Cockpit noise
Thread Starter
Joined: Aug 2010
Posts: 79
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From: between FL0-350
Cockpit noise
Hey guys!
I just have a question that had been haunting my mind last couple of weeks!
All boeing 737 NGs are fited with 10 tiny Vortex Generators near the front windshield and on the nose (not the aft VGs!). And Boeing says it reduces cockpit noise.
Another friend of mine said, it is to energize the airflow which may disturbe by the gap of the radome hing area.
Will anybody know what is the story behind this 10 VGs? and technically how it will reduce the cockpit "noise" ?. I appriciate a very discriptive one
Thank a lot!
Code0
I just have a question that had been haunting my mind last couple of weeks!
All boeing 737 NGs are fited with 10 tiny Vortex Generators near the front windshield and on the nose (not the aft VGs!). And Boeing says it reduces cockpit noise.
Another friend of mine said, it is to energize the airflow which may disturbe by the gap of the radome hing area.
Will anybody know what is the story behind this 10 VGs? and technically how it will reduce the cockpit "noise" ?. I appriciate a very discriptive one
Thank a lot!
Code0
Joined: Jun 2010
Posts: 304
Likes: 0
From: Brisbane, Australia
I also was advised those vortex generators immediately ahead of the #1 windshields was for noise reduction.
I assumed the parked wiper arms/blades were the main cause in that area.
Also, the deletion of the eye-brow windows happened at the same time in the production line.
EW73
I assumed the parked wiper arms/blades were the main cause in that area.
Also, the deletion of the eye-brow windows happened at the same time in the production line.
EW73
Joined: Feb 2008
Posts: 96
Likes: 1
From: h&h
It's said they are installed for noise reduction. However not all 737NG's are fitted with the vortex generators. I believe it only makes a small difference, the 737 cockpit is just very noisy...
I don't exactly know the technicalities behind it, but I assume that the VG's guide the airflow away from the wipers and streamlining the airflow, creating less parasite drag and thus less noise.
I don't exactly know the technicalities behind it, but I assume that the VG's guide the airflow away from the wipers and streamlining the airflow, creating less parasite drag and thus less noise.
Joined: Jul 1999
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From: 58-33N. 00-18W. Peterborough UK
Thread Starter
Joined: Aug 2010
Posts: 79
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From: between FL0-350
Thanks guys. I know it's kind of hard to understand exactly.
I don't get the point those VGs could reduce the noise of airflow hit the shield at the cruise velocity.
and also those VGs will energize the airflow, which makes the velocity further at a high number. Hense it will hit the shield at a more higher speed!.
I didn't know not all NGs are not fitted with these VGs, thanks for you info.
anyhow if really it reduces cockpit noise, why other airliners do not adopt that? is it Beoing patient?
I am still struggling to find the answers! but always end up with only with questions!
Thank guys
cheers!
Code0
I don't get the point those VGs could reduce the noise of airflow hit the shield at the cruise velocity.
and also those VGs will energize the airflow, which makes the velocity further at a high number. Hense it will hit the shield at a more higher speed!.
I didn't know not all NGs are not fitted with these VGs, thanks for you info.
anyhow if really it reduces cockpit noise, why other airliners do not adopt that? is it Beoing patient?
I am still struggling to find the answers! but always end up with only with questions!
Thank guys
cheers!
Code0
Joined: Jul 2010
Posts: 70
Likes: 0
From: shanghai
3dB!!!
my hearing has been deteriorating since my first flight~
5 years flying(riding on the right) cause my left ear hearing is worse than my right side one.
because the right ear is covered by the headset, the left ear is exposed to the open cockpit air( for the crew communication and aural warning).
does anyone has the same situation as me ???
my hearing has been deteriorating since my first flight~
5 years flying(riding on the right) cause my left ear hearing is worse than my right side one.
because the right ear is covered by the headset, the left ear is exposed to the open cockpit air( for the crew communication and aural warning).
does anyone has the same situation as me ???
Joined: Jul 1999
Posts: 3,040
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From: 58-33N. 00-18W. Peterborough UK
bearfoil, just for you. If nothing else you'll get to see a line drawing of an Armstrong Whitworth Argosy.
Considerations about forward fuselage design
Considerations about forward fuselage design
Joined: Mar 2001
Posts: 4,563
Likes: 35
From: I wouldn't know.
Cant say the insect deflecting works well either. Both effects are rather small, but noticeable if you fly both types of NG (with and without the VGs).
As for your ear problems, i would suggest a good filter plug and/or a noise cancelling headset worn on both ears.
As for your ear problems, i would suggest a good filter plug and/or a noise cancelling headset worn on both ears.
Joined: Aug 2009
Aviation Qualifications: ATPL
Posts: 616
Likes: 57
From: GPS L INVALID
I find the difference between 9 year old NGs and recently delivered models is pretty significant in terms of noise level. The VGs do their part especially during high speed flight while the redesigned fresh air ducting takes away a lot of the white background noise. Amazing how some old planes become almost silent with the recirculation fans off...
Joined: Jul 2010
Posts: 70
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From: shanghai
one of my college sometimes doing this (turn off the recirculation fan during flight which i never done)
he said it`s quite quiet~
and pull out one of the CB of the standby attitude indicator drum vibraration. it also reduce the cockpit noise
i agree with the noise reduction, but i will never do this!
he said it`s quite quiet~
and pull out one of the CB of the standby attitude indicator drum vibraration. it also reduce the cockpit noise
i agree with the noise reduction, but i will never do this!
Joined: Mar 2001
Posts: 4,563
Likes: 35
From: I wouldn't know.
On the -800 we usually have the nr. 1 recirc fan off below FL100, on the -700 the only one, only downside is slightly higher fuel burn. Makes for a much less noisy cockpit environment. Thank god the good ol' standby altimeter vibrator is not an issue anymore with the ISFD, that was kinda annoying and some CPTs pulled the CB for that which i never really liked as there is a reason for the vibrator, however noisy it is.
Thread Starter
Joined: Aug 2010
Posts: 79
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From: between FL0-350
After 2 weeks I found the answer for this.
VGs over the nose of 737NGs are to reduce the cockpit noise. These VGs are totally different to the VGs you find near control surfaces.
these cockpit noise reduction VGs are blunt bodies. they blick the airflow so it reduces the local velocity near the windshield, hense the airflow hit the no.1 windshileds is slowed.
it is obvious that these 10 VGs produce some sort of drag but I guess it is neglegible.
Anyhow I havent come across anyother aircraft fixed with these kind of VGs for voice.
cheers!
code0
VGs over the nose of 737NGs are to reduce the cockpit noise. These VGs are totally different to the VGs you find near control surfaces.
these cockpit noise reduction VGs are blunt bodies. they blick the airflow so it reduces the local velocity near the windshield, hense the airflow hit the no.1 windshileds is slowed.
it is obvious that these 10 VGs produce some sort of drag but I guess it is neglegible.
Anyhow I havent come across anyother aircraft fixed with these kind of VGs for voice.
cheers!
code0
