The project that hopes to ultimately send a manned aircraft around the world in nonstop flight utilizing solar power has reached the concrete phase through delivery of final first aircraft components. The first large components now exist for the yet unbuilt aircraft registered HB-SIA, and composite fuselage has run through stress tests including static flexion and torsion testing. Normal challenges of aircraft design — ultra-light, ultra-robust construction — are compounded in the Solar Impulse project and its more than 180-foot-long wing. “Anything that doesn’t break is potentially too heavy,” says project CEO Andre Borschberg. Anything too light obviously offers similarly project-ending consequences. The extreme combination of experimentation and computer simulation has so far stretched carbon sheet “just a few tenths of millimeters thick over lengths up to 20 meters” and challenged researchers to transform fragile solar panels into flexible wing surfaces.
HB-SIA will be the project’s first prototype aircraft and it will offer a 61-meter solar-panel-coated wingspan. Its mission is to prove its construction technology and hopes remain that it could make a 36-hour flight in 2009 without the use of any fuel. Fifty specialists from six countries and roughly 100 outside advisers are providing brainpower for the project.
