hannahpa
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Is 747-8I As Quiet As The A380?

Tue Jul 31, 2012 11:20 pm

Just wondering if anyone here has flown LH's new 748. Does anyone know or have heard if the new 748 is as quiet as the A380??

Just wondering.

Thanks.
 
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Stitch
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RE: Is 747-8I As Quiet As The A380?

Tue Jul 31, 2012 11:41 pm

Haven't had a chance to fly an LH 747-8 as of yet, but they did put extra noise insulation in the nose so I am expecting it to be quieter than the 747-400.
 
hannahpa
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RE: Is 747-8I As Quiet As The A380?

Tue Jul 31, 2012 11:55 pm

Quoting Stitch (Reply 1):

Of course it is quieter than the 747-400.... I am wondering how it compares to the 380. Other than press release videos, I want to hear from people who have had the chance to fly both or who have heard from other people...
 
CM
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 12:43 am

Cabin noise is much quieter than the 744, but not quite as quiet as the A380. I think it's pretty clear Boeing is not interested in making an aircraft that quiet... They have as much as stated so publicly.

Incidentally, the 747-8 is certified to a lower community (QC) noise level on takeoff than the A380, and the same level for approach, so overall community noise from the 747-8 is lower.
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 1:10 am

Quoting CM (Reply 3):
I think it's pretty clear Boeing is not interested in making an aircraft that quiet... They have as much as stated so publicly.

In the same way Airbus didn't believe in 2 engines for long haul - the Boeing noise comments were nothing more than PR fluff...
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 1:19 am

Quoting bestwestern (Reply 4):
In the same way Airbus didn't believe in 2 engines for long haul - the Boeing noise comments were nothing more than PR fluff...

No, it was a very simple observation that there's an optimum background noise level and it's not zero. Despite the refusal of some people to acknowledge something that's not exactly rocket science.
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CM
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 1:31 am

Quoting bestwestern (Reply 4):
nothing more than PR fluff

As Nomadd22 noted, making an airplane quieter is not rocket science. Both companies know how to do it. However, they have each valued "quietness" differently. I've worked designing airplanes for Boeing for a long time, I can tell you Boeing has set defined targets for how much noise in the cabin is acceptible. If a design exceeds this target, Boeing will reduce weight by removing sound dampening material and let the noise increase to the target level. In fact, there was a time they actually considered adding white-noise generators in the forward cabin of the 787 because they feared it would be uncomfortably quiet.
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 1:56 am

Quoting CM (Reply 6):
As Nomadd22 noted, making an airplane quieter is not rocket science. Both companies know how to do it. However, they have each valued "quietness" differently. I've worked designing airplanes for Boeing for a long time, I can tell you Boeing has set defined targets for how much noise in the cabin is acceptible. If a design exceeds this target, Boeing will reduce weight by removing sound dampening material and let the noise increase to the target level. In fact, there was a time they actually considered adding white-noise generators in the forward cabin of the 787 because they feared it would be uncomfortably quiet.

Uncomfortably quiet? Normally you would think passengers would appreciate a really quiet environment, but then again some noise to drown out stupid conversations, babies/children crying & screaming, etc. would be missed. On a related note, I also miss loud takeoffs, but that's progress I guess.
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 2:15 am

It's always been an interesting debate. I'm fond of the gentler background noise on the 320 series vs. the 737, as with the 330/340 series compared to the 777. But damn if I don't get my rocks off staring at 100K+ thrust turbines for 10 hours vs. needle-dick 340 turbines. From a novice standpoint I think there's also something fundamental about the physics of massive turbines closer to the fuselage that no amount of sound dampening can overcome. A massive twin like the 777 or upcoming 350 cannot possibly be made more quiet than a 380 with same generation materials. Maybe I'm mistaken but the placement of the 380 engines, combined with their thrust and aircraft speed, make the 380 a cinch to take this dubious crown. As for me, I'm in the camp that likes at least some moderate ambient noise. And in my book the sweetest has always been the RR 767s. SImply the most wonderful aircraft interior ambiance ever made, wide and cozy at the same time.
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 2:32 am

Quoting CM (Reply 3):
Incidentally, the 747-8 is certified to a lower community (QC) noise level on takeoff than the A380, and the same level for approach, so overall community noise from the 747-8 is lower.

