Solar Impulse 2: 11 Images From Its Awe-Inspiring Journey
If Solar Impulse 2 successfully completes its planned journey through Europe and back to the Middle East, it will have accomplished something previously believed impossible: heavier-than-air flight fueled only by the power gleaned from the sun's rays.
Would you want to fly around the world in an airplane powered only by the sun?
The two pilots handling Solar Impulse 2 have been doing exactly that. The solar-powered airplane set out from Abu Dhabi, in the UAE, on March 9, 2015, and is making its way around the world in a sequence of long hops. It's doing so without using a drop of aviation fuel. Its 236-foot wingspan is covered with solar panels, allowing Solar Impulse 2 to generate all the power its four electric propeller engines need for flight.
After leaving Abu Dhabi, the aircraft faced a nine-month layover in Hawaii. Its batteries needed to be replaced and a new manual cooling system installed and tested. Solar Impulse 2 reached the US mainland April 23, 2016.
(Editor’s note: Solar Impulse 2 took off at 2:30 am ET from JFK on June 20, headed for Seville, Spain. Live streaming of the Atlantic crossing can be found here.)
At press time, the plane was scheduled to depart John F. Kennedy International Airport in New York for its Atlantic crossing on the morning of June 20. If the aircraft successfully continues its planned journey through Europe and back to the Middle East, it will have accomplished something previously believed impossible: heavier-than-air flight fueled only by the power gleaned from the sun's rays.
[Want to learn about Solar Impulse's Silicon Valley stop? Read Solar Impulse Flight Makes Silicon Valley Stopover.]
The aircraft is manned by two Swiss pilots, Bertrand Piccard and Andre Borschberg. Piccard flew the plane from Hawaii to San Francisco, landing the unwieldy aircraft on April 23 at Moffet Field near Mountain View, Calif.
After landing in Mountain View, in the heart of Silicon Valley, the pair visited other US cities: Phoenix; Tulsa, Okla.; Dayton, Ohio; and Lehigh Valley, Pa., northwest of Philadelphia. A planned flight to New York City was cancelled June 7 due to bad weather, and then successfully completed a few days later, on June 11.
Piccard and Borschberg are now positioned to undertake what will be perhaps the most hazardous leg of the journey: a flight across the Atlantic. Although they may try a direct eastward dash to Paris, they are more likely to take the northern route, as Charles Lindbergh did in 1927.
On the northern route, the Solar Impulse 2 can find an emergency airfield along the way by sticking near the New England shoreline and that of the Canadian Maritime provinces. After skirting Nova Scotia and Newfoundland, the aircraft can fly over water and soon reach Greenland, Iceland, the Faroe Islands, and then Ireland. Authorities can be notified and rescue vessels ready along each segment of the route.
Its broad wingspan makes the aircraft vulnerable to storms, which can blow up quickly over the Atlantic any time of year. High winds in the upper atmosphere can blow it off course. A gust of wind that tilts it more than 8.5 degrees is capable of plunging it into a dive from which the pilot may not be able to recover.
Still, Lindbergh made it across the ocean 89 years ago in the Spirit of St. Louis, beating the 10:1 odds Lloyds of London had placed against him making it. Lindbergh's fragile aircraft would now be considered archaic. (His forward view was obstructed by the plane's gas tank.) If the Spirit of St. Louis could make the trip almost a century ago, why isn't Solar Impulse 2 assured of completing the same journey?
With our frequent travel on jetliners, we have forgotten (or prefer not to ponder) how hazardous it can be to fly across an ocean. But, a little more than two weeks before Lindbergh accomplished his crossing, Charles Nungesser and Francois Coli took off from Paris in their custom-built Levasseur PL8, the White Bird, trying to reach New York City before anyone else did. After leaving the coast of France, the big biplane flew out to sea and was never seen again.
Like Lindbergh, Piccard is scheduled to attempt the Atlantic crossing by himself. He has even suggested he may try to land at the same airport as Lindbergh did, Le Bourget, outside Paris.
Unlike Lindbergh, one thing Piccard isn't worried about is running out of fuel. Solar Impulse 2 can generate replacement energy as fast as it uses it. Nevertheless, a life raft is carried in the small cockpit. Just in case.
(All images courtesy of Solar Impulse 2)
Bertrand Piccard, left, and Andre Borschberg, are the two Swiss pilots flying Solar Impulse 2 around the world.
Piccard comes from a long line of adventurers and explorers. His grandfather, Auguste, made the first flight into the stratosphere in a pressurized capsule carried aloft by a balloon. His father, Jacques, established a deep-sea diving record of seven miles below the surface in the bathyscaphe Trieste. In 2003, Piccard launched the Solar Impulse project.
Borschberg is a former Swiss Air Force fighter pilot and engineer. He flew the helicopter from which pictures were taken of Solar Impulse reaching San Francisco after traveling from Hawaii.
The infographic above shows the possible routes pilot Bertrand Piccard could end up taking over the Atlantic, including one that allows the Solar Impulse 2 to land outside Paris at Le Bourget Airport, the final stop for Lindbergh's Spirit of St. Louis nearly a century ago. Choices will depend on the weather conditions en route. A mission control center in Monaco continually monitors the position of the plane and the vital signs of the pilot. A meteorologist is on hand at all times to advise the pilot.
