FTERO student team testing the LARAII prototype (17 May 2017)
FTERO student team preparing the first flight of the CLARA prototype (16 May 2017)
FTERO student team with CLARA prototype (5 May 2017)
Lorenz Affentranger BSc Student ftero ś ETH Zürich
Laboratory of Composite Materials and Adaptive Structures Tannenstrasse 3 8092 Zurich Switzerland alorenz@ethz.ch www.ftero.ch www.facebook.com/fteropower
ftero ś On the Development of an Airborne Wind Energy System
Lorenz Affentranger, Leo Baumann, Renato Canonica, Ivan Gehri, Gabriel König, Cla Mattia, Andreas Michalski, Fabian Wiesemüller, Oliver Wild, Urban Fasel, Dominic Keidel, Giulio Molinari, Paolo Ermanni
ETH Zurich
The ever-growing consciousness towards the indepen-dence from fossil fuels, and the awareness of the pro-found effects of non-renewable energies on the climate, has motivated researchers around the world to search for innovative renewable alternatives for energy production. Airborne wind energy (AWE) is a very promising candidate for this problem. The ftero project, represented by ten BSc students in their final year, aims to push the bound-aries of current AWE systems by building a demonstra-tor featuring innovative concepts capable of radically im-proving the reliability and performance of the technolo-gies current state.
The core focus of the ftero project is to develop a fully functional AWE system, primarily focusing on the aero-dynamic, structural and control aspects of the aircraft. The developed system consists of a mobile ground sta-tion, developed for the vertical take-off and landing, the aero-structurally optimised aircraft, and an efficient controller for the take-off, landing, traction, and reel-in phase. Throughout the project, multiple prototypes were built in order to test and evaluate the aerodynamic and structural characteristics as well as the control strategies of the aircraft. Utilizing the know-how obtained by these prototypes, the final aircraft comprises of a high aspect ratio, high-lift wing with 5m span, two fuselages and two tether attachment points. In particular, the outer shape of the wing and its internal load-carrying structure have been concurrently optimized to maximize the power
pro-duction while maintaining the structural efficiency ś and hence the mass ś to a minimum. Two electric motors, each mounted on the fuselage enable zero-length take-off and landing with the airplane in a vertical nose-up at-titude. The advantage of this vertical take-off and landing system are the possibility to perform very space-efficient autonomous start and landing manoeuvres. In the rear-most section of the fuselages, the fully moving horizontal tail enables large control moments, necessary not only during the traction phase, but also during the take-off and landing manoeuvers. For testing purposes, a ground station was adapted to handle loads up to 10kN, and to produce a maximum power of 40 kW.
The possibility of designing and optimizing synergically all the various components of the AWE system enables the demonstration of the technical feasibility and the ac-tual performance of every aspect of the technology, while dually permitting to introduce innovation and optimisa-tion in every scientific discipline involved. The system will further allow to test future aerodynamic, structural, and controls concepts on a physical system. To this end, sev-eral scientific studies on structural optimisation and con-trol theory are conducted in cooperation with ftero, in-cluding an ongoing study aiming to extend the functional-ity, operational envelope and performance of the aircraft by means of compliant morphing wings.
