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Is The 787 More Quiet Than The A380 Both RR And GE  
User currently offlineAeroflot001 From Argentina, joined Oct 2009, 408 posts, RR: 0
Posted (4 years 2 months 2 weeks 6 days 6 hours ago) and read 11594 times:

I apologize in advance for the bluntness of the question but after some searches here and on google I havent been able to find anything. I know that the A380 is one of the quietest if not (correct me if Im wrong) the quietest passenger jet. So this led me to the question of whether or not the very technological 787 with its even newer engines could be more quiet and by how much in terms or decibels or just "general" both inside and out.

I really appreciate any help and moderators please feel free to lock the thread after the main point is reached

26 replies: All unread, showing first 25:
 
User currently offlineDecromin From United Kingdom, joined Feb 2008, 80 posts, RR: 0
Reply 1, posted (4 years 2 months 2 weeks 6 days 5 hours ago) and read 11542 times:

Hard to say, as it's not really an apples to apples comparison. In terms of exterior noise, it probably going to be as quiet or quieter than a 380 on takeoff (

User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 2, posted (4 years 2 months 2 weeks 6 days 5 hours ago) and read 11489 times:

Quoting Aeroflot001 (Thread starter):
So this led me to the question of whether or not the very technological 787 with its even newer engines could be more quiet and by how much in terms or decibels or just "general" both inside and out.

For exterior, I would expect the 787 to be quieter. The 787 has much less installed thrust than the A380, from similarly large diameter engines, so it's dumping a lot less energy at comparable shear rates, therefore engine noise should be less. The 787 also has a simpler flap system and less landing gear dragging through the wind, which should especially reduce approach/landing noise beyond the A380.

However, in trade, the 787 has a much thinner fuselage wall, the engines are closer to the fuselage, and the wing is much less massive, so I expect the A380 interior noise to be less than a 787.

Tom.


User currently offlineBMI727 From United States of America, joined Feb 2009, 15778 posts, RR: 27
Reply 3, posted (4 years 2 months 2 weeks 6 days 5 hours ago) and read 11389 times:

Quoting Aeroflot001 (Thread starter):
. I know that the A380 is one of the quietest if not (correct me if Im wrong) the quietest passenger jet

From a passenger perspective I didn't find it any more quiet on the upper deck than the front portion of a 747. From the outside, I found the A380 to be about as quiet as any other modern airliner.

Quoting tdscanuck (Reply 2):
For exterior, I would expect the 787 to be quieter.

The 787 is the quietest airliner I've ever heard, even more so than regional jets. There is very little noise and what there is is basically just the growl or whine from the blades. The exhaust noise is very little and mostly drowned out by the blades.

Quoting tdscanuck (Reply 2):
The 787 also has a simpler flap system and less landing gear dragging through the wind, which should especially reduce approach/landing noise beyond the A380.

The landing gear and spoiler noise on the A380 is considerably blunted on the upper deck, and the flaps were only audible when in transit but didn't really add any more wind noise.



Why do Aerospace Engineering students have to turn things in on time?
User currently offlineDocLightning From United States of America, joined Nov 2005, 19921 posts, RR: 59
Reply 4, posted (4 years 2 months 2 weeks 6 days 3 hours ago) and read 11322 times:

The 787 should produce half the exterior noise of the A380 or less. The engines on the 787 produce slightly less thrust than the A380 engines. And there are half the number.

I have stood directly under the A380 at TGM, which is about 1,000 feet short of the runway at LHR and she was much quieter than an A320.


User currently offlineStitch From United States of America, joined Jul 2005, 31096 posts, RR: 85
Reply 5, posted (4 years 2 months 2 weeks 6 days 2 hours ago) and read 11309 times:
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The A380 is very quiet inside.

Outside, the 787 seems quieter to me on departure and approach than the A380, but the A380 herself is very quiet compared to, say, a 747-400.


