We are used to seeing square and rectangular windows in most building structures. And there are, of course, rounded windows that provide a different design. For example, in the case of airplanes, these are exactly the ones we find. Although it may seem for aesthetic reasons, there is actually a reason for this. So do you know why airplane windows are rounded?
Do you know why airplane windows are rounded?
Initially, square windows were, in fact, the norm in early commercial aircraft manufacturing. They've worked great for centuries in homes and buildings, so why change a perfectly good design?
Unfortunately, it took some tragic events for engineers to look again at the design of airplane windows. It was in the 1950s that commercial planes were getting bigger – and they also started to disintegrate in mid-air. Two of these planes were de Havilland Comets, which disintegrated mid-flight in separate events in 1953 and 1954. It turned out that the cause was… yes, the square windows.
Engineers determined that the sharp corners of the planes' square windows created natural weak points, causing “metal fatigue failures.” These corners were easily subjected to stress and then further weakened by high-altitude air pressure.
In the 1950s, some planes flew faster and higher than their predecessors, which meant that after several flights and repeated pressurization, the square windows would collapse under the pressure.
Rounded windows, on the other hand, are able to distribute pressure evenly because they have no corners where stress is concentrated, reducing the likelihood of cracks or breaks. Circular shapes are also stronger and resist deformation, making them better able to withstand repeated pressure differences between the inside and outside of the plane.
Multi-layer windows
You may also notice that there are several layers of acrylic (not glass) between you and the outside of the plane. These layers offer additional protection against weather events such as rain, wind and fog. And that little hole at the bottom? They're called “bleed holes” and they add another layer of protection, helping to keep the air pressure on board at a relatively constant level, allowing air to pass through the various layers of the window.
So the next time you're on a flight, be thankful for the rounded windows, whether you're enjoying the view or avoiding it because you don't want to be reminded of how high you are off the ground.