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Comment by benj111 | Hacker News Reader

Ok I'm trying to parse that, and marry that with my own understanding.

The linked article seems to suggest that window corners weren't the cause of the crashes. My understanding is that corners can lead to propagation of cracks etc, thus why modern aircraft window have a large window radius. And large radius windows require less reinforcement, and thus weight.

They aren't contradictory are they?

Edit: Missing word.

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The hard rectangular angles lead to fatigue failure from stress concentration. If more testing had been done and this had been known during the design phase, it would have been possible to reinforce the rest of the airframe around the windows such that the airframe would be able to withstand the forces while retaining rectangular windows. No cracks, no crashes. However, the tradeoff for such strength would have been complexity, weight, and manufacturing difficulty; thus, modern airplanes have curved window ports to allow for windows while being light and simple. Aerospace and sports cars are the places in industry where lightness pays compounding dividends over raw strength. For a plane, if you can shave a pound off the design, you do it, since that's a pound you're not going to have to burn fuel to keep aloft for the entire lifetime of the aircraft. Or, for equivalent fuel, you could go faster instead.

I suppose there's another question I never asked myself: What is the merit of a rectangular window? Why would we want rectangles on our airplanes? They're on our houses because they're simple to frame and create openers for, neither of which are important for planes.

> What is the merit of a rectangular window?

less blind spots! cockpits in fact tend to maximize the window surface area and you'll find square/trapezoid on most of them. (counterpoint: SpaceShip One went for rounded windows because they maximized for strength).

Thanks for your input.

"What is the merit of a rectangular window" Marketing gimmick? Square panels = easier construction?

I was just trying to think of practical applications (planes), that led to trying to reason about whether this would solve the problem of fractures in this situation.

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