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stephen88
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What are these small thin edges on the Boeing 737-800 wing?

Fri Aug 12, 2016 5:07 pm

I've noticed that they're not on all 737-800 wings, I've only seen them on Qantas and Garuda Indonesia aircraft.

Image
 
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Polot
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Re: What are these small thin edges on the Boeing 737-800 wing?

Fri Aug 12, 2016 5:15 pm

Those are vortex generators. They, as the name implies, generate vortexes to improve the aerodynamics and aircraft's efficiency/noise levels. Pretty popular with Boeing, Airbus generally avoids using them.

Sometimes additional ones may have been added in performance improvement packages and whatnot over time, which is why not every aircraft (of a single type) has the same number in the same place.
 
citationjet
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Re: What are these small thin edges on the Boeing 737-800 wing?

Fri Aug 12, 2016 9:59 pm

American has them on their 737-800s. <photoid:1876996> I don't know how to post photos in the new website......
 
ooslc
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Re: What are these small thin edges on the Boeing 737-800 wing?

Fri Aug 12, 2016 10:18 pm

AS has them pretty much across the entire span of the wing on the 734 and only part of the wing on the rest of the fleet.
 
c680
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Re: What are these small thin edges on the Boeing 737-800 wing?

Fri Aug 12, 2016 10:37 pm

Vortex Generators - they delay flow separation and improve low speed performance. Small drag penalty for a reduction in stall speed or improved low speed control surface performance.

As aerodynamic designs have improved over the years, these devices are seen less and less, thus more of them on older planes. In many cases, they are added to an aircraft by the manufacture after the plane was designed as a way to fix a problem or improve performance.
 
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DocLightning
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Re: What are these small thin edges on the Boeing 737-800 wing?

Fri Aug 12, 2016 11:11 pm

c680 wrote:
As aerodynamic designs have improved over the years, these devices are seen less and less, thus more of them on older planes. In many cases, they are added to an aircraft by the manufacture after the plane was designed as a way to fix a problem or improve performance.


Every Boeing except the 747 has them, including the 787.

First, they are not airline-dependent, they are a standard part of the wing of every 737NG. Second, they are not a way to "fix a problem" any more than flaps are. They are one of many possible solutions to handling certain aerodynamic situations.

At high angles of attack, the flow may start to separate right behind the position of the VGs. The VGs serve to energize the boundary layer and keep the flow attached to the wing, preventing the stall. At cruise, the VGs are more or less aligned with the local airflow and produce minimal drag.

Airbus uses envelope protection on their aircraft and so they do not use the VGs on their wings.
 
c680
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Re: What are these small thin edges on the Boeing 737-800 wing?

Sat Aug 13, 2016 3:24 am

DocLightning wrote:
Every Boeing except the 747 has them, including the 787.


I did not say they had disappeared - I said you see less of them with modern wings than in the past

DocLightning wrote:
First, they are not airline-dependent, they are a standard part of the wing of every 737NG.

Where did I say they were airline dependent? I said they are installed by the manufacture.

DocLightning wrote:
Second, they are not a way to "fix a problem" any more than flaps are. They are one of many possible solutions to handling certain aerodynamic situations.
Actually, they do fix problems that were not anticipated, and later discovered during flight testing. We had a boundary layer separation issue on the cruciform tail of our CE-680, (which was a low serial number) that was solved with a couple of VGs on each side. That became a standard feature of the airframe, and a part of the limitations; however I do agree with you that they are a fairly standard solution for certain aerodynamic situations.

DocLightning wrote:
Airbus uses envelope protection on their aircraft and so they do not use the VGs on their wings.
Oh really? Better tell Lufthansa to take those VGs off their A320 wings...
http://aviationweek.com/blog/lufthansas ... eer-closer
 
Viscount724
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Re: What are these small thin edges on the Boeing 737-800 wing?

