Parametric Investigation of Canards on a Flying Wing UAV Using the Taguchi Method

The current work investigates the effect of canard geometric characteristics on the performance of a lightweight flying wing Unmanned Aerial Vehicle (UAV), capable of both conventional and Vertical Take-Off and Landing (VTOL) flight. The canards are sized as horizontal stabilizers to enhance the UAV's longitudinal stability and minimize trimming requirements during cruise. Using a Design of Experiments (DOE) approach and, specifically, the Taguchi method, six canards' design parameters are investigated on three different levels. These parameters are the sweep angle (?), aspect ratio (AR), taper ratio (lambda), vertical position in relation to the main wing (v(pos)), incidence angle (i(c)), and dihedral angle (Gamma). An L-27 orthogonal array (OA) is used to investigate the influence of these key design parameters using two performance criteria, namely the Lift-to-Drag ratio (L/D) and the pitching moment coefficient (C-m), at cruise conditions (designated as L/D-cruise and |C-m|(cruise)). The investigation is conducted by using high-fidelity Computational Fluid Dynamics (CFD) methods for each of the 27 configurations defined by the L-27 OA, over a range of angles of attack. Based on the CFD results, two distinct combinations are derived for maximum L/D-cruise and minimum |C-m|(cruise) using the Signal-to-Noise ratio (SNR) analysis. The optimal design parameter combinations for the two performance criteria are A(2)B(1)C(1)D(1)E(1)F(1) and A(2)B(2)C(1)D(2)E(2)F(3), respectively. Finally, the Pareto Analysis of Variance (ANOVA) technique is conducted to define the contribution of each of the six design parameters on the L/D-cruise and the |C-m|(cruise). More specifically, i(c) seems to have the most significant effect on L/D-cruise,D- whereas ? is the most important parameter for |C-m|(cruise.)