Could you find a source for that, they are both QC2 for take off as far as I know.
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blue100
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 2:40 am

Quoting dampfnudel (Reply 7):
Uncomfortably quiet? Normally you would think passengers would appreciate a really quiet environment, but then again some noise to drown out stupid conversations, babies/children crying & screaming, etc. would be missed. On a related note, I also miss loud takeoffs, but that's progress I guess.

I tend to fall into the camp that likes the noise. Of all long haul aircraft that I have flown, I've easily flown on the 777 the most and I really enjoy my trips on it. I'm not bothered at all by the noise of a 777 and in fact, it makes it much easier for me to drown out any background noise that may otherwise disturb me. In contrast, the one time I flew on an 333 longhaul (AY), it was noticeably quieter in the cabin, which made the sounds of children or chatter much easier for me to hear.

Quoting CM (Reply 6):
As Nomadd22 noted, making an airplane quieter is not rocket science. Both companies know how to do it. However, they have each valued "quietness" differently.

Agreed.   
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 2:50 am

Quoting BoeingVista (Reply 9):
both QC2 for take off

They are. ICAO certified noise levels (peak lateral) for the three aircraft are published as...

744 - 100 dB
A380 - 94 dB
748 - 93 dB

[Edited 2012-07-31 20:08:37]
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 3:28 am

Quoting CM (Reply 6):
In fact, there was a time they actually considered adding white-noise generators in the forward cabin of the 787 because they feared it would be uncomfortably quiet.

Actually this is exactly a big plus in my books. My very first A380 flight was on a QF one on the upper deck. It was just way way way too quiet up there. Now i would have thought that was a plus... my thinking being that the sound coming through the electronic headseats...even with noise cancelling would have been a higher quality adding to my experience. What I discovered was unexpect. I had two wealthy middle aged cougars sitting behind me drinking copious amounts of QF's finest bubbles, and as the flight continued they got louder and louder and louder. Now I have had plenty of experiences before on the old 744 with this same situation. After all, after getting a few into them plenty of businessman have been known to gasbag into all hours of the night across the pacific. The difference was, both the airframe and engine noise drowned them out more. It didn't disturb you. So I have to say I think Boeing is right and Airbus, stuck too much insulation in the A380. The noise cancelling headsets provided a similar experience in both so my initial hopes for a better entertainment experience didn't amount to much, but I did have to endure a conversation about what the cougars were gonna have their 'toy boys' do to them once they got to Los Angeles! I tell you what... give me the engine noise anyday!
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 3:55 am

Quoting nomadd22 (Reply 5):
No, it was a very simple observation that there's an optimum background noise level and it's not zero.

Then pipe in pleasing sound. Noise is that. Noise. Ocean waves... classical music...

Quoting blue100 (Reply 10):
I tend to fall into the camp that likes the noise.

I'm in the opposite camp.

Quoting Lufthansa (Reply 12):
The difference was, both the airframe and engine noise drowned them out more. It didn't disturb you. So I have to say I think Boeing is right and Airbus, stuck too much insulation in the A380.

You do realize that the dB level in your noise cancellation headsets to drown out their noise would be the same? Because it is quieter, it seems louder. That is a given. I have no trouble 'tuning out' other people though. If it is an issue, I have ear plugs in my bag anyway.   

Quoting CM (Reply 6):
Both companies know how to do it. However, they have each valued "quietness" differently.

   And we'll see which is the preferred method. There are several ex-Douglas aircraft I try to avoid due to the high noise levels. But to each their own. Pulling out insulation to save fuel has a plus.

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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 4:22 am

Quoting nomadd22 (Reply 5):
No, it was a very simple observation that there's an optimum background noise level and it's not zero. Despite the refusal of some people to acknowledge something that's not exactly rocket science.

This is well known - a standard problem in acoustic planning for work places.

Quoting CM (Reply 6):
In fact, there was a time they actually considered adding white-noise generators in the forward cabin of the 787 because they feared it would be uncomfortably quiet.

Again - a well known problem. Just a new one to aircraft.

