U8 large quad



After months waiting for motors and props, we finally managed to put our large quad up in the air!


It flies up to 56min and can currently carry nex 7. next one will be with zenmuse 5D! can't wait!


It was pretty difficult to get the right setting as the 29" props run very slow on those 135kV motors.


The copter flies really like a big truck! quite nice!



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  • Hi,

     I wonder if you could share your PID settings for the large quad.


  • 3701709041?profile=originalIn BLHeli you can set all parameters,most important is Demag compensation,

    Damping force and Motor timing

  • I also did autotune with 15x5 props on 6S same 400KV 650W motors,no problem...problem with big props and slow rotation is to have proper ESC who can handle that....with 6S 15x5 I used normal Turnigy Plush 40A,no problems..with 4S and 18x5.5,motor gave me strange sounds and that disappeared when I flashed Plush 40A with BLHeli firmwere(similar like SimonK but better for pancake motors with 22poles) here is all about BLHeli



    now I am still testing that combination before I will attempt autotune.....

  • 380kv and 14" = autotune no problems. It was pretty far out (over tuned), but it did at least complete the program.

    Way I see it - big props need more torque to respond to acceleration requests. If your motor can't deliver that torque, you'll have issues, and probably long before you attempt autotune. Power gives you lift, but torque gives you control.

    Cue corrections to this statement in 3...2...1....:-)


  • What a nonsense that APM cant handle bigger props...No problem with 400KV motors and 18x5.5 props and APM...autotune I did not try

  • T3

    No problem with autotune and 17'' props, crash with 18'' props...

  • T3

    I am playing with two different types of motors and always try to keep it hover at 50% throttle*. So that should not be the problem. Maybe there is some difference between a quad and a hexa? But I observed no differences between high frequency IMU logging and default. So this should not be the case. I'll play a little with the PIDs and see.

    *with 18'' props and hover at about 30% throttle the copter is almost uncontrollable. 

  • I too keep seeing reference to issues with large props. In general, there seems to be a view that larger props are less responsive. I have never seen any data to support this. I currently use 16x8 props but I have a set of 17x8 that I have used with no problem at all (AUW 5.16Kg). As far as I can see, large props correctly matched to a motor should not be a problem at all. If you arbitrarily change out your props for larger ones without regard for how well they are matched to the motor then I could well image that the results wouldn't be too flash.... 

  • T3

    Autotune worked fine with 15'' and 16'' props. I haven't tried it so far using 17'' (I first have to balance the props. There were heavy visible vibrations of the arms but it was pretty stable in loiter anyway). I'll try a Pixhawk with the 18'' props next week. Is there any explanation why the Wookong is that much better with larger probs? Is it the frequency? In this respect has anyone any information on the release date of AC 3.2(RC?) to compare 100 vs. 400Hz? 

  • Heres that comment again.   "Large Props no good for APM"...  Is that actually true or is it just settings need more carefully configured? Then APM2.6, Pixhawk ??  On another thread Gary mentioned Pixhawk is as powerful or if not more than other commercial offerings..plus it has a very dedicated dev team. Im curious to know the largest stable copter utilising the pixhawk here.



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