The Atto DC130, 136-R and DC165 frames run a dead cat configuration that places the rear motors closer to the centre of the frame than the fronts.
This means the front motors have further to go for a turn on the roll axis than the rear motors so require more power to do so. The same goes for yaw and pitch although it is not as noticeable on this axis. Your flight controller assumes the quad is a ‘true X’, with motors equally spaced from the centre so the initial signal sent to the motors can be incorrect with a dead cat frame.
In reality, flight controllers operate at super fast speeds and any error in the movement of the quad is immediately corrected by the software so most pilots won’t notice any difference in actual use. We’ve flown Atto quads on stock betaflight PIDS and they fly great but depending on your build you may want to do some additional tuning.
For those wishing to finely tune their quad you can run a custom motor mix in cleanflight or betaflight to tell the flight controller exactly where the motors are relative to the centre. This removes the need for correction by the flight controller and makes the quad easier to tune as if it’s a true X configuration.
Setting your custom motor mix
The first thing you’ll need is cleanflight or betaflight software running on your flight controller. Once you have it running connect to your software and click the ‘CLI’ tab.
Choose the appropriate commands for your frame from the list below and copy the lines exactly into the CLI window.
For the 136-R type:
mixer custom mmix reset mmix 0 1 -0.882 0.944 -1 mmix 1 1 -1 -0.944 1 mmix 2 1 0.882 0.944 1 mmix 3 1 1 -0.944 -1
For the DC130 type:
mmix 0 1 -0.727 0.807 -1 mmix 1 1 -1 -0.807 1 mmix 2 1 0.727 0.807 1 mmix 3 1 1 -0.807 -1
For the DC165 type:
mixer custom mmix reset mmix 0 1 -0.821 0.818 -1 mmix 1 1 -1 -0.818 1 mmix 2 1 0.821 0.818 1 mmix 3 1 1 -0.818 -1
Then type ‘save’ and hit ‘enter’ and you’re all done. Your flight controller now knows exactly where your motors are and all is well. Now go and fly!