Wonder Why Airplane Windows are Round?
Sitting on a plane for the very first time is probably one of the fondest memories we have in our lives. Those who have been fortunate enough to fly above the clouds and look down upon the mind-blowingly beautiful scenery of the Earth below will know how blissful is the experience of flying. That said, remember how shocked were you, when you saw that the aircraft had small, round-shaped, triple-paned glass windows? These windows may compliment the stylistic, sleek cabin design, but don’t offer a full panoramic view. So, why are the plane windows have a round design anyway? Here’s why.
Earlier Plane Windows had Hazardous Corners
Throughout the years, aerospace engineering has tremendously improved the design of aircraft, although most of it is because of trial and error. In early aircrafts designs, square windows were the most conventional choice around the world. Engineers justified this particular design choice for windows, by saying that square windows were already the standard for trains and automobiles. However, this decision lacked an actual understanding of aerodynamic principles. As a result, two planes fell apart mid-flight because the corners of these square-shaped windows are vulnerable to stress and were further weakened by air pressure. Researchers later found that the window corners, combined with the pressure from high speeds and high altitudes, compromise the structural integrity of the aircraft.
The de Havilland Comet
The first-ever commercial jetliner in the world, the de Havilland Comet, took flight in the year 1949. In its first year of operation, the jetliner carried 30,000 passengers, including Queen Mother, Queen Elizabeth, and Princess Margaret. With the newer engines and better design, the plane was able to fly at altitudes above 30,000 feet and was able to take eight flights per week by the summer of 1953. In the year, however, the jetliner suffered two fatal crashes because of its square windows. Both Flight 781 and 201 had structural issues, and as a result, at least 56 people were killed. Researchers found that the window corners were vulnerable to high-pressure levels (the pressure at the corners was at least two to three times more than that of the remaining cabin space). This caused the fuselage to disintegrate, and eventually, the aircraft fell apart mid-air.
As a result of these crashes, engineers were forced to re-think and improve the window designs. Subsequently, oval windows we see today were incorporated into the design. Structurally, oval windows are better suited to disperse the stress and pressure more evenly on the plane. Additionally, these windows also have multiple panes along with a small hole near the bottom. While the first of the panes take on the pressure, the second one is there to safeguard the plane in case the first one somehow failed. The final pane, which is the closest to the passenger is known as the “scratcher” pane and prevents any damage to the other panes from reckless passengers. The small hole at the bottom of the window, or the “breather hole”, helps the window handle the pressure and keep everything intact.