Optimization the design to provide ample installation space for various flight controlled system. Equipped with gimbals mount, the boom adopts inward and lateral inclination design, which can make the aircraft more stable in roll and pitches directions and flexible in rotate. Adopting integrated Printed Circuit Board wiring and equipped with strengthen 5um composite Printed Circuit Board, electrical adjustment and other wiring faster and safe. Four force arms are craft from nylon and carbon fibered rod, each arm is reinforced with a whole carbon fibered rod. The new design is lowered the installation position of the motor and raised the Printed Circuit Board position, making the center of gravities of the new four aircraft lower and more stable.