Solar Impulse Crossing the Continent on Sunshine
Solar Impulse, the company behind the first aircraft that can fly day and night with only solar energy, has set a team out on a journey to cross the American continent. Piloting the HB-SIA prototype are Solar Impulse co-founders Bertrand Piccard and Andre Borschberg. Each segment of the journey is being streamed live on Solar Impulses’ website as well as Twitter and Facebook. When watching the stream, viewers will be shown telemetry including altitude and speed information in real time.
The first leg of the journey was completed on May 3rd, 2013, with Piccard flying the aircraft from San Francisco, CA to the Pheonix area. Today the plane is on it’s second leg, journeying from Phoenix to the Dallas/Fort Worth area. Future legs will take the team to St. Louis, Washington DC, and finally to New York.
The HB-SIA is a technical marvel with a huge wingspan, equal to that of an Airbus A340, and proportionally tiny weight — that of an average car. Every aspect of the aircraft, it’s carbon fiber structure, propulsion chain, and flight instrumentation has been designed to save energy and weight while resisting hostile conditions that will face the pilot and plane at high altitude. With a top speed of just 43 miles per hour, Solar Impulse is not targeting any speed records any time soon. The records of distance and flight time, however, have been re-written by Borscheberg and Piccard’s team. In 2010 Solar Impulse flew the plane for a record 26 consecutive hours, ascending to an altitude of nearly 28,000 feet. When the plane landed, about an hour before dawn, there was enough power remaining in the craft’s lithium polymer batteries to fly for an additional 6 hours.
The aircraft’s structure, propellers, fuselage, and wing are predominately composite materials. The single wing is composed of carbon ribs and a carbon fibre and honeycomb sandwich, all covered with 12.5cm square solar cells. Aerodynamically profiled, the wing has 10,748 cells on it’s upper surface, totaling 200 square meters of solar energy capturing surface. The fuselage is composed of four longitudinal carbon fibre tubes, linked by smaller, diagonal secondary tubes, creating a very light yet rigid structure.
In addition to serving as a proof of technology, Piccard hopes the public will see their accomplishments as motivation. “We want to motivate people to be pioneers,” said Piccard. “We want to show solutions. To show hopes. We want to show what is possible. People talk about protecting the environment and it’s boring,” the 53-year-old Swiss aviator/psychiatrist said. Discussions about climate change are even worse. “Those,” he added, “are boring and depressing.”