Experimental and Computational Aerodynamics of a Novel E-VTOL Aircraft with Distributed Underwing Ducted Fan Propulsion

The novel eVTOL aircraft proposed in this study represents a 5-passenger short range aircraft utilizing distributed underwing ducted fans in combination with a specially designed undercambered airfoil presented as the “Maldonado-Hicks” airfoil. The design of this airfoil is hypothesized to be superior to fans mounted over the wing or on nacelles through its ability to partially hide the fans from forward flight. This effect is expected to reduce the form factor and drag generation of the wing, while also serving as a pre-inlet for the ducted fans. A hypothetical steady-state mission analysis was completed to establish the energy requirements of the aircraft. Based on the power and energy calculations, the eVTOL aircraft was estimated to require 270kW-h of energy to attain a maximum range of 290 km. Geometry modifications to the novel airfoil were conducted along with a series of 2D CFD simulations to create an airfoil family for evaluation and utilization in the eVTOL aircraft design. Additional CFD simulations were conducted consisting of a half-body aircraft model at cruise conditions in a small-scale case at Mach 0.22 and 0.13, respectively. The CFD results from the small-scale case will be used for verification of data obtained in future prototype wind-tunnel testing. The aerodynamic lift and drag coefficients were calculated and plotted for these CFD simulation cases to evaluate the aerodynamic efficiency of the aircraft. Results revealed that the Maldonado-Hicks airfoil reduced the drag force of the wing; however, the airfoil also exhibited a reduction in lift generation that may negate the benefits to the aerodynamic efficiency gained by the airfoil design. Future work includes wind-tunnel testing of the small-scale aircraft prototype as well as further high-fidelity CFD simulations of the eVTOL aircraft with the ducted fans fully simulated.