Improvement of UAV's flight performance by reducing the drag force of spherical shell

In recent years, several researchers focused their work on the mechanisms to protect the UAV from the dangerous collision with obstacles particularly the application of a spherical shell. However, this mechanism has some drawbacks when used in real-world mission especially in an outdoor environment. In the presence of wind, the spherical shell will experience significant air drag that will affect the flight performance of the UAV. In this paper, we focused our study on improving the flight performance of the UAV by reducing the drag force caused mainly by the spherical shell. We analyzed its structure and components to minimize the unwanted drag force. We evaluated two spherical structure, namely the 2V geodesic and fullerene. We also evaluated the spherical shell's component so-called joint by applying airfoil shape and compared it to a flat-plate design. CFD simulation and wind tunnel experiment were used as an evaluation tool to obtain a quantitative result. Based on our evaluation, changing from flat-plate to airfoil shape decrease the drag force of the joints by 72.31 %. Likewise, changing the structure from 2V geodesic to fullerene reduced the drag force of the connections by 12.42 %. The combination of fullerene structure and airfoil joints reduced the overall drag force by 34.74 %. An actual flight test in the bridge in the presence of wind further verifies the performance of the system by using the spherical shell with fullerene structure and airfoil joint.