Abstract

The current study presents a low-fidelity, quasi-3D aerodynamic analysis method for Blended-Wing-Body (BWB) Unmanned Aerial Vehicle (UAV) configurations. A tactical BWB UAV experimental prototype is used as a reference platform. The method utilizes 2D panel method analyses and theoretical aerodynamic calculations to rapidly compute lift and pitching moment coefficients. The philosophy and the underlying theoretical and semi-empirical equations of the proposed method are extensively described. Corrections related to control surfaces deflection and ground effect are also suggested, so that the BWB pitching stability and trimming calculations can be supported. The method is validated against low-fidelity 3D aerodynamic analysis methods and high-fidelity, Computational Fluid Dynamics (CFD) results for various BWB configurations. The validation procedures show that the proposed method is considerably more accurate than existing low-fidelity ones, can provide predictions for both lift and pitching moment coefficients and requires far less computational resources and time when compared to CFD modeling. Hence, it can serve as a valuable aerodynamics and stability analysis tool for BWB UAV configurations.

Highlights

  • Following the research advances in aviation during the 21st century, various technologies have been developed for commercial airliner jets, in an attempt to enhance the aerodynamic efficiency and performance specifications of the well-established, tube-andwing configuration [1]

  • The lift force produced by every airfoil generates a moment in regard to the CG, which is proportional to the longitudinal distance between its point of action and the CG. This component is taken into account using Equation (7), where, xNP and xCG are the longitudinal locations of the neutral point and center of gravity respectively and cmean is the mean aerodynamic chord of the BWB Unmanned Aerial Vehicle (UAV)

  • Dε dα is the downwash slope of the aircraft, calculated with equations found in Reference [10], HCS and Hw are the heights of the aerodynamic center of the control surface section and the mean chord of the wing from the ground, respectively and be f f is the effective wingspan calculated by Equation (15), where bw and b f are taken from empirical/experimental charts found in Reference [10]

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Summary

Introduction

Following the research advances in aviation during the 21st century, various technologies have been developed for commercial airliner jets, in an attempt to enhance the aerodynamic efficiency and performance specifications of the well-established, tube-andwing configuration [1]. Flow control techniques and propulsion architectures are considered for evaluation in terms of aerodynamic efficiency and performance enhancement potential for fixed-wing UAV applications. It can be used to quickly evaluate layout changes and assess their impact on the performance and is fully compliant with the corresponding airworthiness regulations [1,8,12] When it comes to the rapid prediction of aerodynamic and stability coefficients for a BWB UAV, the available literature is considerably more limited and commercial-airliner-oriented. Though, the flow examined in those articles is compressible This in turn allows the use of specific methods and assumptions [24], which are not suitable when a BWB UAV configuration is considered. Additional corrections related to control surfaces deflection and ground effect

Geometric and Flight Conditions Inputs
The Effect of the Control Surfaces Deflection
Ground Effect
Alternative Aerodynamic and Stability Analysis Methods
High-Fidelity Analysis Methodology
Results and Discussion
Control Surfaces Deflection and Trim Diagram Calculation
Conclusions
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