When the sun-powered Solar Impulse aircraft takes off next month from California on its mission “Across America,” the breakthrough airplane will fly with more than 6,000 parts made from 11 different Solvay products including high-strength, lightweight plastics, battery components, lubricants, insulation and solar panel film coatings.
Solar Impulse is the world’s first solar-powered airplane capable of flying day and night without fossil fuel. Special materials and expertise from Solvay, a global producer of chemicals and advanced materials, optimize the aircraft’s energy chain and contribute to the plane’s remarkably light, yet sturdy, structure.
Solvay is a founding partner of the Solar Impulse consortium that also includes companies with expertise in solar technologies, aviation, engineering, electronics, mechanics and controls.
Solar Impulse’s long wingspan (comparable to a 747 airliner) accommodates more than 10,000 solar panels that cover the wings’ surface. These photovoltaic cells capture the solar energy that turns its propellers, allowing the aircraft to fly. Solvay’s PVDF (Solef®) and ECTFE (Halar®) polymers are used for ultra-thin single layer films, laminated films, and adhesives that “encapsulate” the cells to reduce the impact of stressors, deformations, temperature variations and solar radiation that occur when flying.
Energy captured from the photovoltaic system is stored for night flight in high-efficiency lithium batteries, which contain PVDF (Solef® ) and Solvay’s electrolyte component monofluoroethylene carbonate (FIEC®).
Solvay materials also play an important role in reducing the overall weight of the aircraft. All parts that would traditionally be made of metal, including the instrument panels and control box, are instead made of ultra-light but resilient polymers.
These materials, such as Solvay’s polyphenylsulfone (Radel®) and Polyamideimide (Torlon®), have densities between 1.4 and 1.8 ρ (kg/m3). By comparison, metals like aluminum, iron and titanium have far greater densities ranging from 2.7 to 7.9 ρ (kg/m3).
Further weight reduction is achieved by using hundreds of plastic screw-nut-washer systems made with Solvay’s self-reinforcing polyphenylene (Primospire®) — one of the stiffest and strongest unreinforced plastics in the world — rather than typical metal nuts and bolts. The result is a plane with a wing span of a jumbo jet, the total weight of a compact car, and the power of a scooter.
Other Solvay technologies aboard Solar Impulse include polyurethane foaming agent (Solkane 365mtc®) for heat insulation and perfluoroether (Fomblim®) for lubrication. Keeping the plane’s rotating parts well-lubricated aids the aircraft’s energy efficiency.
“Solvay has sponsored this project since its inception in 2004 because we are deeply committed to sustainability principles and we wanted to challenge ourselves in this domain,” explained George Corbin, head of research, development and technology at Solvay Specialty Polymers. “Even though we are a partner on the project, Solar Impulse can source materials from any company, including our competitors,” he added. “So we worked hard to develop superior material solutions and are proud to have many of our unique products aboard Solar Impulse.”
The Solar Impulse “Across America” mission begins on or about May 1, weather permitting. It will fly across the U.S. and stop for extended visits at several cities including Washington, D.C. in June and New York in July.
This week, Solvay’s Research and Innovation, Chemicals, Specialty Polymers and Rare Earths groups hosted Solvay customers, Silicon Valley entrepreneurs and technology startups for a close-up look at Solar Impulse, at Moffett Field of NASA’s Ames Research Center, here. Solvay and Solar Impulse will host other events at each destination, including a special event at the Smithsonian National Air and Space Museum annex at The Steven F. Udvar-Hazy Center at Dulles International Airport near Washington, D.C.