When you ask a small child to draw an airplane, they usually sketch little oval windows. But did you know that planes didn’t always have this design? The de Havilland Comet, one of the first commercial jets, actually had square windows. However, tragedy struck when three Comets crashed within just five years of their introduction. Investigations revealed that the crashes were caused by cracked window frames, a result of the square design. Square windows couldn’t handle the stress of high-altitude flying and increasing cabin pressure.
Despite this setback, flying at high altitudes is crucial for commercial flights. It reduces drag, saves fuel, and minimizes the environmental impact. Additionally, higher altitudes offer a smoother and more comfortable flight experience with less turbulence. Scientists are even exploring alternative fuels to further improve aviation’s environmental footprint.
So, what was the solution to the window problem? The answer was simple: swap those squares for ovals. Oval windows evenly distribute the pressure on the window, reducing the risk of cracking. “The narrowest part of the oval will be designed to ensure the curve does not generate unsafe stresses in the surrounding material,” explained Dai Whittingham, chief executive of the UK Flight Safety Committee.
Aside from safety, oval windows also have some superficial benefits. Designers prefer them because they provide a larger viewing area that accommodates passengers of different heights.
Curious to learn more about this engineering quirk? Check out this video by the YouTube channel Real Engineering, which explains the physics behind it:
An earlier version of this article was published in January 2016.