Sat Aug 13, 2016 3:44 am

c680 wrote:
DocLightning wrote:
Airbus uses envelope protection on their aircraft and so they do not use the VGs on their wings.
Oh really? Better tell Lufthansa to take those VGs off their A320 wings...
http://aviationweek.com/blog/lufthansas ... eer-closer


That's not the same thing. That small Airbus A320 modification was only to reduce the annoying noise from overflying aircraft caused by air passing over the vent hole in the bottom of the wing.

If memory correct, the only Airbus aircraft with the Boeing-type of vortex generators on the upper wing surface, on all Boeing models since the 707 (except the 747), was the early-model A300.
 
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DocLightning
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Re: What are these small thin edges on the Boeing 737-800 wing?

Sat Aug 13, 2016 3:58 am

c680 wrote:

I did not say they had disappeared - I said you see less of them with modern wings than in the past


Fewer VGs per aircraft, yes. But I do not think Boeing will ever stop using them on their subsonic airliners.
Where did I say they were airline dependent? I said they are installed by the manufacture.


You did not, but someone else.
Actually, they do fix problems that were not anticipated, and later discovered during flight testing.


Not at Boeing, at least on the 737-NG wing, (which is the topic of this thread) the 777 wing, or the 787 wing. Those VGs were planned from the outset. Not sure if the 767 wing (which has its VGs in an irregular arrangement) was patched up after flight testing. Boeing has had to make other modifications based on flight testing results. Recently, the 747-8 had an unexpected aerodynamic interaction between the inboard flaps and the outer MLG bay doors that caused flap buffet at full flaps. The gear door was modified and a vortilon was added to the inboard flap.

DocLightning wrote:
Airbus uses envelope protection on their aircraft and so they do not use the VGs on their wings.
Oh really? Better tell Lufthansa to take those VGs off their A320 wings...
http://aviationweek.com/blog/lufthansas ... eer-closer


Those VGs are a recent addition and they were --in contrast to the upper-surface VGs on the 737-- intended to fix a problem. That problem is the noise made by that vent. They do not have anything significant to do with the flying characteristics or control of the aircraft.

It seems like you want to pick an argument with me. I don't know why.
 
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usxguy
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Re: What are these small thin edges on the Boeing 737-800 wing?

Sat Aug 13, 2016 4:37 am

interesting thread.. i guess that explains why I've seen rows of VG's on flaps..

Image
 
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cathay747
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Re: What are these small thin edges on the Boeing 737-800 wing?

Sat Aug 13, 2016 12:18 pm

It should be noted that the 727 had them on the vertical fin, not on the wing.
 
VC10er
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Re: What are these small thin edges on the Boeing 737-800 wing?

Sat Aug 13, 2016 12:57 pm

Thanks for bringing this up, I have always wondered about them because they look so crude: small rectangular pieces of metal attached along a modern wing. I have wondered (like so other small fins seen on aircraft) why they are just rectangles; no angle to the front or smooth curve.

I realize the air that passes over the entire surface of an aircraft is very critical, anything that is attached that doesn't "look" aerodynamic always makes me wonder. Like the square flat window on the front of a 717 or some of the lights that are attached to the roof of the fuselage that aren't shaped in some aerodynamic way.

Thanks
 
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DocLightning
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 15, 2016 2:21 am

usxguy wrote:
interesting thread.. i guess that explains why I've seen rows of VG's on flaps..

Image


Correct. These 767 flaps are relatively straight and the change in angle is rather abrupt from the main wing. To prevent flow separation at high flap settings, the VGs are placed to energize the airflow and keep it attached.

More modern designs used curved flaps that contour into the wing when retracted. See the A380 as an example:

Image
 
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DocLightning
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 15, 2016 2:44 am

VC10er wrote:

I realize the air that passes over the entire surface of an aircraft is very critical, anything that is attached that doesn't "look" aerodynamic always makes me wonder. Like the square flat window on the front of a 717 or some of the lights that are attached to the roof of the fuselage that aren't shaped in some aerodynamic way.


