Earlier this month, we described the successful flight of Solar Impulse, a manned solar plane that flew for over 26 hours before a safe landing in Switzerland. Now comes news of another feat of solar-powered derring-do. Currently circling above Arizona, a British-built unmanned solar plane dubbed the Zephyr has now flown for a record-breaking seven days straight. Zephyr's developer, the defense company QinetiQ, hopes the plane can stay aloft and double its own record for a total of fourteen days. With a 74-foot wingspan, this latest version of the Zephyr is fifty percent bigger than its predecessors. Its designers hope that the plane will one day find use both for military reconnaissance and also for scientific research. Without a payload, it weights about 110 pounds. Says project manager Jon Saltmarsh:
"Zephyr is basically the first 'eternal aircraft.'... The launch was absolutely beautiful; it was just so smooth," said Mr Saltmarsh. ...