Quoting dampfnudel (Reply 7):
Uncomfortably quiet? Normally you would think passengers would appreciate a really quiet environment, but then again some noise to drown out stupid conversations, babies/children crying & screaming, etc. would be missed. On a related note, I also miss loud takeoffs, but that's progress I guess.

It is also important to realize that noise canceling headphones will not cancel this kind of noise (they may insulate against it like ear muffs or plugs, but not cancel it). The reason is physics. Noise canceling headphones work by _predicting_ future noise based on existing noise and producing an out of phase 'noise' that cancels it. If the actual noise varies from the prediction, they do not work. Voices cannot be predicted in regard - so you cannot cancel them - only insulate against them or hide them in background noise (white noise).
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 4:24 am

Quoting dampfnudel (Reply 7):
Uncomfortably quiet? Normally you would think passengers would appreciate a really quiet environment, but then again some noise to drown out stupid conversations, babies/children crying & screaming, etc. would be missed.

Everyone (I think) acknowledges that there is a thing as too quiet. If it was library-quiet inside the cabin you'd hear *everything* your neighbors were doing and nobody wants that. The debate is just over what's the lowest noise level that's "enough".

If you take it to the extreme (anechoic chambers) it *really* freaks people out because your subconscious can't deal with not having acoustic cues about your surroundings.

Quoting wingman (Reply 8):
A massive twin like the 777 or upcoming 350 cannot possibly be made more quiet than a 380 with same generation materials.

It can. It's just far too large a weight penalty to be worth it. Technology exists, right now, to make any airplane cabin arbitrarily quiet. It's just not worth it.

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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 6:43 am

Quoting tdscanuck (Reply 15):
If you take it to the extreme (anechoic chambers) it *really* freaks people out because your subconscious can't deal with not having acoustic cues about your surroundings.

This is very true. Having worked in a few sound studios, most people have an adjustment period to get used to the complete absence of echoes...which they don't realise are everywhere...and provide much more noise to the background than most people think.
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masi1157
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 7:37 am

Quoting Lufthansa (Reply 12):
So I have to say I think Boeing is right and Airbus, stuck too much insulation in the A380.

Be assured they didn't. Low cabin noise levels are not primarily achieved by adding insulation, that is just one of many means. And insulation is rather light.


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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 7:48 am

Quoting CM (Reply 6):
As Nomadd22 noted, making an airplane quieter is not rocket science.

Don't agree with that. The point is making the plane quieter without adding to much weight. Airbus has spend years on research to find a insulation which is very light but also noise dampening.

I'ts based on cork AFAIK. That's why the A380 has a unrivaled quiteness and i prefer that over a noise enviroment.
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masi1157
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 7:55 am

Quoting autothrust (Reply 18):
I'ts based on cork AFAIK.

No, it isn't.


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CHRISBA777ER
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 8:14 am

I do wonder how many posters would be saying the A380 is too quiet if the 748i was quieter.

It probably isnt, but thats by-the-by. My personal view is that I much prefer the A380 over any other long-haul aircraft, in fact any other plane full stop. I go out of my way to fly on it, indeed i've paid a lot more in a couple of cases to make sure i got the A380.

I love the 77W, and I've flown on it more than any other plane save for the A320. But i prefer the A380 cabin experience. I'm looking forward to trying the 748i - my guess is it will be roughly A343 or A346 sort of quiet, meaning, absolutely lovely and a very very pleasant place to spend 12 hours.
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sweair
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 8:15 am

If the cabin is quiet like on the 787 you will hear other sounds like electric motors or someone farting etc..

Look for a landing clip filmed in a ANA 787 on YouTube, you can hear some motors more than the engine, that is probably worse IMO.
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 8:18 am

Quoting CM (Reply 3):
I think it's pretty clear Boeing is not interested in making an aircraft that quiet... They have as much as stated so publicly.

I call bollocks on the Boeing statements regarding noise. Most every passenger I've talked to really enjoys the quiteness of the A380. Rest assured that if Boeing had a similarly quite aircraft, they would tote that as a great achievement.

It's much the same as Airbus "not believing" in composites, until they start the A350, or Virgin "not believing" in twins until they acquire A330s, or Lufthansa "not believing" in the value of PTVs until they, well, have them themselves. Or as a non-aviation example, look to Apple. Every feature their products don't have is declared to be totally unnecessary, even harmful, until they adopt it themselves.

