Sunny-side up for this airplane

The sun proved to be the undoing of an early flyboy named Icarus, but it could prove to be very uplifting for a 21st-century aircraft.

At the Paris Air Show this week, a team of engineers, marketers and prospective pilots showed off a scale model of an ambitious solar-powered vehicle--which in its present state looks like an upscale balsa wood airplane. The goal of the Solar Impulse project is to build a full-size version of the aircraft and fly it around the world.

The airplane will have a very lanky wingspan of 80 meters, or nearly that of the much bulkier new Airbus A380 superjumbo jet, and will weigh in at an "ultralight" 2 tons, backers say. It'll carry just a single occupant, compared with as many as 800 passengers for the A380. Much of the weight will come from batteries that will store the solar energy accumulated during daylight hours via 250 square meters of solar panels atop the wings, according to a report from the air show. In the current design, two engines will provide 40 horsepower of thrust, but the aircraft will also glide at night, dropping from 10,000 meters to 3,000 meters.

If all goes well, the Solar Impulse craft would make its first flight in 2008, and its circumnavigation of the globe is penciled in for 2010. So far, a team of 60 specialists has been at work on the project for 15 months. The budget weighs in at a not so ultralight 40 million euros ($48 million), about a quarter of which has already been allocated.

A key figure in the project is Bertrand Piccard, its founder and president, who'll also be one of the aircraft's pilots. The Swiss psychiatrist and adventurer was captain of the first nonstop, round-the-world balloon flight in 1999.

The Solar Impulse team also used the air show to give a nod to its partners, which include Solvay, a Belgian plastics company that is providing "decisive R&D resources;" the Swiss Federal Institute of Technology at Lausanne; engineering group Altran; Daussault Aviation; and the European Space Agency.