B727LVR
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737 Quiet Wing Mod

Fri Apr 12, 2013 5:37 pm

I have recently heard some friends of mine talking about the "Quiet Wing" modification for 737-400's, vice using a winglet mod. I don't know know of any approved winglet mods for a -400, but I could be wrong. Do any of you know anything about the quiet wing? Good, bad, or indifferent. I would love to hear from those that have the -400 experience to see if this application would be good for any of the -400 variants (pax/combi/freighter). I know my pilot friends are a little skeptical, about it. Their biggest argument point is that if it was such a good thing, operators like Alaska, US Airways, or Southwest would be all over it, but to their knowledge each of them are trying to suck the flaps up in tighter to get the out of the air stream vice putting them out further into it. Would love to see what your thoughts and comments are on this.

Here is a link to the mod in question:

http://quietwing.com/performance-systems/
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Max Q
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RE: 737 Quiet Wing Mod

Fri Apr 12, 2013 6:57 pm

Looks like the opposite to me.


The article implies the flaps will be extended slightly more in cruise.


Don't see how that saves fuel but i'm no engineer..
The best contribution to safety is a competent Pilot.
 
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tb727
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RE: 737 Quiet Wing Mod

Fri Apr 12, 2013 8:20 pm

We are currently putting a couple 727's through the program, while not a 734, I also am wondering really how much difference it is going to make and if it is so good, why don't they all have it?
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Starlionblue
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RE: 737 Quiet Wing Mod

Sat Apr 13, 2013 12:17 am

Quoting Max Q (Reply 1):
The article implies the flaps will be extended slightly more in cruise.

Don't see how that saves fuel but i'm no engineer..

There were 727 crews who would extend the flaps 2 degrees since this apparently increased lift without increasing drag. They had the pull a CB so the slats wouldn't extend. Completely unauthorized of course.

This probably led to the incident with TWA 841 (the crew denied it). http://en.wikipedia.org/wiki/TWA_Flight_841_(1979)
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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tb727
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RE: 737 Quiet Wing Mod

Sat Apr 13, 2013 12:37 am

Quoting Starlionblue (Reply 3):
There were 727 crews who would extend the flaps 2 degrees since this apparently increased lift without increasing drag. They had the pull a CB so the slats wouldn't extend. Completely unauthorized of course.

When the flaps go to 2 at that speed it apparently pitches the nose down just a little for less drag I guess that's why they did it. I'm still waiting for the differences chapter to look at and see what it does exactly.
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mercure1
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RE: 737 Quiet Wing Mod

Sat Apr 13, 2013 1:42 am

works similar to the Boeing 777 PIP. Drooped trailing edge devices to increase lift, for very minimal additional drag. Creates better L/D compared to clean wing, etc. http://www.boeing.com/commercial/aer...03_09/pdfs/AERO_Q309_article02.pdf
 
FlyMKG
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RE: 737 Quiet Wing Mod

Sat Apr 13, 2013 3:59 am

We have one remaining QuietWing 722 in our fleet. It has both the flap droop and the winglets. The inboard flap droop makes the plane slightly more unstable than a Boeing wing plane. This is most noticable in cruise flight. The winglets seem to have no apparent fuel savings. They do however, make it a bit more challenging in a crosswing landing since there is more surface for the wind to hit.

In the 727 circle the QuietWing was the cheapest and least popular of the three hush kit options. (The other two being FedEx and Raisbeck.) I believe this was due to most thinking it messed with the "perfect" Boeing wing too much. It also has a severe performance hit on takeoff under most conditions. Very counterproductive.

With all that being said, in our fleet, the QuietWing airplane is far and away the easiest to fly compared to our Valsan planes. Everything happens at a much more controlled pace. It is a more civilized bird.

FlyMKG
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Max Q
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RE: 737 Quiet Wing Mod

Sat Apr 13, 2013 6:02 am

Quoting Starlionblue (Reply 3):
There were 727 crews who would extend the flaps 2 degrees since this apparently increased lift without increasing drag.

Well that's nonsense.


Flaps 2 gives you extension of Slats 2,3,6 and 7 and certainly increases drag as will sticking anything out into the airflow.



Whatever that TWA crew did that night, whether inadvertent or deliberate it was not going to improve that Aircraft's performance.
The best contribution to safety is a competent Pilot.
 
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Starlionblue
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RE: 737 Quiet Wing Mod

Sat Apr 13, 2013 6:39 am

Quoting FlyMKG (Reply 6):
The winglets seem to have no apparent fuel savings.

I think the idea is that the winglets increase climb performance, thus getting the aircraft out of range of NIMBY ears more quickly.

Quoting Max Q (Reply 7):
Quoting Starlionblue (Reply 3):
There were 727 crews who would extend the flaps 2 degrees since this apparently increased lift without increasing drag.

Well that's nonsense.

Agreed that it would probably not improve performance, but the crew seemed to think it would.

See the first point on page 32 of the NTSB report: "There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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Starlionblue
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RE: 737 Quiet Wing Mod

Sat Apr 13, 2013 6:40 am

Man the posting engine is giving errors. Here's the verbiage:

While cruising at mach 0.816 and 39,000 feet pressure altitude and wuth the autopilot controlling the aircraft, an apptempt was made to extend 2deg of trailing edge flaps independently of the leading edge slats, probably in an effort to improve aircraft performance.

Source is the NTSB report which I can't link because it is breaking the post...
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo

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