Why is the airplane window oval?

Surely you will not be able to find a plane with a rectangular window. Let's join the BGR technology page to find out why.

The plane window has an oval shape.

As a product of decades of scientific and technological research, nearly every element on the aircraft has a reason to carry the shape and function as it is today. Even the plane window: the rectangular shape rounded by 4 corners or their oval is to help you be safe.

In the context of aviation becoming increasingly popular, the number of aircraft in the sky also increased. This forces airlines to push high altitude flying. In addition, when increasing the flight altitude , the air is also thinner, reducing friction, thereby saving fuel and reducing shock in the journey.

In order to raise the flight altitude, the cabin needs to be increased pressure, the fuselage should also be designed to reduce internal pressure.

In order to raise the flight altitude, the cabin needs to be increased in pressure; The fuselage should also be designed as a tube to reduce internal pressure. The first commercial passenger plane, de Havilland Comet, has the same design. Unfortunately, the window of the Comet is not as oval as it is but is usually rectangular. During the life cycle, Comet also had many pitiful accidents - and the reason for nothing other than window design was inappropriate.

So why does square design not fit? When the plane increases in height, the pressure inside the fuselage will gradually reach higher than the external pressure . This causes the fuselage to expand slightly, creating pressure on the material on the fuselage.

Pressure on the fuselage has no window (left) and has a rectangular window (right).

The engineers of the 1950s considered this, but what they did not realize was that letting the material under pressure for a long time would cause cracking. In the picture above, you will see the pressure on the fuselage without the window evenly spread, while the pressure on the fuselage with the window will change direction. This will cause the area around the four corners of the rectangular window to suffer the most.

The oval window design will not make any position suffer too much pressure.

In contrast, the oval window design will not cause a position to suffer too much pressure. This design came after engineers studied the remaining debris after the accidents that occurred with the Comet.

After the Comet accidents, de Havilland's opponents promptly switched to the oval window design.

After the Comet accidents, de Havilland's opponents promptly switched to the oval window design. The aircraft manufacturer cannot recover sales with the Comet 2 and Comet 4 generations and then became part of the Hawker Siddeley Group, now a BAE Systems consortium.