Three-Component Aerodynamic-Force Measurement System

This project addresses the challenge of accurately measuring aerodynamic lift and drag forces in the low-speed wind tunnel of the Engineering Laboratories and Research Center at the Lebanese American University -Byblos Campus. Traditional multi-axis aerodynamic balances are costly and difficult to maintain, limiting opportunities for students to conduct realistic aerodynamic experiments. To overcome this limitation, the project involved designing, analyzing, fabricating, and validating a modular multi-load-cell measurement system capable of capturing the lift and drag forces acting on a NACA 4415 airfoil over a range of angles of attack from -30° to +30° or any other test model placed inside the wind tunnel. Building upon the work conducted in Project I, Project II focused on transitioning the structural components from 3D-printed PLA to a stainless-steel machined implementation, incorporating U-shaped pin connections in place of the original ball-joint arrangement, and introducing a spring compensation mechanism, significantly improving measurement sensitivity. The stress and deflection analyses were updated for the stainless-steel configuration, yielding a minimum factor of safety of 3.91 and a maximum plate deflection of 0.190 mm under the critical drag loading case, both satisfying the established design limits. The angle-of-attack control system was completed using a 75 mm linear actuator driven by an Arduino Mega 2560 with dual B10K potentiometer feedback, achieving positioning accuracy within ±0.5°. All six load cells were individually calibrated and integrated with HX711 24-bit amplifiers. The Python graphical user interface was conducted with real-time force visualization, shape selection capability, per-cell monitoring, adjustable moving-average smoothing, and automatic formatted report generation. The complete system is ready for wind-tunnel testing and experimental validation at the LAU Engineering Laboratory Research Center.

Project Details

[photo]