Solar Plane Aims for 36-Hour Flight

A prototype of the Solar Impulse, an aircraft powered entirely by the sun, is expected to be unveiled on June 26 at an airfield near Zurich in Switzerland.

One of the plane’s most noteworthy features is a giant wingspan measuring 63 meters (about 207 feet), or roughly that of a large commercial passenger aircraft. That design is aimed in large part at maximizing surface area in order to make it possible to attach 11,628 solar cells.
The plane will carry four 100 kilogram lithium batteries each powering a propeller engine. But the overall weight of the plane is 1,600 kilograms (3,527 pounds), or about that of a car.

The first test flight will be toward the end this year, according to Andr