Solar plane to start world tour this weekend
太阳能飞机本周将开始环球飞行

The world's biggest solar-powered plane is to start a round-the-world tour this weekend to promote alternative energy.

The Solar Impulse 2 completed a third successful test flight in the United Arab Emirates on Monday. Organizers hope it will start its world tour as early as Saturday... but have cautioned the launch depends on weather, even in the relatively cloudless Gulf. After taking off from the capital Abu Dhabi, the plane will travel to 12 cities during a five-month tour. The project is the fruit of 13 years of research and testing by two Swiss pilots. The plane is powered by more than 17-thousand solar cells in its wings. The wings are 72 meters long, almost as long as those of an Airbus A-380.