By Matthew L. Wald | The New York Times
CHANTILLY, Va. — Nearing the end of a cross-continent flight powered by solar electricity, the designers of the Solar Impulse airplane are looking at the challenge of flying around the globe but focusing on the weak spot in their cutting-edge technological effort: human frailty.
Solar Impulse stands out among airplanes partly because its range is limited not by fuel but the stamina of the pilot.
The single-seat airplane’s cabin is unpressurized, so the pilot must wear an oxygen mask. It has no bathroom. With a grand total of 40 horsepower, the average cruising speed is 38 knots, or about 44 miles an hour, so progress is slow. Even if a pilot can tolerate 26 hours in the tiny cockpit — the record so far — an oceanic flight is hard to imagine.
“The seat is like a really bad economy seat on an airliner,” said Gregory Blatt, a managing director of the company, which is based in Lausanne, Switzerland. “The next version will be like a good business-class seat.”
That version, which is supposed to be able to fly five or six days at a time, will have a bigger seat, a cabin large enough to move around in, some plumbing and various other upgrades, like an autopilot. But that means a heavier plane that will require more efficient solar cells, electric motors and other improvements.
A Solar Impulse plane, an eye-catching proof-of-concept vehicle, arrived at the Smithsonian Air & Space Museum’s branch at Dulles Airport over the weekend from St. Louis, part of a photovoltaic barnstorming tour. The plane’s designers say the successor airplane, already under development, needs crucial but incremental improvements.
