How the bulletproof vest was conceived and improved over time

The bulletproof vest has already saved thousands of lives since the 19th century.

But it was in the sixties that this garment took on another dimension thanks to Kevlar, a synthetic fiber more resistant than the silk initially used, as David Castello-Lopes recounts, Monday at the microphone of Europe 1.

Bulletproof vests have today become essential elements to ensure the safety of law enforcement agencies or even heads of state.

But how were they invented?

David Castello-Lopes goes back, in the program Historically Vôtre, to the origins of this garment capable of saving lives, thanks to the use of very specific textiles. 

"The bulletproof vest, I must admit that for a long time I found it mysterious. I did not really see how a piece of clothing, even very strong, could stop a metal projectile going at 1,500 kilometers per hour.

Very heavy metal armor

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So where do these vests come from and especially how is it possible that they stop bullets?

For centuries, there are quite a few people in the world who have tried to make armor that can stop bullets.

And at first it was armor that looked a lot like knight's armor.

There is also the well-known example of an Australian bandit named Red Kelly who, with his gang in the 1880s, made a metal armor which he used with some success during his encounters with the police.

But the problem with these armors was that they weighed very very heavy, namely 25 kilos, which made the movements difficult.

But being able to move, when you are being shot, is as important as being physically protected from the bullets aimed at you.

Red Kelly and his friends made a mistake in thinking that metal was the best protection against bullets.

Why ?

To understand it, you have to explain a little bit what makes the power of a revolver bullet.

Korean use of cotton

A revolver bullet can go through walls - and even more so people's skin - because it concentrates a lot of energy at its point.

But most bullets have another characteristic: when they hit a surface, they deform.

And when they deform, they penetrate less easily because they are wider.

Yeah, if I try to fit the tip of that pen into my hand, I'm going to do it just fine.

On the other hand, this glass, which is much wider, I'm going to have a hard time because the force that I apply is diffused over a larger area.

It's the same reason that we dig less into the snow with snowshoes than with Stan Smiths.

So if we get the ball to deform before it hits a person's skin, then the energy of the ball will be able to be more easily dissipated.

And the first to realize this were the Koreans in the middle of the 19th century.

They showed that when you lay ten layers of cotton on top of each other, you could stop bullets from some guns of the day because those bullets warped before hitting the skin.

A few years later, independently, an American surgeon from the Wild West - who was called Georges Goodfellow - saw before his eyes a settling of scores with a revolver between two players, one of whom was shot in the heart. .

And when Georges approached to look at the wound, he noticed that the silk handkerchief the victim was wearing on his chest had not been punctured by the bullet.

The bullet had just pushed the handkerchief inside the victim's body.

It was therefore this observation that gradually led to the development of Western bulletproof vests, which were all made of silk.

The arrival of Kevlar, more resistant

Gangsters of the Al Capone era, for example, often wore bulletproof silk vests.

Heads of state around the world had them too, including Archduke Franz Ferdinand, who was assassinated in World War I, and who unfortunately was not wearing his on the day he was shot.

Even if fundamentally, it would have been useless since he was shot in the neck.

And then in the sixties, we invented Kevlar, which is a synthetic fiber more resistant than silk, but whose power to stop the balls works exactly on the same principle.

But the problem always remains the same in war: there is a fight between firepower and defense power.

So when the defense power increases, it encourages the creation of weapons that can surpass it.

Today, the American army's bulletproof vests, for example, are made of both Kevlar and metal or ceramic plates that are put inside.

And they save a lot of lives, since since 1973, it is estimated that 3,000 American police officers have been saved by their vests. "