The Spedix S250 is a complete wide-arm racing quadcopter perfectly suited for the Pixracer autopilot.
The hardware required for this build is displayed below.
Mounting and Wiring
Connect GPS and the Wifi module as shown in the Pixracer instructions. Connect the four motors in the layout and order as shown below, so the MAIN1 connector should connect to motor 1, and so on.
Select the QAV250 configuration as shown below. This will not only put PX4 into quadrotor mode, but also load decent default tuning gains.