Aerodynamics doesn't always look the way you think it should. ;)
 
thepinkmachine
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 15, 2016 3:06 am

VC10er wrote:
Thanks for bringing this up, I have always wondered about them because they look so crude: small rectangular pieces of metal attached along a modern wing. I have wondered (like so other small fins seen on aircraft) why they are just rectangles; no angle to the front or smooth curve.



They actually need to be rectangular and low-aspect-ratio (i.e. short and wide) to generate stronger vortices - quite the opposite to eg. wingtips.

I have always been amazed by the simplicity and effectivity of these devices (though, as others said, they are often a patch for some deficiency). There's a good article on smartcockpit.com on how they work:
http://www.smartcockpit.com/download.php?path=docs/&file=Vortex_Generators.pdf
 
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EA CO AS
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 15, 2016 3:29 am

Polot wrote:
Those are vortex generators. They, as the name implies, generate vortexes


Vortices
 
reltney
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 15, 2016 2:02 pm

DocLightning wrote:
usxguy wrote:
interesting thread.. i guess that explains why I've seen rows of VG's on flaps..

Image


Correct. These 767 flaps are relatively straight and the change in angle is rather abrupt from the main wing. To prevent flow separation at high flap settings, the VGs are placed to energize the airflow and keep it attached.

More modern designs used curved flaps that contour into the wing when retracted. See the A380 as an example:

Image


3 types of flaps are used on most planes . Plain, split and fowler.

Plain flap is what you would fine on many small planes. The trailing edge just droops. No aerodynamic shape, just the last 1/4 or so of the wing Is the flap.
Split flap you cannot see from the top of the wing. B-17, spitfire and DC-3 use them. Not really a big lift type flap but effective. Last is the fowler type which is on almost every airliner you see. The 767 and 380 in the photo are both fowler flaps. They BOTH are airfoil shaped. Different angles of photo don't show the whole profile. They are each like little wings. They are a true high lift device. The gap between the wing and the leading edge of the flap allows air to go around the flap acting like a second wing. The flap slides out and down doing 2 things. It increases wing area and curve of the whole wing.
The 747 and 727 have some of the most effective triple slotted flaps. Like adding 3 wings. The 747sp eliminated them as the additional lift was not needed and the 747-800 changed wings so it uses a single slotted flap. The Cessna 150-207 series uses the same single slotted type fowler flap you see In the photo of the 380 and 767. The first settings change the wing area by sliding out a bit before they change angle. The last bit they change angle mainly.

Flaps are fascinating and each is designed to help each airframe to obtain the maximum lift and allowing when retracted to have the least drag and be the lightest system possible.

Cheers
 
OldAeroGuy
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 15, 2016 4:16 pm

c680 wrote:
Vortex Generators - they delay flow separation and improve low speed performance. Small drag penalty for a reduction in stall speed or improved low speed control surface performance.

As aerodynamic designs have improved over the years, these devices are seen less and less, thus more of them on older planes. In many cases, they are added to an aircraft by the manufacture after the plane was designed as a way to fix a problem or improve performance.


VG's are not necessarily applied to improve low speed characteristics. The position of these VG's well aft of the wing leading edge indicates they are for high speed flight characteristics where they delay shock induced flow separation.

While high speed VG's are usually applied to improve high speed handling characteristics, they can also improve cruise drag. 777NG flight testing showed adding outboard wing VG's reduced cruise drag. They were later offered as a cruise drag reduction kit for 777 Classics.
 
AeroVega
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 15, 2016 4:47 pm

EA CO AS wrote:
Polot wrote:
Those are vortex generators. They, as the name implies, generate vortexes


Vortices


Vortexes is fine, too. See http://www.merriam-webster.com/dictionary/vortex.
 
reltney
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 15, 2016 5:26 pm

OldAeroGuy wrote:
c680 wrote:
Vortex Generators - they delay flow separation and improve low speed performance. Small drag penalty for a reduction in stall speed or improved low speed control surface performance.

