Why Don’t Airbus Aircraft Have Serrated Engine Covers?

We recently discussed planespotting and how to distinguish aircraft from one another. One defining feature of new generation Boeing jets is their serrated engine covers. Also known as chevrons, these are located on the back of the nacelle and are in place to reduce jet blast noise. Airbus has released some new aircraft since this technology was implemented by Boeing -but why don’t the European planemaker’s aircraft have this design?

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[thomas]

The fact that Boeing and GE ended the shevrons on the 777X for me just shows that this feature can't be so good otherwise they would use it there.

[theskyline]

Honestly this is a question I've never found a solid answer for.

[ksvarun]

Chevrons have a negative effect of increased drag
But also has an advantage of reducing sound insulation
It all depends on the balance

[hellboundslayer]

one would think he would mention the 777x not having serrated engine covers

[paulmurphy]

Excellent and so refreshing to find someone saying they just DON'T KNOW!

[luckyfernandasetiawan]

I feel like many airbus widebodies are pretty silent inside already. Especially A380 tho.

[quillmaurer]

Note that the 777X also doesn't have them, advantages must not be big enough to justify them in many cases.

[timothycook]

I don't know why, but I do know they look cool, especially on the newer 747

[zagstar]

I was literally just wondering this last night and here the video is. Weird!

[aviationchannel]

I think chevrons slightly increase the air resistance of the engine and Airbus found a way around the chevrons.

[nhathoang]

Having spent almost 2000 hrs on the A350 (piloting) and frequently travel the 787 (deadheading), I have to say the A350 is more quiet during cruise, but on take off roll the 787 is more gentle on your ears.
Generally, if Airbus can achieve the same end result as Boeing with their own patents and technology, why bother using someone else's.

[Jonathan-kiiz]

You should have mentioned that Boeing quietly removed its chevrons on the 777x.

[heemanOO]

Chevrons have little impact on noise reduction compared to manufacturing cost. That's why the latest B777X engines do not have these..

[Robwantsacurry]

Got a feeling it's to do with bypass ratio, the chevrons are there to mix high velocity air with lower speed airflow to lower noise, but at the expense of some thrust. The A320 NEO has a higher bypass engine than the 737 MAX, therefore the flow from the fan is already slower and less noisy.

[hdjdco]

Let's not forget 777-X doesn't have them either.

[jhmcd]

Airbus uses a combination of noise insulation and active noise canceling on their aircraft on the inside. This is fully evident if you look at the thick side walls on an A380. This may even be why they force airlines to get wider seats, as narrower seats wouldn't actually fit well in the cabin. Exterior wise they are just as loud as their older variants. They don't use it as they simply found an alternative to it. It should be noted the E170/175 also uses the chevrons on their engine nozzles. Also, their engines are computer controlled (well, nearly all engines are computer controlled) but contrary to popular belief, aircraft rarely use full trust to take off. So they could simply hold more thrust back at lower altitudes when able to help keep noise down. It works out to same effect for less cost.

[probableflaws]

It’s purely about marketing at this point. The chevrons have become the most identifiable part of the new Boeing planes. For Airbus to follow suit would make them seem to be behind the trend established by Boeing. By keeping the covers as they were Airbus can claim they made advancements in other areas of fuel savings and sound suppression and set their own path rather than followed someone else’s. With a duopoly on large planes these two companies always look for the least overlap so they can pry orders away from each other.

[edtad]

I know both aircrafts the A350 and the Boeing 787 closely; but in my experience the A350 produces less noise than that of B787 especially during approach!

I believe Airbus has found some hidden technology in noise abandonment in the A350 variants which made it more effective in suppressing noise than B787!

[longbeach]

It’s quite plausible to be a patent issue to a degree, as it relates to proven specifications that are effective. And the fact that Airbus were unable to incorporate an in-house design to a similar level of effectiveness, and even further at a hindrance. And as acknowledged, have found efficiencies by other means to remain competitive. Particularly with the A350.

[edwardhart]

Notice that the new 777X does not have chevrons....because their benefit was overstated.