After 2 years of intense “construction works”, the most significant part of the Solar Impulse’s prototype has been delivered to the hangar last week: the main spar for the first airplane’s 61meter-wing. After a long journey of 200km departing from the Décision naval dockyards situated close to the Lake of Geneva the spars have safely arrived to Dübendorf in three huge 20m “box” beams. After assembly, in the following weeks, the 61meter-wing will undergo vibration tests together with the wing’s subsystems (landing gear, flaps and spoilers) in explore the aircraft’s aero-elasticity and avoid the so called buffeting (an oscillation produced by air flows). Once tested, these elements will be integrated one by one, giving shape to the prototype – as André Borschberg puts it: “I’m still having a hard time realizing that it’s with this that we’re going to be able to fly.”