Design, calibration and experimental validation of the terraXcube icing wind tunnel

This work presents the terraXcube Icing Wind Tunnel (IWT), a removable open-jet system integrated into a large environmental chamber and developed for controlled Uncrewed Aerial Vehicle (UAV) icing tests. The chamber provides independent temperature and pressure control down to −40 °C and up to an equivalent altitude of 9000 m. The tunnel was characterized over airspeeds from 5 to 20 m/s and generated Liquid Water Contents (LWCs) from 0.1 to 14 g/m 3 and Median Volume Diameters (MVDs) from 14 to 37 μm. The resulting LWC–MVD domain covers substantial portions of the icing envelopes defined in EASA CS − 29 Appendix C. The region 1–2 m downstream of the outlet was calibrated using SAE ARP5905 as the reference standard. All evaluated thermal and cloud parameters met the applicable criteria, with an average LWC uncertainty of 9% and an estimated MVD uncertainty of 12%. The aerodynamic field was the main limitation of the open-jet configuration, as the ±2% velocity-uniformity criterion was achieved only over a limited area. Facility-specific thresholds of ±10% for velocity uniformity and 10% for turbulence intensity were therefore adopted, defining usable test volumes of approximately 0.33 m 3 at 5 m/s and 0.25 m 3 at 20 m/s. The calibration was extended to object-level validation through 32 icing runs on a 15-in. propeller under rime and glaze conditions. The test matrix covered LWC values from 1 to 2 g/m 3 and MVD values from 25 to 35 μm and characterized both propulsion-system performance and ice accretion in terms of endurance, ice mass and three-dimensional ice shape. Across the investigated conditions, repeatability errors for the main performance and mass metrics ranged from 8.6% to 14.1%, while repeated rime-ice reconstructions differed by 3.6% in volume. These results provide a traceable link between facility calibration and object-level icing assessment and establish a dedicated platform for low-speed UAV platforms and rotary-wing icing research.