As aerodynamic designs have improved over the years, these devices are seen less and less, thus more of them on older planes. In many cases, they are added to an aircraft by the manufacture after the plane was designed as a way to fix a problem or improve performance.


VG's are not necessarily applied to improve low speed characteristics. The position of these VG's well aft of the wing leading edge indicates they are for high speed flight characteristics where they delay shock induced flow separation.

While high speed VG's are usually applied to improve high speed handling characteristics, they can also improve cruise drag. 777NG flight testing showed adding outboard wing VG's reduced cruise drag. They were later offered as a cruise drag reduction kit for 777 Classics.




Old Aero Guy who quoted Barns Wallis in his signature is 1000% correct.

First use was the B-47. It was to keep the boundary layer attached to the wing for the aileron at high speeds. Old aero guy can verify.
 
winstonlegthigh
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 15, 2016 5:59 pm

VC10er wrote:
...I have always wondered about them because they look so crude: small rectangular pieces of metal attached along a modern wing...



Image
 
rrlopes
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 15, 2016 6:40 pm

The ERJ has the vortilon, which looks different but has the same intent:
Image

They're the four yellow appendages on the leading edge.
 
reltney
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 15, 2016 8:08 pm

True. The DC-9 series makes good use of the vortilon. It keeps the air flowing around the tail at high AOA
 
phishphan70
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 15, 2016 8:26 pm

winstonlegthigh wrote:
VC10er wrote:
...I have always wondered about them because they look so crude: small rectangular pieces of metal attached along a modern wing...



Image


HOW DID YOU GET HOMER TO TURN INTO KRUSTY!!! This is far more important than the VGs anyway. And, why don't we put speed holes on all of these birds? At lease Concorde must have had them. Does anyone have pictures of those?????
 
spacecookie
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Re: What are these small thin edges on the Boeing 737-800 wing?

Tue Aug 16, 2016 6:30 am

thepinkmachine wrote:
VC10er wrote:
Thanks for bringing this up, I have always wondered about them because they look so crude: small rectangular pieces of metal attached along a modern wing. I have wondered (like so other small fins seen on aircraft) why they are just rectangles; no angle to the front or smooth curve.



They actually need to be rectangular and low-aspect-ratio (i.e. short and wide) to generate stronger vortices - quite the opposite to eg. wingtips.

I have always been amazed by the simplicity and effectivity of these devices (though, as others said, they are often a patch for some deficiency). There's a good article on smartcockpit.com on how they work:
http://www.smartcockpit.com/download.php?path=docs/&file=Vortex_Generators.pdf

That's quite interesting
Thanks
 
winstonlegthigh
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Re: What are these small thin edges on the Boeing 737-800 wing?

Tue Aug 16, 2016 5:06 pm

phishphan70 wrote:
winstonlegthigh wrote:
VC10er wrote:
...I have always wondered about them because they look so crude: small rectangular pieces of metal attached along a modern wing...



Image


HOW DID YOU GET HOMER TO TURN INTO KRUSTY!!! This is far more important than the VGs anyway.

I was taken aback initially by this image when I found it, but IIRC, this is the episode where Homer goes to clown school and is mistaken by the Mob to be Krusty, who owes them money.
 
OldAeroGuy
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Re: What are these small thin edges on the Boeing 737-800 wing?

Tue Aug 16, 2016 8:29 pm

reltney wrote:
OldAeroGuy wrote:
c680 wrote:
Vortex Generators - they delay flow separation and improve low speed performance. Small drag penalty for a reduction in stall speed or improved low speed control surface performance.

As aerodynamic designs have improved over the years, these devices are seen less and less, thus more of them on older planes. In many cases, they are added to an aircraft by the manufacture after the plane was designed as a way to fix a problem or improve performance.


VG's are not necessarily applied to improve low speed characteristics. The position of these VG's well aft of the wing leading edge indicates they are for high speed flight characteristics where they delay shock induced flow separation.

