Preliminary Propulsion and Power System Design of a Tandem-Wing Long-Range eVTOL Aircraft

Abstract

Novel eVTOL aircraft configurations are picking up momentum in the emerging market of urban air mobility (UAM). These configurations feature electrical power systems and distributed propulsion architectures, both uncommon in current aircraft. As such, the design of eVTOL aircraft lies outside the bounds of current established frameworks and poses many challenges in the field of preliminary aircraft design. This paper presents a preliminary design methodology for open rotor eVTOL configurations with batteries as the power source. First, the propeller external dimensions are calculated, and then an optimised blade geometry for cruise condition is computed. Thereupon, the batteries and electric motors are sized. The design framework is then applied to an eVTOL aircraft with a design range of 400 km and a capacity of five occupants (four passengers and one pilot), focusing on the central-European market and aimed to be released in 2030. The final configuration is a battery-powered tandem-wing aircraft with 12 variable-pitch, variable-speed open rotors placed on the leading edges of the wings. These rotors rotate outboard-down and feature six blades. The power source comprises 24 solid-state lithium batteries with a nominal voltage of 500 V and an assumed energy density of 500 Wh/kg. The proposed design methodology offers the possibility of computing the necessary propeller geometry for numerical simulations in the early stages of the design, and of easily obtaining accurate estimates for the mass of the power system which can improve the overall mass estimates for the analysed configuration.

Prognostics for Lithium-ion batteries for electric Vertical Take-off and Landing aircraft using data-driven machine learning

“…For eVTOL batteries, it is expected that conservative safety margins will be considered. In [34], a conservative EOL-threshold of 85% of a nominal battery capacity of an eVTOL is considered. This eVTOL is designed for a total capacity of 5 persons with a range of 400 km [34].…”

“…In [34], a conservative EOL-threshold of 85% of a nominal battery capacity of an eVTOL is considered. This eVTOL is designed for a total capacity of 5 persons with a range of 400 km [34]. Following [34], for our analysis, we also consider an EOL-threshold of 85% of the initially measured battery capacity.…”

“…This eVTOL is designed for a total capacity of 5 persons with a range of 400 km [34]. Following [34], for our analysis, we also consider an EOL-threshold of 85% of the initially measured battery capacity.…”

Experimental Study on the Effect of Pitching Angle on Tandem NACA 0030 and NACA 4412 Airfoils

“…In addition to single wing/airfoil configuration, many insects have more than one pair of wings, for example dragonflies. This observation in nature has encouraged researchers to study tandem wings [10][11][12] . One of the highlights of the tandem wing system is the number of wings that can be added into the tandem configuration can increase the propulsive efficiency of the system.…”

A Small UAV Optimized for Efficient Long-Range and VTOL Missions: An Experimental Tandem-Wing Quadplane Drone

“…There are a few full-scale designs, and prototypes [25,26] mainly use multiple motors to hover (e.g., 6, 8, 12, or more). Existing tandem-wing drones mostly use a tilt-motor [22,27,28] or tilt-wing design [24,29]. We decided to select this type of UAV because it has no extra motor holder beams (the two wings support the motors), and it can have a smaller wingspan than a quadplane with a comparable wing surface.…”