Five days, 4,000 miles, no fuel
Next week, pilot André Borschberg will take off in the solar-powered plane Solar Impulse 2. After he does, he’ll be in the air for five days, traversing the Pacific Ocean on his way from Nanjing, China, to Honolulu, Hawaii alone. It only gets crazier from there.
This hop from China to Hawaii is just one leg in a much longer 12-jump trip that’s taking the solar-powered plane and its two pilots around the globe. Shortly after Solar Impulse 2 touches down in Hawaii, its other pilot, Bertrand Piccard, will be taking it back up and across the rest of the Pacific on a four-day flight to Phoenix, Arizona.
Each leg has been a challenge, but these oversea flights are especially grueling. The pair have been preparing for them for years.
THE STAKES ARE HIGH; THERE’S NO BACKUP POWER SHOULD BANKED SUNLIGHT-ENERGY RUN OUT TOO EARLY
Five days is a long time—a commercial jet could make the same trek in some 12 hours—and it takes so long because the Solar Impulse 2 is slow. Its cruising speed is around 25 to 30 knots (roughly 30 miles per hour), Piccard tells The Verge. That is positively pokey, an order of magnitude slower than your average jet.
The tortoise speed is because its 17.4-horsepower motors and four propellers are powered only by the light of the sun hitting the panels on its 208-foot wings, which offers precious little energy compared to jet fuel. So little, in fact, that to make it through the nights, the Solar Impulse 2 has to climb up to roughly 28,000 feet in the morning, coasting down to as just a few thousand at night in order to save precious power.
That up-and-down path comes with a host of complications all its own. For one, at the upper the peaks of the oscillating path, the atmosphere is perilously thin. And because the Impulse 2 doesn’t have a pressurized cabin (left out for weight considerations), it’s all oxygen masks and shivers up there. Plus, pilots enjoy the perk of never sleeping more than 20 minutes at a time. The Impulse 2 is an amazing but fickle machine, and she needs a pilot’s attention at least three times every hour just to keep things on track. After all, the stakes are high; there’s no backup power should banked sunlight energy run out too early. Borschberg will have a parachute and a dry suit, but as Wiredpoints out, there’s still the danger of electrocution, and the unpleasantness of two or three days on a life raft to contend with.
To prepare for their four- and five-day trips, Piccard and Borshberg have both spent long stints in a a cramped simulator. That’s on top of the handful of 10-15 hour flights they’ve logged on the journey’s first half-dozen legs. But spending days seated with barely enough room to stretch is one thing when you’re in a hangar somewhere, and another when you’re above the ocean.
For now, takeoff for the next leg is scheduled for sometime around or after May 11, 4:00 PM ET. It’s subject to change however, due to the very very specific weather required: The Impulse 2 needs sunlight for the first three days at least. With no options for an emergency landing, two out of three is bad. In addition, the Impulse 2, slow and light as it is, does not take kindly to wind. At times, headwinds have lead the plane to wind up flying backwards. So planning a flight of this length is ridiculously hard.
But if all goes as planned, two of the most grueling legs in the journey will soon be over, and the Impulse 2 will be that much closer to accomplishing its wildly ambitious goal of fuel-free circumnavigation. More solar power to ’em.
Source: Solar Impulse, Wired, The Verge
"tkmechaero" 