Rest assured that Boeing will one day build a clean-sheet design, make it super-quiet, and market it as the "Silence Liner" or something. I guess "WhisperJet" is taken..
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 8:36 am

Most office environments have significant background noise from computers (largely fan noise) and become eerily quiet during a power failure. The background noise in modern aircraft is now getting down to similar levels which should be more than enough for most pax.


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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 8:43 am

Interesting how Boeing is 'not interested' in making their aircraft more quiet when Airbus has the quieter aircraft. If it was the other way around, then I'm sure a lot of people would say Boeing got it right and Airbus is behind.

Quoting Rara (Reply 22):

Well said!
 
masi1157
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 8:46 am

Quoting StickShaker (Reply 23):
The background noise in modern aircraft is now getting down to similar levels which should be more than enough for most pax.

That would be still quite a way to go. The gap is still 10-30dB(A), and it won't become smaller in the near future.


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Burkhard
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 8:55 am

Quoting nomadd22 (Reply 5):
No, it was a very simple observation that there's an optimum background noise level and it's not zero. Despite the refusal of some people to acknowledge something that's not exactly rocket science.

This optimum is different for different societies. Southern Europe and the US is used to much higher noise levels than Central and Northern Europe as example, whicj explains that A and B find a different optimum each.

Now we just are starting to understand what it wrong with permanent and long term noise in the 60dB region, which deseases are triggered by it (Alzheimer a candidate), and which diseases are triggered by short high level noise above 70dB (Strokes are candidate). In the end all science is rather sure about that below 49dB does not make you ill, and all above 55 can do so.
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 9:00 am

Ok so If you know me I have an affinity of the BA744 so I took a video of it to compare to the 748:

https://www.youtube.com/watch?v=T7u2c9Mg04I BA744
https://www.youtube.com/watch?v=LtaxHCt3MOo 748

Now here's an A380 video I found filmed from a similar position:
https://www.youtube.com/watch?v=WGLzg0tND6s ← skip to 0:40 and you can compare to the other two
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konstantinkoll
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 10:02 am

I've been on Lufthansa's 747-8i about a month ago, and found the aircraft to be amazingly quiet, however I lack the comparison to an A380. You can read more about my flight on the 747-8i here: http://flightmap.net/blog/102-trip-fraiad
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masi1157
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 11:02 am

Quoting Burkhard (Reply 26):
This optimum is different for different societies. Southern Europe and the US is used to much higher noise levels than Central and Northern Europe as example, whicj explains that A and B find a different optimum each.

Cabin noise targets have never been set with such cultural differences in mind, I believe. And I even believe it came as a surprise for almost everybody at Airbus, that the A340 cabin was so quiet. But once it was there, they happily used it for advertisements.

Quoting konstantinkoll (Reply 28):
You can read more about my flight on the 747-8i here:

You only mention engine spool-up there. But what about the continuous brodband noise during cruise? OT: Are you sure the flight DUS-FRA was on a B737-400?


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spink
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 11:56 am

Quoting autothrust (Reply 18):
I'ts based on cork AFAIK.

Unlikely. Almost all noise barriers are make up of either polymer foam based material or high density polymer based material depending of the characteristics that are desired.

Quoting masi1157 (Reply 17):
And insulation is rather light.

Depends on the frequencies one is wishing to dampen. Light aircell foam based materials work well against higher frequencies but it requires dense heavyweight materials to provide dampening against lower frequencies. There are also a lot of weight vs volume tradeoffs that can be made as well.

Also due to perception issues, frequency of noise can have a bigger impacted on perceived noise levels than actual sound pressure of the noise. Does anyone have a resource for full frequency weighted SPL measurements for various aircraft?
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 12:46 pm

Quoting CM (Reply 11):
They are. ICAO certified noise levels (peak lateral) for the three aircraft are published as...

744 - 100 dB
A380 - 94 dB
748 - 93 dB

That is incorrect.

