Time- and Energy-Saving Potentials of Efficient Urban Air Mobility Airspace Structures

Abstract

Novel electric propulsion technology has given rise to thinking about urban air mobility in a new way with its expected high degree of operational flexibility. The designs of electric vertical takeoff and landing configurations are determined by their mission profile, which we found to be oversimplified at many points in the current scientific literature. There is a gap of understanding in how mission profiles impact travel time and energy demand. In this paper, we review various mission designs, formulate a five-segment flight profile (including vertical ascent, climb, cruise, descent, and vertical approach), and apply it on a fleet level of up to 200,000 urban air mobility trips. The demand data originate from the Upper Bavaria region study, OBUAM. In a sensitivity study, we vary the cruise altitude, the height of the vertical flight segments, and the climb and descent angles for two vehicle configurations: a fixed-wing tilt-rotor concept, and a multicopter concept. The main findings for the fixed-wing concept are that the height of the vertical flight segments and the cruise altitude should be as low as possible, and small climb angles (below 7 deg) should be avoided. The multicopter concept, however, is penalized by fast forward flight while being comparatively insensitive to both the cruise altitude and height of the vertical flight segments. Furthermore, we found a tradeoff between time- and energy-optimal flights with the a energy-optimized climb/descent angle at around 10 deg.