The screws of each rack must be tightened.
The chassis and PCB at the bottom have been fixed.
Next, install four motors.
Before installing the screws, you can add some special screw glue to the screws, which will make the screws more firmly installed.
Next, install four electric keys.
The flight controller and receiver are wired.
Weld the electric wire of the electric regulator and the battery wire to the PCB. Do not weld the positive and negative electrodes upside down.
Install the flight controller and receiver on the printed circuit board.
The power management module is also installed on the PCB.
The wiring of flight control lines and redundant lines should use tie straps.
Finally, the GPS module and blades are installed to assemble a small four-axis multi-rotor UAV.