DESIGN AND TEST OF A UAV BLENDED WING BODY CONFIGURATION Kai Lehmkuehler * , KC Wong * and Dries Verstraete * * School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Australia kai.lehmkuehler@sydney.edu.au Keywords: Blended Wing Body, UAV, Wind tunnel, Stability, Propulsion Effects Abstract This paper presents the design and test of a UAV blended wing body configuration. It is the re- sult of a global student design project between the University of Sydney, the University of Col- orado and the University of Stuttgart. Firstly, the design methodology and constraints are in- troduced. Then the wind tunnel test setup is de- scribed and the data presented. Finally, an engi- neering method to predict the propulsion effects on this unusual airframe is described. Comparison between the wind tunnel data and panel code predictions shows good agree- ment, also reinforced by successful flight tests. Propulsion effects on a low stability airframe can be serious and need to be considered during the design to avoid possible instabilities. The method presented allows for a quick estimate without tedious computations or tests. 1 Introduction Blended wing body (BWB) configurations have attracted considerable interest lately as an alter- native, more efficient platform for transport air- craft [1][2]. In conventional tube-wing config- urations the fuselage typically contributes only minor amounts of lift while adding considerable skin friction drag as well as a disruption of the lift distribution across the wing. BWBs locate their payload volume inside the wing such that the entire external surface contributes to the gen- eration of lift and the aircraft can be shaped for an optimal lift distribution. Typically they also are tailless flying wings which potentially further reduces the drag. The use of BWBs for full scale transport air- craft is still some time away due to several prob- lems; mainly the compliance with current reg- ulations is difficult if not impossible (passenger evacuation, aircraft control without artificial sta- bility and so on). Another application for a BWB might be a smaller, unmanned platform, where most of these constraints do not apply but high efficiency and large internal volume are required. Therefore the aim of this project is to design and test a small scale BWB and to determine if the platform is a viable configuration as a UAV. The aircraft discussed in this paper is the first iteration of the project. It was designed for the international Hyperion project, which was a co- operation of student teams from Sydney, Aus- tralia, Stuttgart, Germany and Colorado, USA. The Sydney team was tasked with the airframe conceptual design and the wind tunnel testing. The plane was built in Germany and the US, where it was flown successfully in April 2011. This paper will outline the design and testing conducted before the first flight. Future publica- tions will cover the flight testing and the continu- ing development of the platform. 1