飛機舷窗爲何是圓形的

While not everyone will have pondered the subject while staring out of the Window during a flight, the question as to why aeroplanes have circular windows rather than square ones is interesting.
雖然不是每個人都會在飛行中凝視窗外的時候思索一個問題：爲什麼舷窗是圓形的而不是方形的。但這個問題很有趣。

Over the years, aerospace engineering has made huge leaps in aeroplane technology, meaning planes can carry more passengers and go faster. The planes have also changed shape to increase safety – including the windows.
多年來，航空航天工程在飛機技術上取得了巨大的飛躍，這意味着飛機可以運載更多的乘客，飛行速度更快。同時，爲了提高飛機的安全性，飛機在外形上也做出了相應的改變。舷窗，便是變化之一。

In the 1950s, when jetliners were starting to become mainstream, the De Havilland Comet[1] came into fashion. With a pressurized cabin, it was able to go higher and faster than other aircraft.
20世紀50年代，噴氣式客機開始成爲主流，德·哈維蘭“彗星”客機便是當時的主要機型。增壓座艙的誕生使得噴氣式飛機可以比其他飛機飛得更高更快。

[1] 德·哈維蘭“彗星”客機，由英國哈維蘭公司研發，於1949年出廠的噴氣民航客機，是世界上第一種以噴氣發動機爲動力的民航客機。

However, the plane had square windows and in 1953 two planes fell apart in the air, killing 56 people in total.
然而，該機型舷窗是方形的，1953年，該機型兩架客機在空中解體，共造成56人死亡。

The reason for the crashes? The windows.
悲劇發生的原因是什麼？答案是：舷窗。

Where there’s a corner, there’s a weak spot. Windows, having four corners, have four potential weak spots, making them likely to crash under stress – such as air pressure.
哪裏有拐角，哪裏就有弱點。方形舷窗有四個角，就有着四個潛在的薄弱點，使它們很可能在壓力作用下破裂，比如大氣壓力。

By curving the window, the stress that would eventually crack the window corner is distributed and the likelihood of it breaking is reduced.
因此，讓窗緣線條彎曲，來分散窗口四角的壓力，從而降低了窗戶破碎的可能性。