Description: Advanced air mobility (AAM) seeks to develop a large-scale transportation system to revolutionize how people live and work in this century. Electric vertical take-off and landing (eVTOL) aircraft will form a central part of the AAM infrastructure due to reduced emissions and noise impact. An important aspect for eVTOL aircraft certification is safe urban operations, which requires understanding of the response due to aerodynamic disturbances. Experimental data are required to support eVTOL aircraft development with respect to flight dynamics and controllability, as well as design specification development. To this end, Continuum Dynamics, Inc. with teaming partners Pennsylvania State University and Alaka'i Technologies proposes to develop a subscale testing methodology for assessing eVTOL aircraft disturbance response / rejection characteristics including validation with similar data obtained for full-sized aircraft flight tests. In Phase I, scaling relationships for flight dynamics/control, aerodynamic interactions, and propulsion-airframe integration will be identified from comprehensive analytical models. A subscale dynamic model will be fabricated and tested in an indoor facility to quantitatively measure response characteristics in aerodynamic disturbances. Subscale data will be compared with model predictions and available full-sized vehicle data, which will be used to form experimental test plans for execution during follow-on work.

Benefits: Successful development and demonstration of a dynamically-scaled free-flight test methodology will have numerous benefits and significant commercial opportunity. Development and validation of subscale testing procedures will allow data to be collected of both aerodynamic disturbances created by wind flow around urban vertiports/buildings and vehicle flight dynamics response characteristics. In contrast to full-sized testing, subscale testing provides significant flexibility to evaluate many variations of the operating environment, such as vertiport configuration and approach / departure flight paths near buildings / in "urban canyons"). These data would prove valuable for NASA internal research and development toward ARMD Strategic Thrust #1 (Safe, Efficient Growth of Global Operations) and #4 (Safe, Quiet, and Affordable Vertical Lift Air Vehicles), which has focused on flight dynamics and control, real-time simulation, and design specification evaluation.Beyond NASA applications, development of a validated subscale testing methodology could lead to a significant commercial venture through testing services as part of eVTOL aircraft flight qualification. Experimental data are needed for AAM aircraft certification, and if shown to capture key phenomena relevant to vehicle flying qualities assessment, subscale dynamic model testing can provide a cost-effective method to evaluate a wide range of operational scenarios. To this end, CDI plans to connect with and engage multiple industry and government stakeholders, including both subscale model manufacturers and FAA personnel, during the proposed Phase I and follow-on activities to facilitate technology transition and commercialization.