• Chevrons, or dented edges on aircraft engines

    What are them? What are they for?

What are those dented edges some aeroplane engines have on their rear ends? Have you ever seen them? Have you ever asked yourself what they’re for?

You already know the aviation world is always investigating sustainability and trying to make aeroplanes quieter, don’t you?

In today’s post we explain the new design being used by manufacturers of aeronautical engines: chevrons.

Chevrons: A NASA‘s contribution to aeroplanes’s engines

The first thing to keep in mind is chevrons are NASA’s contribution to the world of civil aviation. In the 90s, NASA carried out a series of computer simulations in order to find a design that would reduce noise pollution produced by engines.

Well, after several tests and attempts, both in laboratory as well as in test banks, the conclusion reached was that the most efficient design was what’s called a chevron, nothing other than waves on the leading edge of airflow on an engine. It may seem absurd, right? Well, it isn’t and let’s explain why.

Why do chevrons reduce engine noise?

The majority of the generated noise is produced when combining the flow of hot air moving within the combustion chamber with the air on the outside. The purpose of chevrons is to make this mixture as soft as possible in such a way that noise is reduced.

This technology is currently only being used by the American manufacturer Boeing but its patent will eventually be sold to others.

The use of this technology also accounts for the decrease in noise insulation used in aeroplanes. For example, in the case of the B777, this reduction goes up to 270 kilograms, which also generates a substantial fuel saving.

An additional technological advance associated with chevrons is the use of memory foam materials. This makes the cover of the engine change its shape as temperature varies, so that the take off and landing phases are much more efficient. Once engines are cruising, it becomes colder and returns to its original shape.

Boeing 787 Dreamliner, the 777X and 737 Max were the first aircraft to incorporate this novel technology.

Why are aircraft chevrons called this way?

Boeing named them, making reference to a symbol used in military shields and emblems with a spear pointing upwards. This symbol is used by the American navy to indicate their soldiers´ ranks.

So the next time you see a dented engine you’ll know it’s chevrons and that they are termed so because of US soldiers.

We hope this post has helped you learn a little more about new techniques the aeronautical industry is using to minimise carbon footprints.

If you’d like to learn more about aviation, we suggest you continue surfing our aviation blog to find out many other aeronautical topics.

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