What purpose do those little fins on the top of the wing serve?

[Snow]

I keep seeing these little fins on the top serface of the wing on airliners, maybe 1in high tops, what are they for?

 

[Eagle]

they are either vortex generators or BLEs, they "Stir-Up the air" so it does not leave the wing as soon. this will reduce the stall speed at High AOAs, and reduce the control surface flutter, increase the MMO as well.

 

[SEAN]

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they are either vortex generators or BLEs, they "Stir-Up the air" so it does not leave the wing as soon. this will reduce the stall speed at High AOAs, and reduce the control surface flutter, increase the MMO as well.

[/ QUOTE ]

BLE? MMO?

 

[Eagle]

BLE
Boundry layer energizers.

everything elses is here

http://www.gps.tc.faa.gov/glossary.html

 

[Minuteman]

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BLE

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Did you ever work around F-4s?

 

[Eagle]

[ QUOTE ]
[ QUOTE ]
BLE

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Did you ever work around F-4s?

[/ QUOTE ]

nope not even sure I cold Identify one from any other fighter jet, not my area of interest.

The learjet use BLEs, (depending on model and ser #)

 

[Ophir]

I have never seen vortex generators on anything but GA planes (not that I have access to many faster planes). Do they use them on many fast planes?

 

[Eagle]

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I have never seen vortex generators on anything but GA planes (not that I have access to many faster planes). Do they use them on many fast planes?

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Sure, (again sorry for not being commercial jet literate) but I have been on a large transport category acft A-300 or MD-80 type that have had VGs right down the wing. I am not so sure the speed is the issue with VGs like it is with BLEs, but it does give you a larger window for useful airspeed. (dropping the VSO raising the MMO,