Wind Tunnel Test of a Single Electrical Lift Thrust Unit to assess Static and Dynamic Loads

Abstract

This paper focuses on the design of an experimental wind tunnel test rig to assess the static and dynamic loads generated by electrical lift thrust units in different flight conditions. Given the emerging interest of the aeronautical community in novel multi-propeller Electric Vertical Take-Off and Landing (e-VTOL) aircraft for Advanced Air Mobility, this paper aims to contribute to the definition of new methodologies and tools to assist the design since the early stages. More specifically, the study proposes an experimental setup to measure the static and dynamic loads along the three principal directions generated by an Electrical Lift Thrust Unit (e-LTU) to be used for comparison and correlation with simulation comprehensive tools. Due to the stiff propeller architecture, significant static and dynamic roll and pitch hub moments can be generated in some flight conditions, such as helicopter mode forward flight or conversion phase characterised by edgewise airflow. The same phenomenon is not normally observed in conventional articulated helicopter rotors in which the presence of the blade hinges reduces the moment hub loads.