Hello. A swiss plane has taken off from abu dhabi on the firstever attempt to fly around the world using only the energy of the sun. The Solar Impulse ii could take five months to complete the 12 stages of the flight crisscrossing continents while spreading the word about clean technology. Its a pretty impressive project with some even more impressive figures. Lets show you a two. Two pilots will take it in turns to fly the singleseater plane on the 35,000 kilometer journey. The Solar Impulse ii has a wingspan of 72 meters larger than that of a boeing 747. Built into the wings, more than 17,000 ultraefficient solar cells, which transfer energy to four electrical motors powering the planes propellers. The pilots will have to stay awake for most of their time in the air. They are being allowed naps of just 20 minutes, confined in a cockpit thats not much bigger than a phone box. Mark lobel watched the launch in abu dhabi. Reporter preparing for the ride of their lives. The moment the swi