This paper introduces two innovative concepts for variable arms designed for a quadrotor, enabling precise control of its movement through manipulation of the bending moment via varying arm lengths. The primary objective of this research is to develop and identify the most suitable variable arm configuration that facilitates smooth and stable quadrotor movement. The study delves into two concept designs that are well-suited for the quadrotor application. By employing a suitable variable arm, the quadrotor’s maneuverability can be effectively regulated based on the bending moment adjustments made possible by the variable arm. Ultimately, the paper presents the design and performance testing of two types of variable arms. The obtained results confirm that the variable arm of the electric actuator with linear guide-Type 2 exhibits smooth and stable movement.