Cruise aerodynamic performance of a strake-wing tail-sitter UAV

Abstract

A tail-sitter vertical take-off and landing unmanned aerial vehicle (UAV) for low-altitude interception requires vertical launch capability together with efficient fixed-wing cruise. This study assesses the cruise aerodynamic feasibility of a 30 kg strake-wing concept using three-dimensional steady Reynolds-averaged Navier-Stokes simulations. The configuration has a full-wing reference area of 0.46 m2 and uses a clipped-delta main wing, a highly swept strake, and a NACA64A-010 symmetric airfoil. Ma = 0.3 is treated as the design cruise condition, and Ma = 0.6 as the maximum-speed target. A conceptual thrust-to-weight ratio of 1.5 defines a reference installed thrust of approximately 441 N for preliminary thrust-drag assessment. At Ma = 0.3, the required lift coefficient of 0.106 is reached at α = 0.67°. The corresponding drag coefficient is approximately 0.089, giving a full-aircraft drag of approximately 246 N. The cruise condition satisfies the lift-balance and thrust-drag criteria relative to the reference installed thrust. At Ma = 0.6, the required lift is reached near α = 0.15°, but the calculated full-aircraft drag of 835 N exceeds the reference installed thrust. High-angle-of-attack calculations are used to characterize separated-flow evolution qualitatively. These results support the cruise aerodynamic feasibility of the baseline concept and identify high-speed drag reduction as the principal requirement for achieving the Ma = 0.6 target.