UAL747
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Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 11:54 am



SEATTLE, Nov. 20, 2001 -- Boeing Commercial Airplanes and Rolls-Royce Aero Engines have completed a noise reduction flight test program that promises to make quiet jets even quieter.

Known as the Quiet Technology Demonstrator (QTD), a Rolls Royce Trent 800 engine was modified with a package of noise reduction technologies developed collaboratively by the two aerospace companies. Using a 777-200ER, the three week flight-test demonstrated noise levels significantly below those of a standard 777, which is known as one of the quietest airplanes in service today. Takeoff jet exhaust noise was reduced by up to four decibels and inlet fan noise was reduced by up to 13 decibels.

Engineers used saw-tooth-shaped aerodynamic devices at the rear of the nacelle and on the exhaust nozzle to control the mixing of the hot jet exhaust, the bypass stream and the ambient air. The shape of the devices was determined by computational fluid dynamics modeling and verified in wind tunnel tests using scale models.

Fan noise also was reduced with extensive acoustic improvements to the redesigned engine nacelle inlet. A new technology called Amax (area maximization) increased by 30 percent the area of acoustic treatment in the inlet casing. A new lining design was used that reduces objectionable "buzz saw" noise passengers often hear during takeoff and climb.

The flight tests, conducted at Boeing's Glasgow, Mont., airfield, verified the computer and laboratory results. Some 200 microphones were placed on the ground along the flight path, and 100 microphones were affixed to the 777. Teamed with computers, the microphones became an "acoustic camera" that accurately and dynamically pinpointed high-frequency noise sources on the airplane as it took off, flew the flight test pattern and landed again. This ground noise monitoring capability was made possible by NASA sponsorship.

Although the purpose of the QTD program was to reduce noise heard on the ground, levels within the cabin -- equally important to the airlines - also were analyzed. Nearly 100 microphones placed along the entire length of the cabin registered a reduction of forward cabin buzz-saw noise by seven decibels.

The culmination of years of work, these successful tests mark one of the final stages before QTD noise reduction technology is implemented in service. Combined with airframe noise reduction and engine redesign efforts being pursued separately, the new technologies can be incorporated on a new airplane program or as a retrofit to airplanes in service.


Looks kinda strange if you ask me.

UAL747
"Bangkok Tower, United 890 Heavy. Bangkok Tower, United 890 Heavy.....Okay, fine, we'll just turn 190 and Visual Our Way
 
UAL747
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 11:58 am

"Bangkok Tower, United 890 Heavy. Bangkok Tower, United 890 Heavy.....Okay, fine, we'll just turn 190 and Visual Our Way
 
hkgspotter1
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 12:08 pm

It looks.....eerh nice but does it work ??. 777 dont even make much noise.

Also which aircraft is this being tested on ??. It can be the test 777 at it's B-HNL with CX.
 
dynkrisolo
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 12:12 pm

I believe it is a B777 to be delivered to AA.
 
vafi88
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 12:15 pm

That looks cool! it has the squigly things on it!
I'd like to elect a president that has a Higher IQ than a retarted ant.
 
ba777-236
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 12:23 pm

Any idea on why Boeing chose the B777 (one of it's quietest planes) for this test?

Ba777-236
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hkgspotter1
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 12:28 pm

Thats what I mean, they dont make any noise. I see the CO 772 depart HKG for NYC and that is almost silent !!
 
Max Q
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 12:53 pm

This modification could be a big advantage for airlines
seeking departure and arrival times at unpopular hours at noise sensitive airports.

Not to mention the good PR resulting from being more
'environmentally friendly'

And one day stage 4 noise limits will be a reality.
The best contribution to safety is a competent Pilot.
 
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RayChuang
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 1:23 pm

My guess is that this new engine nacelle breakthrough is just the thing to make new airplanes compliant with the toughest noise-emission standard for airplanes in the world--LHR's so-called QC2 standard.

Rolls-Royce might apply this to the nacelle of the Trent 900's that will be installed on the A380-800, that's to be sure.
 
BH346
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 1:27 pm

I hear the 777 is a bit noisy. Is this true?
Northwest Airlines - Some People Just Know How to Fly
 
Mr.BA
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 1:38 pm

I find the B777 is a bit noiser in the inside but it is really quiet on the outside.

alvin
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AWspicious
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 2:58 pm

Reminds me of a cookie cutter  Smile/happy/getting dizzy
I assume they used the 777 as a test platform because it represents the cutting edge of civil aviation technology. (pardon the pun) They took one their most advanced engines and tried to make it even better. Push the envelope, if you will.
Perhaps, they felt it was better to demonstrate their ability to improve on technology that was designed for tomorrow than on technology that's almost past it's time.
Nevermind political correctness - Envision using your turn signals!
 
FLY777UAL
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 5:53 pm

It'll be great, especially with cutting down on the noise forward of door 2! It's horrible up there w/o headsets on!

F L Y 7 7 7 U A L
 
hkg_clk
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RE: Rolls Royce Introduces New Quiet 777 Engine

Fri Dec 21, 2001 6:33 pm

That saw-tooth shape nacelle looks cool!! I guess they're testing it on the 777 as it has the longest production cycle remaining and will therefore have to comply with many new regulations in the future.

I thought some manufacturers were going to use noise cancellation technology at one point? Did it not work?
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