Flying by the Sun
Solar-powered aviation is light years ahead of where it was just 10 years ago, but still has a long way to go before it threatens traditional combustion engines
AS A CHILD, BERTRAND PICCARD MET CHARLES
Lindbergh and saw the airships, balloons and steam ships that had crossed the Atlantic, firing his imagination. Half a century later, in July 2016, his dream came true when he climbed out of Solar Impulse 2 in Spain, having left the U.S. three days earlier on an epic aviation journey that was powered only by the sun. It also completed a 16-stage circumnavigation of the globe that he and his Swiss compatriot Andre Borschberg started last year.
The trip wasn’t without hiccups. It was interrupted when the aircraft’s night-flying rechargeable batteries suffered thermal damage. But the Solar Impulse 2 is an impressive feat in engineering. The plane’s super-strength carbon-fiber wings have a span as wide as a jumbo jet, yet it weighs the same as a car and travels at automobile speed. Its ultra-lightweight frame means it struggled against the Atlantic’s fast-changing winds to stay at the altitudes needed to harvest the sun’s power. Having traded space for weight, the two men shared a coffin-sized cockpit, taking turns flying the single-seater.
Their 2009 prototype, Solar Impulse 1, was designed to remain airborne for only 36 hours, showing how far solar aviation has travelled in recent years. Yet it has a long, long way to go before it catches the jet fuel-propelled engines that transport millions of passengers every day. To put their achievement into historical context, the Wright brothers flew into history in 1903. Eleven years later pilots fired machine guns at each other over France and in 1927, Lindbergh crossed the Atlantic.