The Noise TCDS for the 747-400 (RB211-524G3-T-19 engines) says 396,893 kg takeoff and 285,763 kg landing

Lateral EPNL 98.0
Flyover EPNL 99.2
Approach EPNL 103.4

Takeoff QC = 98.6, therefore QC 4
Landing QC = 94.4, therefore QC 2

The Noise TCDS for the 747-8 says 447,696 kg takeoff and 312,072 kg landing

Lateral EPNL 94.0
Flyover EPNL 94.5
Approach EPNL 100.4

Takeoff QC = 94.25, therefore QC 2
Landing QC = 91.4, therefore QC 1

http://www.easa.eu.int/certification...28IM%29_Boeing_747-07-15122011.pdf


The Noise TCDS for the A380-841 says 569.000 kg takeoff and 391.000 kg landing (This is the highest GW variant certified)

Lateral EPNL 94,2
Flyover EPNL 95,6
Approach EPNL 98,0

Takeoff QC = 94.9, therefore QC 2
Landing QC = 89.0 , therefore QC 0.5

http://www.easa.eu.int/certification...-A.110_Airbus_A380-06-09062011.pdf
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masi1157
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 12:55 pm

Quoting spink (Reply 30):
Unlikely. Almost all noise barriers are make up of either polymer foam based material or high density polymer based material depending of the characteristics that are desired.

It is mostly glasswool in Airbus A/C.

Quoting spink (Reply 30):
Depends on the frequencies one is wishing to dampen. Light aircell foam based materials work well against higher frequencies but it requires dense heavyweight materials to provide dampening against lower frequencies. There are also a lot of weight vs volume tradeoffs that can be made as well.

As I said, it is mostly glasswool, and that works rather well in mid and high frequency ranges, and even as low as say 200Hz there is a little benefit.

Quoting spink (Reply 30):
Does anyone have a resource for full frequency weighted SPL measurements for various aircraft?

You mean cabin noise? Yes. But I can't tell you the numbers.


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caljn
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 1:25 pm

Very amusing how some hear equate sound levels with superiority or quality. As others have said above, if quiet were the issue it could be accomplished very easily.
And as another said, the 767 has easily the most comfortable cabin environment...good space and sound altogether.
 
masi1157
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 1:29 pm

Quoting caljn (Reply 33):
As others have said above, if quiet were the issue it could be accomplished very easily.

Would you tell me the trick how to do that without adding weight? And I mean no weight at all.


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mogandoCI
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 1:32 pm

If airlines really cared about cabin quietness, choosing A380 over 747-8 is not the answer. A baby screaming in first class on the A380 is far noisier than a fully asleep cabin on the 707.
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 1:35 pm

Quoting masi1157 (Reply 17):
Be assured they didn't. Low cabin noise levels are not primarily achieved by adding insulation, that is just one of many means. And insulation is rather light.
Quoting masi1157 (Reply 32):

It is mostly glasswool in Airbus A/C.

"Glasswool" AKA fiberglass insulation. Sometimes, polyester (or similar) fiber is used because of lighter weight.
Sometimes light weight foam cell pads are bonded on to the skin for the lower frequencies (engine noise).

Note that the A380 has Glare (aluminum, fiberglass laminate) which probably contribute to the sound dampening.

The 787 and A350 will probably have different sound characteristics because of the composite skin.

Has anyone flown a a small corporate jet? I would suspect they spend more money and weight to take out the noise on those aircraft.

bt
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masi1157
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 1:52 pm

Quoting bikerthai (Reply 36):
"Glasswool" AKA fiberglass insulation. Sometimes, polyester (or similar) fiber is used because of lighter weight.

As I said: "Mostly" glasswool. But I never heard of ...

Quoting bikerthai (Reply 36):
Sometimes light weight foam cell pads are bonded on to the skin for the lower frequencies (engine noise).

I did hear of constraint damping layers, which are not really light weight. And they are not appreciated by the skin inspection guys.

Quoting bikerthai (Reply 36):
Note that the A380 has Glare (aluminum, fiberglass laminate) which probably contribute to the sound dampening.

Unfortunately that is negligible.

Quoting bikerthai (Reply 36):
The 787 and A350 will probably have different sound characteristics because of the composite skin.

And so is this.


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JAAlbert
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 1:54 pm

I've long felt that the cabin noise of aircraft in flight is very wearying over time. I am in the camp for a quieter cabin.

