A Preliminary Evaluation of Icing Scaling on AAM Propellers

NASA Glenn Research Center recently developed a general-purpose propeller test stand for conducting fundamental icing physics studies on electrically driven propellers in the Icing Research Tunnel (IRT). Some preliminary icing scaling evaluation tests were conducted on propellers for Advanced Air Mobility (AAM) applications using existing recommended scaling methods that were originally developed for fixed wing aircraft. Three carbon fiber propellers of 24, 28, and 36 inch diameters were used for the test. All three propellers had a NACA 0012 airfoil profile and were geometrically scaled from a radial location of roughly 40% to the tip. During the March 2023 test entry in the IRT, a simplified model size scaling evaluation was performed in a rime ice condition with the three propellers, and a LWC condition scaling was evaluated in a glaze ice condition with the 28 inches diameter propeller. In the January 2024 IRT test entry, another LWC condition scaling was evaluated on the 36 inches diameter propeller. The ice shape scaling evaluation was performed by extracting 2D ice shapes from 3D laser scans at propeller radial location of 75%. The preliminary ice shape results showed the scaling methods are effective. Further evaluation of the scaling methods is recommended over a wider range of airflow and icing cloud conditions as well as different propeller sizes and operating conditions to assess its applicability for modern propeller and open fan engine icing scaling analysis.