Spatial All-Wing Configuration for the Conceptual Design of VTOL Solar-Powered Aircraft

To mitigate the reliance on runways of conventional solar-powered aircraft and unify long endurance with deployment flexibility, this study proposes an innovative "Spatial All-Wing Configuration" concept for vertical take-off and landing (VTOL) solar-powered aircraft. Three representative layouts, namely closed, semi-closed, and open configurations, are evaluated through a quantitative analysis of aerodynamic and energy harvesting performance suitable for the conceptual design phase. The Vortex Lattice Method (VLM) is employed to quantify the impact of key layout parameters on aerodynamic characteristics, while a three-dimensional shading model integrating the Keidel irradiance model and polygon clipping algorithm is constructed to accurately calculate photovoltaic energy harvesting losses. Results demonstrate that the closed configuration achieves optimal aerodynamic efficiency due to its larger effective aspect ratio. In contrast, the open configuration exhibits minimal shading loss, maintaining a daily energy loss rate as low as 1.74%, whereas the semi-closed and closed layouts suffer losses 6–18 times higher. Endurance simulations further identify a critical design trade-off: aerodynamic efficiency dominates high-altitude performance, favoring the semi-closed layouts (C-wing), while energy harvesting capability becomes the governing factor in low-altitude or energy-constrained scenarios, rendering the open H-wing the optimal choice. The proposed spatial all-wing concept and the associated analysis framework provide a significant theoretical basis and optimization path for the conceptual layout design of next-generation, long-endurance VTOL solar-powered UAVs.