From Hybrid to Hydrogen: Development and Optimization of Air Taxi Layout Schemes and Propulsion Systems for Urban Mobility Applications

The rapid expansion of urban air mobility (UAM) is transforming the market of short-distance transportation, offering a sustainable alternative to ground-based transit systems. The first part of this paper analyzes various propulsion system layouts and aircraft configurations that have been proposed for air taxis, emphasizing their applicability in both passenger and cargo transport. A comprehensive review of existing eVTOL (electric vertical take-off and landing) designs is conducted, highlighting the advantages and limitations of hybrid-electric and hydrogen-based propulsion systems. The study explores the integration of new aerodynamic schemes, such as tiltrotors and flying wings, with advanced energy management strategies to enhance efficiency and flight range. Next, in the second part of this paper, a hydrogen-powered vertical take-off and landing (HydVTOL) aircraft concept, named XFlight, is proposed, in two transport options. The first has a hydrogen-electric power plant inside the body, while the second option has it outside the body. The XFlight design aims to offer greater flight range, higher cruise speeds, enhanced system redundancy, and zero harmful emissions, making it a more efficient and environmentally friendly alternative to current VTOL and eVTOL solutions. The findings underscore the potential of hydrogen propulsion in shaping the next generation of UAM vehicles, offering a pathway to greater autonomy, cost-effectiveness, and scalability in urban transportation networks.