Our Solar Impulse engineers gave some incredibly good news last week when they announced that Decision, our key supplier of large carbon parts, completed the second airplane’s new wing spar.

In July 2012, during the final structural test of the wing spar, the central part succumbed to the load and broke. This was a vivid reminder that pushing the limits is no easy task and that sometimes, when you’re right on that thin border, you may fall overboard. However, what might have been dramatic in July last year has become an advantage today; the construction delay of HB-SIB brought many new and exciting opportunities such as this year’s Across America mission.

The wing spar is pretty much the solar airplane’s backbone and most important part. It’s the central structure of the wings and, in Solar Impulse’s second generation airplane, it is much larger for a plane meant to fly faster. Consequently, the wings will be subject to more loads by a factor of two. During last year’s failure only the central part of the spar broke and, after thorough testing, the two outer sections of the spar were spared. Nevertheless, the entire spar was rebuilt for consistency reasons, a process that took 10 months, as the design and the production process have since improved. The leftover outboard sections will be kept as a backup.

The wing spar looks like a long rectangular box. It’s fully made out of carbon and it’s glued – or bonded, as the engineers say - together via a very special chemical process, including 20 curing cycles, in a gigantic oven. It takes 64 minutes to bond the parts together and 88 minutes total for the final bracing and cleaning. These time limits must be strictly respected to avoid an uneven process, which can be fatal for the structural integrity of the entire wing spar.

Everything went according to plan thanks to positive collaboration between Decision and our engineers, both working hard to achieve the best and most precise results.  

For more information about the construction of HB-SIB, check out the Making Of or HB-SIB timeline. 

The first event week in Phoenix proved the high interest of the public in Solar Impulse - certainly beyond what was expected. The demand was so high that we had to open an extra public day, in addition to the two originally scheduled.  There were people of all ages, families with kids, aviation enthusiasts and renewable energies supporters. A total of 2,250 people had a chance to view the airplane and we’re hoping to share the same excitement with many more in the stopover cities along the way.

In the evening, the Swiss Consulate organized a dinner event under the wings of the solar airplane with the presence of numerous Consuls, an Ambassador and two Judges including the Governor of Arizona, Mrs. Jan Brewer, the Honorary Consul of Switzerland, Alisa Jost, Secretary of the State of Arizona, Ken Bennett and the Chairman of the Consular Corps of Arizona, Michael Chan.

The mood was festive to the beat of Frank Sinatra’s “New York, New York” – Big Apple here we come! During the event, Bertrand renamed Governor Brewer “Solar Queen” because of the significant investments in solar power Arizona is making with the ambitious objective of making Arizona the first clean tech State in the United States.

Beyond Across America and the mission’s final destination, there were talks about the flight around the world, scheduled for 2015. The Consul General of Mexico, Victor Trevino Escudero, said he hopes his country will extend the partnership to Solar Impulse for a 2015 stopover in Mexico, but I’m afraid he might have some competition for this privilege with a much younger visitor... At the end of a public visit, a little boy carried in his mother’s arms cried out: “Mom, is that going to be the last time I get to see the plane?” We might want to consider paying another visit to Phoenix in 2015 as well, before going to Mexico, as it might make many kids, and this one in particular, very happy.

Photo left: Bertrand, Governor of Arizona, Jan Brewer and André. 

Last week, the Solar Impulse team at Moffett was presented with an unusual visit. Sir Richard Branson, Founder and Chairman of Virgin Group, British business tycoon and entrepreneur, showed up at Moffett Airfield. Although it might have appeared as a surprise, the parallels between Solar Impulse and Richard are all too evident for it to be a simple coincidence.

Richard and Bertrand have a relationship that stretches back to their ballooning days. In fact, Richard, with Per Lindstrand, were the first to cross the Pacific Ocean in a hot air balloon in 1991. Seven years later, in 1999, Bertrand, with Brian Jones, were the first to circumnavigate the globe beating Richard, Linstrand and Fossett’s similar attempt in 1998. “I doff my cap to him” Richard said elegantly when asked about the potential rivalry this might have caused.

Richard was extremely enthusiastic and impressed at the sight of Solar Impulse, to the point that he jokingly added, "I just need to find a way to smuggle that plane out in my pocket!” Richard is also looking at ways to harness solar power by using it to tow aircraft onto the runway in the near future.

One could feel the camaraderie between André, Bertrand and Richard as the pilots showed off their engineering jewel to the Englishman. He even recognized, in HB-SIA’s sleek silhouette, a great communication tool – a message carrier, a “weapon” to showcase the potential of clean techs and innovation – values Richard also shares.

Richard didn’t hesitate to become Solar Impulse’s Patron and, as he was leaving for another engagement in his busy schedule, he gave big thumbs up with his trademark smile “I always set myself challenges that might seem impossible…” Wait, haven’t I heard that somewhere already? André? Bertrand? I think we found our project’s new soul mate!