Solar Impulse 2 is capable of flying through the night (shown here in Switzerland). It's an eerie sight, with its 16 LED lights blazing as it takes off or comes in for a landing. It is able to generate excess power during the day, which it stores in four custom lithium-polymer batteries onboard. It also climbs to a height of 28,000 feet by sundown, allowing it to fly on reduced power as it slowly drops in altitude through the night to 8,000 feet. When the sun rises, if all goes well, it still has 10% of its battery power left.
Two crewmen stow one of the lithium-polymer batteries powering Solar Impulse 2 through the night in its insulated compartment. The batteries have an improved oxidizing process invented by Kokam, a South Korean battery company, to maximize their energy-carrying capacity. The four lithium-polymer batteries weigh approximately 1,408 pounds, accounting for a significant portion of the aircraft's total 5,100 pounds of weight.
Solar Impulse 2 generates electricity with an upper wing surface composed of 17,248 solar cells manufactured by SunPower in San Jose, Calif. The cells are part of a thin carbon-sheet skin covering the wings. The frame is made of a lightweight composite material similar to that used to build racing yachts. The technicians pictured above are working near the joint where the outer wing angles slightly upward. In aircraft design, that angle is known as dihedral. It contributes to the stability of the plane. Part of each wing's lift pushes toward a center point above the plane, resisting sudden changes.
The four engines driving the propellers on the Solar Impulse 2 are not standard aircraft engines in any way. They are motors produced by Schindler Elevator Corp. and normally used to run elevators. The motors were given a custom nacelle, or casing, for the Solar Impulse 2. Even with all four at work, however, the cruising speed of Solar Impulse 2 is about half that of a car on the Interstate -- 35 mph to 40 mph. On the other hand, according to pilot Bertrand Piccard, a standard jet engine wastes 70% of the energy in its gasoline fuel as surplus heat. The motors on Solar Impulse 2 convert 97% of the electricity provided to them into propeller propulsion.
Solar Impulse 2 is shown at about 3,000 feet above San Francisco's Golden Gate Bridge as pilot Bertrand Piccard arrives in San Francisco from Hawaii April 23. He descended to fly alongside the bridge, then circled over the bay, and at sundown landed at Moffett Field near Mountain View, Calif.
Piccard shared some hair-raising stories during an interview with InformationWeek. He spoke with us while he was in San Jose April 28 visiting employees of ABB, which manufactures relays and instruments used in solar systems.
Piccard told us how he learned, unexpectedly, the aircraft would actually tolerate an 8.5-degree bank. The flight manual states safe flying constitutes banking 5 degrees or less, and the pilot receives a warning vibration on his sleeve if he reaches that point. Piccard said was trying to take a nap during the 2.5-day journey from Hawaii to the Bay Area when mission control alerted him that the plane had banked past 5 degrees. Awakened from his sleep, Piccard said in the time he needed to get his pilot's seat out of its reclining position, the plane's bank had reached 8.5 degrees. The previous tolerance was considered 8 degrees.
Another story Bertrand Piccard shared in his interview with InformationWeek involved the aircraft's batteries.
According to Piccard, pilot Andre Borschberg was reaching the final stage of his long flight from Japan to Hawaii when he calculated he had plenty of energy left in the batteries to reach the islands with the current that was still in reserve. He had been aloft for nearly five days and was ready to get to his goal. So he sped up, increasing the amperage at which power was withdrawn from the batteries. The batteries occupy well-insulated compartments so their function won't decrease at the cold temperatures encountered at high altitude, which typically average -22 Fahrenheit (-30 Celsius).
"Because the battery insulation is so good, it trapped the heat, the batteries overheated. They were damaged … It was a human error," Piccard told InformationWeek. Borschberg made it to Hawaii, but flight teams spent the next nine months replacing the batteries and retesting the aircraft.
The insulation used on the battery compartments is also used on the cockpit, protecting the pilot from some of the extreme temperatures outside the aircraft. Still, Piccard said, it is wise for the pilot to wear good ski clothing for the higher-altitude parts of the flight.
The reclining pilot's seat is visible in this picture of the cockpit, with all its instrumentation. Behind the pilot's headrest is a set of green oxygen bottles. The cockpit is unpressurized as well as unheated, meaning the pilot is dependent on oxygen masks after reaching an altitude above 12,000 to 14,000 feet. For those who need to know, the pilot's seat converts into a potty chair and back again, when the call of nature requires it. Otherwise, there is little room to move around in the cramped cockpit.
Since their departure from the Middle East, pilots Bertrand Piccard and Andre Borschberg have been attempting to spread a message: A cleaner energy future is close at hand, and we can liberate ourselves from dependence on carbon-based fuels. Nowhere did they wish to carry that message from more than New York City, with its iconic Statue of Liberty.
With Borschberg at the controls, the Solar Impulse staged its own fly-past as the mission's way of advocating a carbon- and pollution-free future for all.
If Piccard and Solar Impulse 2 reach Europe without mishap -- possible touchdown spots include Ireland, Great Britain, France, Portugal, and Spain -- the project will have to complete only two more relatively short hops. Then it will have reached Abu Dhabi in the UAE, the mission's point of embarkation. When it gets there, it will have completed a trip of 21,748 miles (35,000 kilometers).
If Piccard and Solar Impulse 2 reach Europe without mishap -- possible touchdown spots include Ireland, Great Britain, France, Portugal, and Spain -- the project will have to complete only two more relatively short hops. Then it will have reached Abu Dhabi in the UAE, the mission's point of embarkation. When it gets there, it will have completed a trip of 21,748 miles (35,000 kilometers).
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