Time-Efficient and Accurate Performance Prediction and Analysis Method for Planetary Flight Vehicles Design
The aim of this article is to present a reliable design process of unmanned aerial vehicle to fly in terrestrial and extra-terrestrial atmosphere prepared for a vast spectrum of missions. It is a new methodology, which does not rely on similar designs but investigates the most adequate configuration using already existent tools adapting them for this specific aim. At the end of the process, a multidisciplinary parametric and iterative model is created, that combines the adequate configuration database with semi-empirical methods. The model can also be effectively modified given any changes in the design, manufacturing or flight conditions, which automatically updates the vehicle’s overall performance and design features. The method intends to maximise the use of open source software and numerical codes such as Vortex Lattice Methods with bi-dimensional boundary layer analysis, OpenFOAM CFD analysis, FlightGear with the JSBSim flight dynamics model and Paparazzi autopilot for virtual flight tests, in order to develop tools to analyse the vehicle’s performance such as aerodynamics, flight mechanics, structural integrity and flight strategy. It also incorporates experimental wind tunnel data such as aerofoil polar and semi-empirical methods improving the reliability of numerical analysis. Consequently, a multi-objective model is constructed which interconnects and parameterizes the analysis fields. The parameters of this model can be freely modified and, due to the multi-dependency of all the fields, each modification is propagated throughout the model, updating the global analysis of the vehicle. The method has been applied to predict and analyse the performance of conceptually distinctive configurations, such as box-wing, blended wing body or high-aspect-ratio aircraft. In one case the method avoided flight mechanics instability problems by correctly predicting the vehicle’s behaviour in flight. In another case the multidisciplinary model allowed to successfully adjust the optimal flight conditions for a model whose mass has been altered due to manufacturing inaccuracies. The most representative example of verifying the accuracy and reliably of this methodology is the PRONTAS solar aircraft prototype. PRONTAS is a 16m-span 80kg unmanned solar plane capable of continuous flight at 8000m altitude using only solar energy. The design is focused on civil applications, which include wild fires detection and prevention, wild life migration studies, long-term climate study, search and rescue, satellite alternative etc. The project is lead by the Institute of Technology and Renewable Energy (ITER, Instituto Tecnológico y de Energía Renovables) in collaboration with Aernnova Engineering Solutions and Technical University of Madrid (UPM, Universidad Politécnica de Madrid). The project is financed by The Spanish Government (Ministerio de Economía y Competividad) and The European Regional Development Fund (ERDF). The project served as a teaching platform for aerospace engineers willing to gain experience in the design process of unmanned aerial vehicles with robust practical applications.