Mechanical design and fabrication of a 3-component external balance for MAVs in wind tunnel

Wind tunnel force measurements play a significant role in the initial aerodynamic design and subsequent evaluation of aerodynamic performance of Unmanned Aerial Vehicles (UAVs). Collecting experimental data in the early design stages of these vehicles requires the use of wind tunnel balances that provide accurate data on how airflow affects the vehicle under different conditions. These measurements are crucial in understanding how aerodynamic forces impact the aerodynamic performance and stability of these vehicles, enabling engineers to optimize their designs. Consequently, this paper describes the mechanical design and manufacturing process of a three-component external balance for wind tunnel measuring forces on Micro Air Vehicles (MAVs). Specifically, the external balance is designed using three bending load cells to measure the lift force, the aerodynamic drag force and the pitching moment on a MAV vehicle with Zimmerman wing-body geometry with a small size, less than 500 mm. A measurement validation of the external balance is conducted by comparing the experimental data with previous wind tunnel tests using another external balance at the ETSIAE-UPM facilities.