Advanced UAV Aerodynamics, Flight Stability and Control

5Unmanned Aircraft Wind Tunnel Testing

R. Bardera Mora

Low‐speed Experimental Aerodynamics Laboratory, National Institute for Aerospace Technology, Madrid, Spain

5.1 Introduction

Many techniques are involved in the design of a new aircraft, but wind tunnel testing is traditionally considered as a key part of the assessment of an aerodynamic design. This chapter describes wind tunnel testing’s role in the development of the Diana aircraft, a new unmanned aerial vehicle (UAV) designed by the National Institute for Aerospace Technology (INTA) in Spain. In a first phase, the airfoils forming the wings and tail were selected in a preliminary design after definition of the configuration requirements. In a subsequent phase, both analytical and computational methods were applied to estimate the aerodynamic characteristics of the aircraft. Aircraft tests were performed in wind tunnels in order to provide experimental aerodynamic insights that would validate the results obtained by the analytical and computational fluid dynamics (CFD) methods that were used in the aerodynamic aircraft design process. Aerodynamic force and moment measurements were carried out by means of a six‐component internal balance. Dimensionless coefficients were calculated directly from raw data in centre‐balance body axes, and were subsequently transferred to wind axes in the usual manner. Finally, characteristic curves of the aerodynamic coefficients were determined and compared with those obtained by CFD methods. ...