That being said, the topic of this thread requested a comparison between the cabin level noise of the 380 and 748. Lots of interesting discussion, but almost no responses devoted to the question at hand. Surely more A-net folks have flown both aircraft and can chime in!
 
CM
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 2:04 pm

Quoting Rara (Reply 22):
I call bollocks on the Boeing statements regarding noise.
Quoting AirPacific747 (Reply 24):
Interesting how Boeing is 'not interested' in making their aircraft more quiet

I do not work in an acoustic engineering role, but I have seen with my own eyes Boeing revising the airplane when the design was over-performing to targets for cabin noise. I'm sure it seems odd in an environment where Airbus actually markets the quietness of their cabins, but Boeing truly has set a line which they feel is too quiet.

Quoting JAAlbert (Reply 38):
Surely more A-net folks have flown both aircraft and can chime in!

I've flown on the upper deck of the A380 and found the noise level (or lack thereof) to be fine. However, occasionally on a long haul flight you will experience someone snoring loudly across the cabin, or a baby crying, or people talking when everyone is trying to sleep. I use ear plugs, but even these are not always adequate to deal with some cabin noise. These problems are aggravated when the background noise is reduced.

For those who think this "too quiet" argument is all marketing "bollocks", then apparently Boeing has pretty far-reaching tentacles in their marketing:

http://www.flightglobal.com/news/art...-after-crews-find-a380-too-319698/
http://gizmodo.com/5106074/airbus-a3...-quiet-eliminates-precious-privacy
http://blog.seattlepi.com/aerospace/...03/sleeping-pilots-a380-too-quiet/
http://www.wired.com/autopia/2008/12/a380-is-so-quie/
http://www.theage.com.au/travel/a380...leepless-pilots-20081205-6s1x.html

Quoting masi1157 (Reply 34):
Would you tell me the trick how to do that without adding weight?

  This part indeed is rocket science!

Quoting zeke (Reply 31):
That is incorrect.

Interesting. Did EASA require separate community noise tests from those done for the ICAO noise cert? Most of those numbers differ from the ICAO cert by around a dB. EASA is actually showing the 748 better and the A380 worse than the ICAO numbers.

[Edited 2012-08-01 07:07:39]
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 2:18 pm

Quoting CM (Reply 39):
For those who think this "too quiet" argument is all marketing "bollocks", then apparently Boeing has pretty far-reaching tentacles in their marketing:

All those quotes are 4 years old and not about noise in the pax cabin, but in the flight crew rest area. That problem has long been solved.


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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 2:26 pm

Many large office spaces here in Canada have been install white noise generators as of late to drown out the ambient noise of everyday office life. I have yet to fly in the A380 myself, but if it is quieter than an A330/340, then for myself, it would be approaching the to quiet territory. Having said that, I am the type of person that needs back ground noise to sleep. Give me the sound of those 2 giants on a 777 anyday!

And this isn't an A vs. B so you can all relax.............just a personal preference.
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 2:34 pm

Quoting CHRISBA777ER (Reply 20):
My personal view is that I much prefer the A380 over any other long-haul aircraft, in fact any other plane full stop.

Like you, I love the 777, but I will take an A380 any day anywhere.

I know you are also a fan of the 747, but I personally dislike the plane. However, with the 747-8, LH have addressed my two biggest complaints with the platform - they didn't cram the nose full of suites and they added additional noise insulation to quiet the environment. As such, I do intend to try it and I hope I like it as much as I do the 777.   

[Edited 2012-08-01 07:35:12]
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 3:16 pm

Quoting Rara (Reply 22):
I call bollocks on the Boeing statements regarding noise. Most every passenger I've talked to really enjoys the quiteness of the A380. Rest assured that if Boeing had a similarly quite aircraft, they would tote that as a great achievement.

I'm having a hard time finding the "bollocks" in the statements being discussed here. Boeing folks are saying that they can make the cabin quieter, but they've decided that they'd rather put the development effort and cost of extra weight into other things, and suffer a somewhat louder cabin. Are you saying Boeing just doesn't know how to make the cabin quieter than the 787? If so, on what basis do you make this statement? If not, what are you saying?
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 3:54 pm

Quoting Rara (Reply 22):
I call bollocks on the Boeing statements regarding noise. Most every passenger I've talked to really enjoys the quiteness of the A380. Rest assured that if Boeing had a similarly quite aircraft, they would tote that as a great achievement.

