Comparison of Performance and Blade Loads Analytical Predictions with Wind Tunnel Measurements of a Joby Aviation eVTOL Propeller

In 2023, Joby Aviation conducted a test of a prototype propeller for an electric vertical takeoff and landing (eVTOL) tilt-propeller aircraft in the 40- by 80-Foot Wind Tunnel at the National Full-Scale Aerodynamics Complex (NFAC). There were three objectives of the test: measuring 1) propeller performance, 2) dynamic blade loads, particularly in resonance, and 3) aeroacoustics. This paper is part of a trio and is focused on performance and blade loads measurements and validation; two companion papers cited in the text present an overview of the test and provide details on aeroacoustics analysis, respectively. Test measurements are compared to predictions generated by a CFD-trained model called AeroRef, the comprehensive analysis code RCAS with a finite state dynamic wake model, the Helios ROAM mid-fidelity blade loads solver coupled to RCAS, and OVERFLOW CFD coupled to RCAS. For performance, the AeroRef model and CFD were able to accurately predict thrust and rolling and pitching moments. RCAS was able to accurately predict structural dynamic modes and resonance crossings, but test measurements showed stronger modal responses than the dynamic inflow model was able to excite. Coupling RCAS with OVERFLOW resulted in excellent predictions of dynamic blade loads but at high computational cost; ROAM-RCAS coupling provided conservative predictions with a more efficient solver, demonstrating itself as a good option for eVTOL design studies.