User currently offlineastuteman From United Kingdom, joined Jan 2005, 10101 posts, RR: 97
Reply 6, posted (4 years 2 months 2 weeks 5 days 23 hours ago) and read 11225 times:
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Quoting DocLightning (Reply 4):
The engines on the 787 produce slightly less thrust than the A380 engines. And there are half the number.
Quoting DocLightning (Reply 4):
I have stood directly under the A380 at TGM, which is about 1,000 feet short of the runway at LHR and she was much quieter than an A320.

Pretty much a fair summation of the "subjective" declarations on this thread, I'd have thought.

The 787 will be quieter because it has half the engines and less thrust, but the A380 is quieter than an A320   

Back in the engineering world, both aircraft have been aimed at the same departure and arrival classifications.

The A380 beat those classifications soundly.
The 787 might well do also, (and I expect it to) but I've seen nothing yet that says it has.

I'm keen to see a comprehensive 787 ACAP, which should give us a good indication for comparison.

Airbus's documents, as far as I can tell, give the GP7000 a smaller noise footprint on the A380 than the Trent 900

Rgds


User currently offlineTheSonntag From Germany, joined Jun 2005, 3625 posts, RR: 29
Reply 7, posted (4 years 2 months 2 weeks 5 days 18 hours ago) and read 11054 times:

I can tell you the 787 will be quieter than Concorde  

Seriously, it is not fair to compare airliners of different classes. Planes which need higher thrust are also noiser, although the A380 already did a great job with its engines.

A fair comparision is the 787 vs A330 and B767. As far as I know, the 787 is much quieter than those 2.


User currently offlineStitch From United States of America, joined Jul 2005, 31096 posts, RR: 85
Reply 8, posted (4 years 2 months 2 weeks 5 days 14 hours ago) and read 10967 times:
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Quoting astuteman (Reply 6):
The 787 will be quieter because it has half the engines and less thrust, but the A380 is quieter than an A320.      

To be honest, when ZA001 flew directly overhead at about 1000m, her noise was eclipsed moments later by an A320-200 a few klicks higher and to the north of my location.

Considering how quiet the A380 is, I would not disagree with a statement it seemed quieter than an A320, especially on approach. Something about the A320's engines create a very deep and loud "howl" when she's descending. A sound unique to the family.

[Edited 2010-08-02 12:15:07]

User currently offlineA342 From Germany, joined Jul 2005, 4689 posts, RR: 3
Reply 9, posted (4 years 2 months 2 weeks 5 days 13 hours ago) and read 10917 times:

Quoting tdscanuck (Reply 2):
The 787 also has a simpler flap system

Simpler in terms of what? I would have thought that simpler than the A380 is barely possible (single-slotted flaps over nearly the whole length of the trailing edge).



Exceptions confirm the rule.
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 10, posted (4 years 2 months 2 weeks 5 days 10 hours ago) and read 10873 times:

Quoting A342 (Reply 9):
Quoting tdscanuck (Reply 2):
The 787 also has a simpler flap system

Simpler in terms of what? I would have thought that simpler than the A380 is barely possible (single-slotted flaps over nearly the whole length of the trailing edge).

A380 is single-slotted Fowler flap (flaps riding carriages on tracks driven by jackscrews). 787 is single-slotted offset hinge...no tracks, no carriages, no jackscrews.

Tom.


User currently offlineA342 From Germany, joined Jul 2005, 4689 posts, RR: 3
Reply 11, posted (4 years 2 months 2 weeks 4 days 10 hours ago) and read 10608 times:

Quoting tdscanuck (Reply 10):

A380 is single-slotted Fowler flap (flaps riding carriages on tracks driven by jackscrews). 787 is single-slotted offset hinge...no tracks, no carriages, no jackscrews.

Interesting. So the canoe fairings are covering the hinges only?


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And maybe you could briefly list a few other advantages and disadvantages of the system on the 787?


Thanks in advance,
A342



Exceptions confirm the rule.
User currently offlinecpd From Australia, joined Jun 2008, 4879 posts, RR: 37
Reply 12, posted (4 years 2 months 2 weeks 4 days 6 hours ago) and read 10560 times:

Quoting Stitch (Reply 5):
The A380 is very quiet inside.