I expect they would. But as Revelation notes directly above me, if anyone is of the opinion that Boeing commercial aircraft have a subjectively/objectively higher interior noise level than an Airbus commercial aircraft is because Boeing is unable to design a quiet interior environment should reconsider that opinion.

Even with a quieter cabin and one less seat per row, Boeing rolled out survey after survey where the 777 was the preferred flying experience by those polled. *shrug*

The A380's quietness comes in no small part to being so big and having four quiet engines. The 747-8 no doubt gains similar benefits from it's size and, especially, it's quiet GEnx engines.

I am interested to see what interior noise levels are like between the A350-1000 and the 777-9X, as both will have two large ~100k thrust engines mounted close to the airframe.
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 3:56 pm

Quoting CM (Reply 3):
Incidentally, the 747-8 is certified to a lower community (QC) noise level on takeoff than the A380, and the same level for approach, so overall community noise from the 747-8 is lower.

Amazing! The A380 is near silent on approach, very quiet reverse thrust.
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 4:18 pm

Quoting masi1157 (Reply 32):
It is mostly glasswool in Airbus A/C.

So they are basically just reusing their thermal insulation. That will take care of high frequency reasonably well but isn't that great for mid and low frequency sound.

Quoting bikerthai (Reply 36):
Sometimes light weight foam cell pads are bonded on to the skin for the lower frequencies (engine noise).

That sounds more like vibration dampening.
 
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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 5:05 pm

Quoting Flighty (Reply 45):
Amazing! The A380 is near silent on approach, very quiet reverse thrust.

The data Zeke posted suggests the 748-i is marginally quieter on takeoff, and marginally noisier on approach.
No data on interior noise anywhere, sadly.

Quoting Stitch (Reply 44):
I expect they would. But as Revelation notes directly above me, if anyone is of the opinion that Boeing commercial aircraft have a subjectively/objectively higher interior noise level than an Airbus commercial aircraft is because Boeing is unable to design a quiet interior environment should reconsider that opinion

Like anything else it will be a trade-off. I'm assuming that aircraft customers have interior (as well as exterior) noise requirements too. If you're well inside them, then it makes sense to optimise the weight.

On the other hand, it's entirely possible that some, or many, customer airlines find that they can make an economic argument for their "flagship" A380's having a noise level commensurate with its status (i.e. they find enough people will make a user-chooser choice to justify the extra weight)

These things are always trade-offs, and the surrounding circumstances will determine which way the trade-off falls  

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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 5:10 pm

Quoting spink (Reply 46):
So they are basically just reusing their thermal insulation. That will take care of high frequency reasonably well but isn't that great for mid and low frequency sound.

By selecting the density and thickness you can tune it quite well to mid frequency, at least. In low frequency it is poor, just like anything having low weight.

Quoting spink (Reply 46):
That sounds more like vibration dampening.

True, but it is the transmission path both for engines' exhaust jet noise and boundary layer noise.



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RE: Is 747-8I As Quiet As The A380?

Wed Aug 01, 2012 5:18 pm

Quoting astuteman (Reply 47):
On the other hand, it's entirely possible that some, or many, customer airlines find that they can make an economic argument for their "flagship" A380's having a noise level commensurate with its status (i.e. they find enough people will make a user-chooser choice to justify the extra weight).

As you know, I'm a massive fan of the A380 as a passenger plane. And it is my preferred way to travel by air.

But the A340 having a quieter cabin than the 777 didn't make an economic argument for buying the A340 and the A320 having a quieter cabin than the 737NG has certainly not provided an economic benefit strong enough to handily out-sell the 737. And the 747-8 seeming to be quieter than the 777-300ER has certainly not restored the Queen to her throne against her younger sister.

A quiet cabin is certainly a benefit for the A380 and I am sure airlines sell that as part of the overall "A380 experience". And I certainly value that experience when flying the A380 and that value does have some economic benefit to A380 operators in that I'm willing to spend a bit more for the A380 over other planes (especially the 747-400).

The A380 could have the loudest cabin and yet I believe it would sell just as well as having the quietest thanks to also having the cheapest seat-mile costs. That is the real economic argument.  

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