While high speed VG's are usually applied to improve high speed handling characteristics, they can also improve cruise drag. 777NG flight testing showed adding outboard wing VG's reduced cruise drag. They were later offered as a cruise drag reduction kit for 777 Classics.




Old Aero Guy who quoted Barns Wallis in his signature is 1000% correct.

First use was the B-47. It was to keep the boundary layer attached to the wing for the aileron at high speeds. Old aero guy can verify.


I agree VG's were used on the B-47. However, I believe they were applied to cure a high speed pitch up problem (ie stick lightening).

See this article for pictures and text.

http://www.rbogash.com/B47.html
 
phishphan70
Posts: 223
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 22, 2016 9:43 pm

winstonlegthigh wrote:
phishphan70 wrote:
winstonlegthigh wrote:


Image


HOW DID YOU GET HOMER TO TURN INTO KRUSTY!!! This is far more important than the VGs anyway.

I was taken aback initially by this image when I found it, but IIRC, this is the episode where Homer goes to clown school and is mistaken by the Mob to be Krusty, who owes them money.

I brought this up to my friends over the weekend, and they all said, "How do you not remember Homer being mistaken for Krusty and having Ned's bible and extra thick piece of the cross save his life?!?!" Needless to say, I'm more disappointed in myself than I am upset with myself.....

Thinking I may put a few speed holes in my car tonight
 
Wacker1000
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Re: What are these small thin edges on the Boeing 737-800 wing?

Mon Aug 22, 2016 10:22 pm

DocLightning wrote:
c680 wrote:
Second, they are not a way to "fix a problem" any more than flaps are.


On the 737 classic they are - http://www.b737.org.uk/fuselage.htm
 
benjjk
Posts: 395
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Re: What are these small thin edges on the Boeing 737-800 wing?

Tue Aug 23, 2016 6:05 am

phishphan70 wrote:
winstonlegthigh wrote:
phishphan70 wrote:

HOW DID YOU GET HOMER TO TURN INTO KRUSTY!!! This is far more important than the VGs anyway.

I was taken aback initially by this image when I found it, but IIRC, this is the episode where Homer goes to clown school and is mistaken by the Mob to be Krusty, who owes them money.

I brought this up to my friends over the weekend, and they all said, "How do you not remember Homer being mistaken for Krusty and having Ned's bible and extra thick piece of the cross save his life?!?!" Needless to say, I'm more disappointed in myself than I am upset with myself.....

Thinking I may put a few speed holes in my car tonight


Krusty was originally meant to be Homer's alter ego, hence the similar features...

Anyway, aviation aviation..
 
phishphan70
Posts: 223
Joined: Tue Oct 03, 2006 5:23 am

Re: What are these small thin edges on the Boeing 737-800 wing?

Tue Aug 23, 2016 5:43 pm

benjjk wrote:
phishphan70 wrote:
winstonlegthigh wrote:
I was taken aback initially by this image when I found it, but IIRC, this is the episode where Homer goes to clown school and is mistaken by the Mob to be Krusty, who owes them money.

I brought this up to my friends over the weekend, and they all said, "How do you not remember Homer being mistaken for Krusty and having Ned's bible and extra thick piece of the cross save his life?!?!" Needless to say, I'm more disappointed in myself than I am upset with myself.....

Thinking I may put a few speed holes in my car tonight


Krusty was originally meant to be Homer's alter ego, hence the similar features...

Anyway, aviation aviation..

MIND BLOWN!!!! Also, let's remember Marge's father is a pilot..... or so she thought. And, Abe Simpson's done some serious A&P work...
Image
 
greg85
Posts: 204
Joined: Tue Jun 26, 2007 9:45 am

Re: What are these small thin edges on the Boeing 737-800 wing?

Tue Aug 23, 2016 6:05 pm

I just wanted to add one of my favourite phrases to this. "Re-energise the boundary layer".

Thank you.

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