don't believe the Spider 30A OPTO ESC's have this slow start feature. I'm still no where in getting this problem solved :(

    • Tim,

      Did you ever resolve this issue? You arent the only one having issues with pixhawk and Spider Opto ESCs on a hexacopter. I have a similar setup to yours and have experienced the EXACT same problems you have described. Have also done all the troubleshooting with calibrating, settings, etc. with no success. I gave up months ago and ended up putting a Naza Lite on the Hexa and it has worked flawlessly the past few months. 

      I also have an X8+ I got directly from 3DR and it has been great for the 8 months that I have had it. However  after recently doing an Arducopter update I started having similar throttle issues that I had before with the Hexacopter mentiond above. After doing all the calibrations, checking the settings, etc. I was still having similar throttle issues with the X8+. So i went ahead and put an older version of ArduCopter back on Pixhawk and after doing that, the X8+ is back to working flawlessly!

      So today I am gonna take the naza off the hexa and give Pixhawk a shot again with the older version of ArduCopter (an early version of 3.2 from 8 months ago) and see if it takes care of the throttle problems like it did on the X8+. I will let you know if it works out.

    • Almost all ESCs have a slow throttle up feature, it is set using the beeps if a programmer is not available
  • Hello,
    Do you have your channel asign ment set up correctly?
    Does the ESC work as expected when connected directly to the RX is your Throttle responsive ?
    • I'm using a Turnigy 9X with a FrSky XJT JR module and a FrSky X8R receiver using the SBUS connection. When I do an all at once calibration, through the Pixhawk, I get perfect throttle response on all ESC's. I'm not sure if this what you are asking? 

    • Hi,
      do all your other channels match up when you calabarate the radio In MP? Because your using subs your radio must also be configure properly. Make sure you turn off mixing extra ?

      Did you go over this stuff?
    • Thank you so much for your help. I have not used the Wizard, I have used the manual mandatory route. My RX calibrated just fine. Where do I find "mixing extra"? 

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