A solar-powered airplane made a smooth trip on Monday from Texas to a stormy part of America – St. Louis, where the Solar Impulse team put a portable, inflatable hangar to its first real-world test.
The third leg of Solar Impulse's "Across America" odyssey may not have been a record-setting trip like last week's flight from Phoenix to Dallas-Fort Worth International Airport. But St. Louis could rank as the plane's most challenging layover to date.
Solar Impulse arrived just days after a powerful storm swept through Lambert St. Louis-International Airport, damaging buildings and strewing the runway with debris. That meant the plane's intended hangar wouldn't be available – but Solar Impulse's team said the flight had to go forward anyway.
"Postponing the flight is not an option, as the particularly difficult weather conditions in the region leave only very few flight possibilities between Dallas-Fort Worth and St. Louis, and it might be the only one this week," the team said in a statement before takeoff. "If Solar Impulse doesn't seize this opportunity, the chances of reaching final destination of the Across America mission as scheduled could be compromised."
So pilot Bertrand Piccard took off at 4:06 a.m. CT Monday, and came in for a landing at 1:28 a.m. Tuesday. That 21-hour-plus flight ranked as Piccard's longest-lasting trip in Solar Impulse's single-seat cockpit. The only trip longer was taken by Andre Borschberg, Solar Impulse's CEO, who holds the duration record with a 26-hour flight in Switzerland in 2010.
After landing, Piccard said the St. Louis stopover was particularly important to him because of the role that the city played in the early days of aviation. The city's business leaders were such strong backers of aviator Charles Lindbergh's historic solo trans-Atlantic flight in 1927 that he named his plane "the Spirit of St. Louis."
“I was so inspired when I met Charles Lindbergh at Cape Canaveral during a launch of the Apollo when I was 11 years old," said Piccard, Solar Impulse's chairman. "I’m truly moved to be able to land here today with Solar Impulse.”
The Swiss-built plane was stowed in an inflatable hangar that's designed to withstand winds up to 62 mph (100 kilometers per hour). Solar Impulse's crew erected the structure at St. Louis' airport over the course of several hours. "The fabric used for this mobile hangar comes from the sailing world," Niels Ryser, head of ground crew operations, said in an explanatory video. "It's waterproof, fireproof, and it's inflated by fans."
The mobile hangar is intended for use during Solar Impulse's round-the-world trip, currently scheduled for 2015. The St. Louis stopover marked the structure's first test in real-world conditions. "This exercise is now a proof of concept: Rather than taking the airplane to a hangar, we have taken the hangar to the airplane,” Borschberg said.
Solar Impulse's two-month-long odyssey from the San Francisco Bay Area to New York is aimed at demonstrating the plane's technology for an American audience – and preparing the way for the more ambitious 2015 tour. The carbon-composite plane has the wingspan of a 747 jet but weighs no more than a passenger car. All of its power comes from the 12,000 solar cells mounted on its fuselage. Electricity is stored in 880 pounds (400 kilograms) of batteries to drive the plane's scooter-sized electric motors through the night.
Borschberg is to fly the plane from St. Louis to Washington in mid-June, and Piccard will take the controls for the final leg from Washington to New York in late June or early July.