Flying Qualities Analysis and Piloted Simulation Testing of a Lift+Cruise Vehicle with Propulsion Failures in Hover and Low-Speed Conditions

The recent emergence of electric-Vertical Take-Off and Landing (eVTOL) vehicles for Urban Air Mobility (UAM)
applications has resulted in a wide variety of configurations with unique stability and control characteristics. NASA
is currently conducting research to develop conceptual design tools to accelerate public acceptance of these vehicles
which includes requirements for safety during failure scenarios. This paper summarizes progress toward a toolbox for
predicting flying qualities of eVTOL vehicles during critical propulsion failures that could impact the allowable design
of the vehicle geometry or control system. Key topics include unique vulnerabilities of eVTOL/multirotor vehicles to
propulsion failures, relevant flying qualities design metrics, and simulation modeling requirements for assessing flying
qualities degradation due to failures. Results of a piloted simulation study conducted in the NASA Ames Vertical
Motion Simulator (VMS) are presented. The VMS experiment was designed to assess and validate key handling
qualities and safety design metrics for propulsion failures. These results show the correlation between control system
design requirements and the degradation in handling qualities for various propulsion failures.