This presentation is part of Preserving U.S. Military Heritage: WWII to the Cold War, Fredericksburg, Texas, June 4-6, 2019.
by Odile Madden
Early aviation design incorporated the most innovative plastics of the time, and examples of these technologies are represented in the Smithsonian National Air and Space Museum (NASM) collection. Particularly interesting is the co-evolution of transparent sheet plastics and the enclosure of cockpits in heavier-than-air aircraft of the 1920s through World War II. A novel, non-invasive study of goggles, helmets, and airplane canopies in Smithsonian collections was the first known large-scale technical survey of aviation plastics. It leveraged the world’s largest air and space collection as evidence of the materials and technologies used to create polymeric windows in the early-20th century.
The Wright brothers first flew at Kitty Hawk in an open architecture aircraft. By 1910, aircraft were streamlined and pilots were given some protection from the slipstream and elements by covering the aircraft’s skeletal frame with fabric, leaving the top open for the pilot’s head and shoulders. These early cockpits were located behind the engine, and the pilot was pelted with wind, rain, ice, oil, and the occasional 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 defense, provided they did not fail. As flying became more common, ambitious pilots flew ever higher, faster, and year round, which brought the need to enclose cockpits and still see out of them. This period coincided with the development of shatterproof laminated safety glass and water-clear transparent plastic sheets that were lighter, more flexible, easier to shape, and less likely to shatter on impact. Aviation soon was a target market for these products.
Because the evolution of transparent window materials and plastic occurred on a similar trajectory, early aircraft – the production history of which is well known – are an opportunity to study developments in early transparent plastics. Written documentation of plastic products available at that time tends to come from manufacturers’ R&D reports, marketing materials, and advertisements, all of which offer valuable insight into what was available but may not coincide with what was used. The Smithsonian Museum Conservation Institute (MCI) and NASM teamed up to evaluate the potential of Raman spectroscopy to characterize the plastics that actually were used. Using these tools and X-ray fluorescence spectrometry we constructed a timeline for the development of aviator eyewear and aircraft window materials through World War II.
This research was funded by the National Park Service and the National Center for Preservation Technology and Training (Grant #MT-2210-10-NC-10).
Odile Madden is Senior Scientist of the Getty Conservation Institute’s Modern and Contemporary Art Research Initiative, which aims to improve understanding and conservation of new material technologies used in nineteenth- through twenty-first-century cultural heritage. Prior to joining the GCI in 2017, she was Research Scientist at the Smithsonian’s Museum Conservation Institute, where she studied the technological evolution of early synthetic plastics to improve their preservation. She holds a PhD in Materials Science and Engineering from the University of Arizona and a MA in History of Art and Archaeology and Advanced Certificate in the Conservation from New York University.