Design of Miniature Wind Tunnel for Measuring Pitching Moment on an Airfoil

This project presents the design and development of a compact, fully 3D-printed wind tunnel for measuring the aerodynamic pitching moment of airfoils. The system is intended to provide an affordable and accessible platform for aerodynamic experimentation while maintaining sufficient accuracy for educational and small-scale research applications. A key objective was to create a self-contained unit capable of fitting within a confined space while achieving airflow velocities up to 24 m/s and measuring airfoil response across a +/-10 degrees angle of attack range.

The wind tunnel integrates mechanical, electrical, and software subsystems. Additive manufacturing was used extensively to fabricate components such as the honeycomb flow straightener, test section, and sensor mounts, reducing cost and enabling rapid iteration. The system is controlled using an Arduino Uno R3, which interfaces with LabVIEW for real-time data acquisition and control. Sensors include a hot-wire anemometer for airflow velocity, a rotary encoder for angle of attack, and a torque sensor for measuring pitching moment. A stepper motor adjusts the airfoil orientation, while a fan driven by an electronic speed controller regulates airflow.

Experimental results demonstrate the system's ability to capture pitching moment trends as a function of angle of attack for different airfoil geometries, including symmetric and cambered profiles. Observed data aligns with expected aerodynamic behavior, such as zero pitching moment at zero angle of attack for symmetric airfoils and nonzero values for cambered airfoils. Overall, the project delivers a low-cost, modular, and scalable wind tunnel design that supports aerodynamic education and experimentation.