Impact of Technology and Mission Variations on NASA Advanced Air Mobility Concept Vehicles

NASA is conducting investigations in Advanced Air Mobility (AAM) aircraft and operations, including the development of Urban Air Mobility (UAM) aircraft designs that can be used to focus and guide research activities in support of AAM. This report is an investigation of the impact of technology and mission variations on several of the NASA AAM concept aircraft: quadrotor, quiet single main rotor, side-by-side, and tilt rotor configurations, with turboshaft and electric propulsion variants for each. First, the mission and aircraft models of the baseline designs were reassessed and updated, including rotor geometry optimization, update of the rotor performance models, and disk loading optimization. For these eight designs, technology and mission excursions were performed. The technology excursions include: growth factor; weight technology factors (with and without weight reductions due to technology, including high and low calibrations); systems and equipment weight; airframe drag; rotor design blade loading; rotor profile power; turboshaft engine weight and specific fuel consumption; motor weight and efficiency; wire weight; thermal management systems design heat rejection (motor and battery); torque margin for rpm-controlled multicopter; and battery weight (installed usable Wh/kg). The mission excursions include range (together with battery weight for electric variants); reserve time; rate-of-climb to cruise altitude, with and without one-engine inoperative requirement; rate-of-climb at cruise; takeoff and cruise altitude; and tiltrotor cruise speed. Relative to the calibration cases that can be considered examples of good design practice, the impact of the weight technology factors is significant. For the electric aircraft, there is a very large impact of battery specific energy (Wh/kg), and correspondingly a very large impact of mission range. The vision of Advanced Air Mobility is driven by missions that will enable new transportation capabilities. Hence it is appropriate to compare Concept Vehicles of different lift and propulsive architectures, all designed to accomplish the same UAM mission. It is also useful however to consider specific missions that can take advantage of the strengths of individual aircraft configurations. So alternate designs were also developed for the concept vehicles: for turboshaft aircraft, longer unrefueled range, including faster cruise speed for the tiltrotor; for electric aircraft shorter range and more realistic battery weight.