Outside, the 787 seems quieter to me on departure and approach than the A380, but the A380 herself is very quiet compared to, say, a 747-400.

+1 for that. I see (and hear) A380s every day from Qantas, Singapore Airlines and Emirates - and you really notice the difference between those and a Boeing 747-400. But, the A380-84x (841/842) models are also very distinctive sounding - you can pick them out from any other plane if you listen closely.

Quoting astuteman (Reply 6):
Airbus's documents, as far as I can tell, give the GP7000 a smaller noise footprint on the A380 than the Trent 900

I notice no difference between either of them in the real world. They are both similarly quiet on landing approach and on the same departure.


User currently offlineAeroflot001 From Argentina, joined Oct 2009, 408 posts, RR: 0
Reply 13, posted (4 years 2 months 2 weeks 4 days 5 hours ago) and read 10542 times:

Quoting TheSonntag (Reply 7):
Seriously, it is not fair to compare airliners of different classes. Planes which need higher thrust are also noiser, although the A380 already did a great job with its engines.

A fair comparision is the 787 vs A330 and B767. As far as I know, the 787 is much quieter than those 2.

actually thought to myself as I was posting the thread to begin with that they were 2 very different planes. What had made so interested in the subject though was. After the first couple of vids went on youtube after the first commercial flight there was a big hype on just how quiet it was from the inside. I was interested in knowing if the 787 would go ahead and beat it?
then again I am just as interested to hear a takeoff and landing. I havent had the pleasure of hearing the A380 either as it has yet to visit MIA


User currently offlineA342 From Germany, joined Jul 2005, 4689 posts, RR: 3
Reply 14, posted (4 years 2 months 2 weeks 3 days 23 hours ago) and read 10496 times:

Quoting A342 (Reply 11):
So the canoe fairings are covering the hinges only?

And maybe the actuators, I forgot to add. Having said that, it would be interesting to see the actuating mechanism on these hinge flaps.



Exceptions confirm the rule.
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 15, posted (4 years 2 months 1 week 5 days 1 hour ago) and read 10192 times:

Quoting A342 (Reply 11):
So the canoe fairings are covering the hinges only?

And part of the actuator cranks (the actuator itself appears to be up in the trailing edge).
See slide 18 here:
http://www.kat-net.net/publications/..._katnet_ii_bremen_presentation.pdf

And slide 22 here:
http://www.google.com/url?sa=t&sourc...AFQjCNEtgmU0AWE7P3AR97tAkB3oA8BL4Q

Quoting A342 (Reply 11):
And maybe you could briefly list a few other advantages and disadvantages of the system on the 787?

The two presentations above cover a lot of it...better cruise drag, satisfactory takeoff and landing performance, less noise, simpler mechanism. Disadvantage, I assume, is not as much performance as you get from something like a triple-slotted Fowler flap (e.g. 727), but that's only a disadvantage if you actually need that much performance. I think the tacit claim here is that the system performs well enough to do the mission but takes less parts/money/noise/complexity to do it.

Tom.


User currently offlineBoeing1970 From , joined Dec 1969, posts, RR:
Reply 16, posted (4 years 2 months 1 week 4 days 11 hours ago) and read 10059 times:

Quoting Aeroflot001 (Thread starter):
I apologize in advance for the bluntness of the question but after some searches here and on google I havent been able to find anything. I know that the A380 is one of the quietest if not (correct me if Im wrong) the quietest passenger jet. So this led me to the question of whether or not the very technological 787 with its even newer engines could be more quiet and by how much in terms or decibels or just "general" both inside and out.

I really appreciate any help and moderators please feel free to lock the thread after the main point is reached

If you are talking about approach and departure noise around the airport, then yes. It will be significiantly quieter.


