If there are any children reading this, there's really only one thing we want to tell you about adulthood: If you make one tiny mistake, people will die.
Don't believe us? Let us share these tales of completely forgivable design mistakes that cost lives.
6An Airliner Crashes Due to Square Windows
In the 1950s, companies were making the first foray into jetliners, and leading the pack was the de Havilland Comet. It was a state-of-the-art jet with many never-before-seen features, such as a pressurized cabin that allowed it to fly higher and faster than other aircraft.
Unfortunately, in 1954, two Comets disintegrated midflight for no apparent reason, killing 56 people total. In retrospect, the name "Comet" was a bad choice.
Although it was superior to de Havilland's first choice, the "Murder Bird."
The Laughably Simple Flaw:
It had square windows.
This is one of those things that is easy to miss (the designers missed it, for instance) but easy to understand once it's explained.
Here's a Kit Kat style candy bar. Where would you say this thing is most likely to break when pressure is applied?
Along the willpower line, probably.
Right there at those sharp notches, obviously. That's why they're there, and it's why no one builds important structures out of Kit Kats.
Well, a square window is made up of four 90-degree notches cut out of your wall, creating four of these weak points. You don't need a diagram -- if you have brick or stucco on your house, go outside and look. You'll find cracks there, protruding right from one of those sharp corners:
To fix, place head in bucket of sand and hum loudly.
In engineering, that sharp corner (or groove in the Kit Kat) is called a "stress concentration," a spot where the shape of the object makes it more likely to break under stress.
You don't want the red bit.
So if you're an airplane maker, how the hell do you fix that?
Well, have you ever noticed how on every plane you've ever been on, the windows you look out of have rounded corners? Those curves are pretty much the only thing keeping the plane from tearing itself apart in midair like in that scene from Fight Club. It distributes the stress to all of the various points along the rounded curve, rather than on that one sharp corner, which otherwise would (as they found out) tend to pull apart and form a crack over time.
Trust us, this was not easy to figure out. Experts had no idea why the planes weren't holding together until they tested the structure by simulating the repeated pressurization of the cabin. Sure enough, the fuselage eventually burst like a bootleg condom, and the break started with cracks right at those window corners.
Getty / plane-crazy
Top: Safe and enjoyable ride. Bottom: Explosive Caesarean section.
Representatives from competing companies Boeing and Douglas both said that their engineers hadn't thought of it either, and that if the Comet hadn't been first, it would have been one of theirs that crashed. Planes have had windows with rounded corners ever since.