Development and Calibration of the AERTS II Rotor Icing Test Stand

A new Adverse Environment Rotor Test Stand (AERTS II) facility was designed and constructed to investigate rotor blade icing phenomena and evaluate ice protection technologies under controlled rotating-frame conditions. The facility consists of a 350 hp (261 kW) direct-drive rotor and spray system in a walk-in freezer capable of producing controlled FAR Appendix C and Appendix O icing clouds for rotor diameters up to 22 ft (6.7 m). This work presents the facility configuration, calibration approach, and initial icing results. A liquid water content (LWC) calibration methodology based on rime ice accretion thickness was implemented to determine experimental LWC and establish repeatable operating procedures. Ice shapes from a NACA 0012 paddle blade were compared against LEWICE-based predictions, repeatability cases, and published reference wind tunnel ice shapes. Repeatability testing showed good agreement between runs, particularly in colder icing regimes, with maximum variations of 15.75% in cross-sectional ice area, 1.33% in impingement limits, and 15.12% in stagnation thickness. These results demonstrate AERTS II's ability to reproduce representative rotor icing conditions in a controlled indoor environment. The facility also demonstrated support for wirelessly controlled rotating-frame electro-thermal heater experiments, establishing AERTS II as a novel platform for rotor icing physics investigations and rotorcraft ice protection system evaluation.