User currently offlineViscount724 From Switzerland, joined Oct 2006, 25626 posts, RR: 22
Reply 17, posted (4 years 2 months 1 week 4 days 7 hours ago) and read 10016 times:

Quoting DocLightning (Reply 4):
The 787 should produce half the exterior noise of the A380 or less. The engines on the 787 produce slightly less thrust than the A380 engines. And there are half the number.

It frequently doesn't work that way. Some earlier twin-engine aircraft were much noiser than many far larger aircraft with more engines. I always found the BAC-111 and Hawker-Siddeley Trident and their very loud R-R Spey engines, to be as loud as much larger 4-engine types of similar vintage like 707s and DC-8s. Even some much smaller types using the Spey like the Fokker F-28 and early Gulfstream bizjets were very loud.


User currently offlineAeroflot001 From Argentina, joined Oct 2009, 408 posts, RR: 0
Reply 18, posted (4 years 2 months 1 week 4 days 6 hours ago) and read 10004 times:

Quoting Boeing1970 (Reply 16):

If you are talking about approach and departure noise around the airport, then yes. It will be significiantly quieter.

To be honest I was more interested in the interior noise. I was really hoping the 787 would destroy the A380 in terms of cabin interior noise  


User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 19, posted (4 years 2 months 1 week 4 days 6 hours ago) and read 10000 times:

Quoting Aeroflot001 (Reply 18):
I was really hoping the 787 would destroy the A380 in terms of cabin interior noise

I really doubt that's the case...if they're comparable, I'd be really impressed, because the A380 has so many innate design advantages vis a vis interior noise. I'm not sure what it would take for the 787 to "destroy" the A380 in terms of interior noise, but I'm pretty sure it's not compatible with the efficiency goals of the 787.

Tom.


User currently offlineKPDX From United States of America, joined Dec 2005, 2770 posts, RR: 2
Reply 20, posted (4 years 2 months 1 week 4 days 6 hours ago) and read 9999 times:

Am I the only one that likes engine noise? A cabin that is so quiet that I can't (or just barely can) hear the engines would make me slightly uncomfortable. Engine noise gives me assurance and is white noise for me and many others.


View my aviation videos on Youtube by searching for zildjiandrummr12
User currently offlineBeakerLTN From United Kingdom, joined Jul 2009, 297 posts, RR: 0
Reply 21, posted (4 years 2 months 1 week 4 days 3 hours ago) and read 9964 times:

Quoting KPDX (Reply 20):
Am I the only one that likes engine noise?

I'm half with you. As someone who thinks one of the greatest noises in aviation was a KC-135 (with the old engines) taking off, I love noise... but in the cabin, even the 777 during cruise is too loud for my wife (the moaning that she can't sleep is louder though to be honest)

What I'd love is a loud roar on take off but a silent cruise... and I know that's all but impossible! (legally nowadays and technically!)

Sort of on subject, but I've tried to look this up but never found it.. Does anyone kow the location of table that shows cabin noise for each aircraft type?



300/319/320/321/330/732/733/734/73G/738/744/772/77W/146/EMB135/EMB145
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17068 posts, RR: 66
Reply 22, posted (4 years 2 months 1 week 4 days 1 hour ago) and read 9941 times:

Quoting tdscanuck (Reply 19):
I'm not sure what it would take for the 787 to "destroy" the A380 in terms of interior noise,

A pair of heat-seeking missiles comes to mind.   



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinetrauha From Finland, joined Dec 2010, 5 posts, RR: 0
Reply 23, posted (3 months 3 weeks 16 hours ago) and read 2684 times:

Get a decibel meter. I measure noise levels on every flight I take with a dB meter.
A lot of seats are subject to amounts of noise that would be illegal in a Scandinavian work place for instance.


User currently offlineTheSonntag From Germany, joined Jun 2005, 3625 posts, RR: 29
Reply 24, posted (3 months 3 weeks 1 hour ago) and read 2405 times:

Now where did you find this thread  

25 dynamicsguy : Almost every time someone resurrects one of these long-silent Tech Ops threads I get tricked into thinking that Tdscanuck has returned.
26 aircellist : Same here. I was all happy to see him again…
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