LH707330
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P&W Vacuum Cleaner Noise At Idle

Fri Aug 31, 2012 11:18 pm

Forgive me if this has been covered before, but what causes the vacuum cleaner noise in P&W turbofans? I was at Sea-Tac yesterday, and noticed a DL 757-200 (2037), Condor 767-300ER (4060), and KL 744F (4060) all make it. I've heard UA 772 (4090) make this noise in the past as well, and I have not heard it from RR or GE engines.
 
N243NW
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RE: P&W Vacuum Cleaner Noise At Idle

Sat Sep 01, 2012 4:44 am

If it's what I think you're talking about (a constant resonant "woo" sound), then the CF6 tends to do it as well.

Is it the sound that you can hear starting at :30 in this video? http://www.youtube.com/watch?v=oBaYs2NjCQU

Sounds like combustor tone to me.
B-52s don't take off. They scare the ground away.
 
my235
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RE: P&W Vacuum Cleaner Noise At Idle

Sat Sep 01, 2012 5:17 am

I hear it all the time when the A300F use break-away thrust after being pushed back. They have P&W's. Love it!
 
tdscanuck
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RE: P&W Vacuum Cleaner Noise At Idle

Sat Sep 01, 2012 2:26 pm

Quoting N243NW (Reply 1):
Sounds like combustor tone to me.

Agreed. This isn't limited to P&W...the Trent1000 has an epic bass combustor tone during startup when it's cold outside.

Tom.
 
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Aaron747
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RE: P&W Vacuum Cleaner Noise At Idle

Sat Sep 01, 2012 4:01 pm

A video I took a few years back that dramatically illustrates the point whenever this thread topic comes up  http://www.youtube.com/watch?v=UuLMJXemd-Y
If you need someone to blame / throw a rock in the air / you'll hit someone guilty
 
9VSIO
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RE: P&W Vacuum Cleaner Noise At Idle

Sat Sep 01, 2012 4:55 pm

When I saw the title of this thread, I thought that Pratt & Whitney had made a vacuum cleaner! Imagine my disappointment...
Me: (Lining up on final) I shall now select an aiming point. || Instructor: Well, I hope it's the runway...
 
N243NW
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RE: P&W Vacuum Cleaner Noise At Idle

Sat Sep 01, 2012 9:45 pm

Quoting tdscanuck (Reply 3):
the Trent1000 has an epic bass combustor tone during startup when it's cold outside.

So does the GE90-110/115B at pretty much any temperature. You can often hear it across the airport, even through terminal windows!
B-52s don't take off. They scare the ground away.
 
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longhauler
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RE: P&W Vacuum Cleaner Noise At Idle

Sun Sep 02, 2012 12:55 am

The DC-8-62/63 also make the same noise. I always loved it.

It starts at 1:10 in this video:

http://www.youtube.com/watch?v=lRaXQUXOUJA
Just because I stopped arguing, doesn't mean I think you are right. It just means I gave up!
 
planejamie
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RE: P&W Vacuum Cleaner Noise At Idle

Sun Sep 02, 2012 10:08 am

I think the RR Trent 700 and 800 has a similar "woo"-ing sound when above idle (about 30-50% N1) you notice it when they spool up for take off or when giving a little bit more power into taxiing. I never knew the PWs made that noise!

Quoting 9VSIO (Reply 5):
When I saw the title of this thread, I thought that Pratt & Whitney had made a vacuum cleaner! Imagine my disappointment...

Would be awesome, it could be shaped like a jet engine

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