Fly2HMO
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Joined: Sat Jan 24, 2004 12:14 pm

Do Airlines Pick Interior Soundproofing Levels?

Fri Jan 23, 2009 5:59 pm

Quick question I've been meaning to ask for a while: Can an airline pick how "quiet" their planes are?

This question popped up years ago when I had my first flight in a 73G, with WN. I thought it was a nice bird, except that I found it to be more noisy than Airbus narrowbodies, so I was kind of disappointed. My best friend who is a pilot as well noticed this too. Not long after I went on several 73G flights with both CO and AM and I thought their planes were much quieter than WN's. All flights had pretty high pax loads, were cruising between FL380/400 and averaged about 2hrs of flight time, so they were all in very similar conditions. My best friend accompanied me on many of these flights as well and he noticed the difference too.

So my theory is: I figured southwest, having a fetish for ultimate efficiency and lighter weight, maybe sacrificed some sound proofing material/fixtures. AM and CO, being concerned a bit more with pax comfort, did not.

So, my fellow a.nuts: was I hearing (or not hearing) things? Was it my imagination? Or is there some truth in my theory?   

Cheers   

[Edited 2009-01-23 10:00:33]
 
QANTAS747-438
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RE: Do Airlines Pick Interior Soundproofing Levels?

Sat Jan 24, 2009 3:37 am

One question: Where did you happen to sit on the WN flight versus the CO, AM, and Airbus flights?
My posts/replies are strictly my opinion and not that of any company, organization, or Southwest Airlines.
 
pianos101
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RE: Do Airlines Pick Interior Soundproofing Levels?

Sat Jan 24, 2009 4:05 am

I wanted to see what anyone else would say before chiming in...

QANATS' point it a good one: the most obvious answer to your question is where you sat on the plane, and the type of engines that were on each particular aircraft.

Beyond that, insulation (between the cabin sidewall panels and the skin) is NOT a customer option. The insulation blankets there are standard equipment. That said, I don't see a reason why an airline can't do something different within the confines of systems and structure that are in that are. I wouldn't see why they'd want to though; any configuration that's different than the factory configuration only adds cost.

So to sum up, I'm almost positive that airlines do not "pick" soundproofing levels; that is not a customer option from the factory.
 
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HAWK21M
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Joined: Fri Jan 05, 2001 10:05 pm

RE: Do Airlines Pick Interior Soundproofing Levels?

Sat Jan 24, 2009 7:33 am

Tampering the Insulation blankets would lower the in cruise temperature significantly.On a Pax aircraft it would not be advisable.On freighters though its done for the Main deck areas & contributes to significant weight loss,but it can get very cold in cruise.
The blankets are retained at Flight deck areas.

About the comparism of sound levels,one would need to be seated in the same place on all aircraft,operated by similiar type powerplant & running at exactly same speed to make an accurate judgement,which is difficult to perform.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Fly2HMO
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Joined: Sat Jan 24, 2004 12:14 pm

RE: Do Airlines Pick Interior Soundproofing Levels?

Sat Jan 24, 2009 11:50 pm



Quoting QANTAS747-438 (Reply 1):
One question: Where did you happen to sit on the WN flight versus the CO, AM, and Airbus flights?

3/4 of the time it was behind the overwing exits (on the other airlines as well), usually in rows by the wing's trailing edge. I know they're more quiet towards the front as with most planes so I did take that into account. It just gave me the impression that the rumble from the engine's exhaust seemed to be more noticeable on WN's planes, for whatever reason.
 
QANTAS747-438
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RE: Do Airlines Pick Interior Soundproofing Levels?

Thu Jan 29, 2009 5:09 am



Quoting FLY2HMO (Reply 4):
Quoting QANTAS747-438 (Reply 1):
One question: Where did you happen to sit on the WN flight versus the CO, AM, and Airbus flights?

3/4 of the time it was behind the overwing exits (on the other airlines as well), usually in rows by the wing's trailing edge. I know they're more quiet towards the front as with most planes so I did take that into account. It just gave me the impression that the rumble from the engine's exhaust seemed to be more noticeable on WN's planes, for whatever reason.

I think there are too many variables to give a solid answer. For WN, you could have flown on a new -700 like N900WN or you could have flown on our oldest -300, N300SW, which sounds like a rocket from the back row. If you compare the -300 to the Airbus, then the Airbus will be much quiter.

Weather also comes into play. Descending into SFO fog or clouds can generate some added noise, but I remember landing in MCO on a clear day and I could have sworn we were on a glider... dead silent.

SO... to give you something, no, airliners do not add extra or less insulation.
My posts/replies are strictly my opinion and not that of any company, organization, or Southwest Airlines.
 
chapavaeaa
Posts: 35
Joined: Wed Aug 13, 2008 4:35 pm

RE: Do Airlines Pick Interior Soundproofing Levels?

Wed Feb 04, 2009 3:45 am

Years ago I was involved in a project to sound deaden a turboprop aircraft. We spent the better part of a year investigating two different methods of quieting the cabin. One was an "Active Noise" generator. Basically a bunch of microphones and speakers working together to generate a frequency that would cancel out/reduce the noise level on the aircraft. It worked pretty well on the aircraft as I recall.

The other method was a "Tuned Damper" method. This was a bunch of tuned weights on rubber mounts that were placed in very specific locations in the cabin and were designed to absorb a great deal of the fuselage vibration. It was never installed but appeared that it would work quite well.

The Tuned Damper was slightly heavier (not by much) than the Active Noise system. The Active Noise was going to require regular maintenance but was a slightly less initial cost.

All in all it was a fun project.
 
Viscount724
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RE: Do Airlines Pick Interior Soundproofing Levels?

Wed Feb 04, 2009 5:05 am



Quoting Chapavaeaa (Reply 6):
Years ago I was involved in a project to sound deaden a turboprop aircraft. We spent the better part of a year investigating two different methods of quieting the cabin. One was an "Active Noise" generator. Basically a bunch of microphones and speakers working together to generate a frequency that would cancel out/reduce the noise level on the aircraft. It worked pretty well on the aircraft as I recall.

The Saab 2000 has that type of active noise reduction system. You can see the speakers in the cabin wall panels every couple of seat rows.

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