Pipistrel taurus G4: On creation and evolution of the winning aeroplane of NASA green flight challenge 2011

The paper presents the journey of the Pipistrel's Taurus G4, the World's first four-seat electric aeroplane and winner of the NASA Green Flight Challenge 2011, sponsored by Google, from idea to completion of competition. At the beginning, the race event and qualification requirements are presented. The selection of the aeroplane's configuration and sizing is discussed, and emphasis given to the unique twin-fuselage configuration. Next, the architecture of the electrical systems on board the aeroplane, including the large battery pack and propulsion elements is presented. In the second part of the paper, authors give an insight to the 40-hour flight test, the challenges encountered and the preparation to the race event itself. A non-linear mathematical performance model was developed to predict performance of the Taurus G4 during the two race events and used for flight planning and in-flight online performance optimisation. Instead of the conclusion, the results of the NASA Green Flight Challenge 2011 are presented and discussed, together with a comparison to other participating teams' results.