• *
  • 1
250 ESC rpm issues
« on: October 23, 2016, 08:29:52 pm »
Hi 250 newbie here...
 having just built the 250 clone which wasn't too bad I then interfaced it to my 450 controller Futaba T8J then went through the Libre Pilot setup for the aircraft and the controller.  During setting up the motors with the slider control I had some differences  in the slider numbers around 10-15.    which reflected in the rpm measured with a tachometer.  I then continued with the controller setup etc. First flight the thing wanted to go sideways at some speed then continued to destroy the props.  Having gone through two sets I ordered more continuing with another test flight but going for gold instead of trying to hover and get a feel for the thing.  With new props I gave it a good up command which made  lurch forward culminating into a wonderful swan dive into the concrete.  Back on the bench with props removed I measured the rpm with a tacho. With the minimum up command 1,3 & 4 were around 22000rpm with No2 at 12000rpm.  Back into libre pilot I set the motors to around 6200 rpm on each with the slider  then connected to the controller again with a slight up command again resulting in 22300rpm on 1,3 & 4.  I then swapped the  ESC connector   for 1 & 2  on the CC3D . This time the No1 motor was going slow with No2 correct implying the motor and ESC are working OK.  Could someone throw some light on to this issue as the incorrect rpm on No2 is throwing the dynamics totally to pot.  Is it the CC3D or could it be the actual Futaba T8J for whatever reason.  Oh yes  the plastic props are hopeless sheering off at the hub just looking at them :-)    atb


  • ***
  • 137
Re: 250 ESC rpm issues
« Reply #1 on: October 23, 2016, 08:52:21 pm »
May I suggest DAL props.
Also I wonder if your board orientation ( attitude page in GCS ) is correct.


  • *
  • 117
Re: 250 ESC rpm issues
« Reply #2 on: October 23, 2016, 11:16:32 pm »
Did you actually calibrate your ESCs?
I suggest you to use BLHeli ESC and configure that first. I found that straight from the vendor all ESCs have different settings, thus different starting RPMs even after calibration. If you update each ESC individually to the latest firmware (14.8 current) and set them all to the same limits and other parameters, then you will have all ESCs identical. You still will need to calibrate them together to match you controller signal limits. After doing that you will find that your copter have much lower vibration and smoother flight.

Re: 250 ESC rpm issues
« Reply #3 on: October 24, 2016, 03:38:37 am »
Hrm...curious behavior. I'd wonder if the signal from the suspected output on the CC3D is incorrect or something. Im not sure of a way to check that without an expensive oscilloscope or something.

Sent from my VS986 using Tapatalk

Re: 250 ESC rpm issues
« Reply #4 on: November 07, 2016, 07:28:17 am »
You describe motors and ESCs being basically correct, but the settings on the output page must be a lot different for that to happen.

If you follow all the instructions in the wiki on ESC calibration (including motor neutral settings) you should get it corrected.