Boeing 737 wing question?

[Vfrpilotpb]

On a recent flight to Paris from EGCC, my seat position gave me a view just to the rear of the trailing edge, the a/c was I think a 737/500, what I could not work out was the need for the tiny L shaped additions that seemed to be welded onto the area just backward of the leading edge outboard of the engines, they appeared to follow a radial sort of pattern on the surface of the wing but from my seat I could not be certain, could any one enlighten my mind as to what these pieces do for the wing?

Many regards
PeterRB

[wryly smiling]

Don't know about the radial pattern but they sound like vortex generators,they're thee to re-energise the boundary layer.

[eng1170]

Quite correct - vortex generators, very painful to kneel on when doing inspections!!!!

[cwatters]

They are designed to make the airflow close to the surface of the wing slightly turbulent (energised). This helps it to follow or "stick" to the curved surface of the wing as it moves from leading edge to trailing edge. It a trick frequently used where the wing is very cambered/curved (near the root) and isn't normally needed out near the tip where the camber is less. If the airflow "breaks away" from the surface it increases drag and reduces lift.

[cwatters]

I forgot to mention that they work by being set at a slight angle to the airflow. If you were to look down on them from above you would see the vertical part doesn't point exactly in the direction of flight. eg like this / not like this |

[Vfrpilotpb]

Gentlemen,
Thank you all for your replys, I have read about the boundary layer on A/c wings but always thought, after nearly understanding what I read about it, that it was created by many holes or such things, perhaps you may explain , why is the air better if turbulance is added, is this because it then follows the upper surface profile more readily ?

not quite as confused as I was!


Many regards
Peter B :)

[lunkenheimer]

Yes, that's it. The little plates mix in high energy (fast) airflow with the slow airflow near the wing surface. This improves the airstream's ability to follow the curve of the wing.