If you have sat in the window seat, chances are you noticed that the airplane window was made of plastic. In fact, most aircraft include plastics in their design and have done so from the early years of human flight, yet the technological history of synthetic polymers in aviation is largely unexplored. This may be because the materials we call “plastic” are conjured up behind the curtain of a chemistry laboratory. It is mysterious stuff that we do not understand like metals, wood, and other materials with which we have longer experience. It makes sense that early plastics were rather experimental, and we now are seeing that some hold up better than others over time. With generous support from NCPTT, the Smithsonian’s National Air & Space Museum and Museum Conservation Institute have teamed up to characterize and assess the history and stability of early 20th-century aviation plastics, beginning with a novel, non-invasive study of goggles, helmets, and airplane windows.
In 1903, the Wright brothers made their first powered flight at Kitty Hawk in an open architecture aircraft. By 1910, pilots were given some protection from the slipstream and elements by covering the aircraft’s skeletal frame with fabric and leaving an opening on top for the pilot’s head and shoulders. These early cockpits, as they would become known, were located behind the engine, and the pilot was pelted with wind, rain, ice, engine oil, and the occasional, unfortunate bird that happened into the propeller. All threatened the pilot’s ability to see and maneuver the plane. Goggles and small windshields were a first line of defense, provided they did not fail. As flying became more common, ambitious pilots were expected to fly ever higher and faster and year round. This brought the need to enclose aircraft while at the same time see out of them. Reliance on eyewear as a first line of protection gave way to protection of the entire cockpit. This period of aviation happened to coincide with the development of water-clear transparent plastic sheets that were lighter than glass, more flexible, easier to shape, and less likely to shatter on impact. Aviation soon became a target market for these plastics and a test bed for new materials that would have far reaching implications for other industries as well.
Where else but the Smithsonian could you find a complete timeline of airplanes and headgear to study? This project leverages the world’s largest air and space collection as evidence of the materials and technologies used to create plastic window in the early-20th century. The survey will rely heavily on Raman spectroscopy, an analytical technique that is ideal for identifying polymers and 3-dimensional plastic materials. Recent innovations in photonics have made possible portable Raman spectrometers that weigh only a few pounds. This is a boon for air and space collections, where most artifacts are too large to be brought to the laboratory. The Smithsonian study will improve our ability to identify plastic compositions, which is a key step in preserving both this history and the artifacts with which we are entrusted.
For more information on this project, see the final report.