Understanding Distributed Propulsion on the NASA Tiltwing Concept Vehicle with Aerodynamic Shape Optimization
B. Pacini, M. Prajapati, K. Duraisamy, J. R. R. A. Martins, and P. He
AIAA Scitech Forum 2023, 2023
Many urban air mobility vehicle designs are under development, featuring configurations that combine propellers with wings, tails, fuselage, and additional appendages. These complex geometries introduce physical phenomena such as propeller-wing and propeller-propeller interactions. Understanding these phenomena and optimizing a vehicle design considering their effects can lead to improved efficiency throughout a vehicle’s mission. This work considers the NASA urban air mobility tiltwing concept vehicle and analyzes the performance of its wing considering varying numbers of propellers. The tiltwing’s wing is analyzed and subsequently optimized for zero to five propellers to understand the potential for wing design improvements. This work finds that the tiltwing vehicle in cruise flight does benefit from wing-mounted propellers, however the strongest improvement in efficiency is found with a single propeller at the wingtip, with decreasing benefit as the number of propellers is increased. While this work considers only aerodynamic shape optimization without structural and packaging constraints or power plant design, it provides quantitative and qualitative insight into the advantages and disadvantages of distributed propulsors in cruise flight. Additionally, this work shows that while aerodynamic shape optimization is a useful tool for improving wing performance, considering propeller-wing interaction effects leads to a negligible improvement in optimized design.