Front arms = no lift

Hello all! I’m a first time builder, but have flown a few commercially built drones in the past. I have followed several how-tos and videos on building one from scratch and thought I had everything spec’d properly for a custom drone:

  • 10x4.5 props
  • A2212 - 1400kV motors
  • DT30A ESCs
  • Pixhawk 2.4.8 (Yeah, I know NOW that it’s a cheap Chinese clone and will be replaced by a legit Cube
  • Flysky FS-i6X controller
  • ia10B receiver
  • Ublox M8N GPS

I gone through all the steps to flash, calibrate everything, etc. I did the ESC calibration a few times, just to be sure things were working as they should. It’s an X-frame, and motors ARE spinning in the proper directions.

The problem I’m seeing is everything arms as it should, but when applying a gentle throttle up, the front to arms DO throttle up, but produce no lift while the two rear arms do lift (essentially lifting the rear, but not the front). I’ve confirmed I have the right angle props on the proper motors, and all 4 ARE spinning in their proper direction. There is only a very slight weight imbalance in the front of midline, but literally about 2oz. difference when put on a scale.

The frame was custom 3D printed using PETG based on the design of the F450 HJ450 DJI frame. All assembled, the entire copter weighs in at 3lb 10oz.

Any suggestions on where I should look for either issues or solutions?

Thanks in advance!

Grab the .bin log file and host it somewhere (dropbox, onedrive and so on) the paste the link in here.
It sounds like motor and prop directions not correct. Maybe even a short video will help.

Try the mission planner motor test - in that test motor “A” will correspond to Front-Right and subsequent letters go around clock-wise.
Test motor “A” and see if Motor 1 spins, test motor “B” and see if 4 spins…


1,2,3,4 correspond to the MainOut servo connectors.

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I’ll post the .bin log files after work, but I did notice one thing that I’ve never seen on a commercial copter before, in that after arming at idle, one or both of the front motors spin in the opposite direction pretty slowly… however, if you give it a little throttle, it reverts to spinning in the proper direction and stays that way if you go back to idle. I’m not sure if that is normal or not, in all honesty.

I’ve done the motor test individually, and it does appear that all of the motors ARE spinning in the proper direction. It, however, won’t hurt to test them again… I might have 3 & 4 inverted.

Post a video of what the aircraft is doing…

Yep, that was the problem… tested over lunch… Motors B(3) and D(4) were inverted; now they are B(4) and D(3). It’s working fine, now.

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