737 fins??

[jet2impress]

Hi,

Is anyone able to tell me what the 'fins' are on some 737's located between the horizontal stabilizer and the rudder? These can clearly be seen in the picture below:

http://www.airliners.net/open.file/759432/L/

Thanks!

[Sky Wave]

At a guess I'd say it was the APU intake/Outlet. The fins are probably a grill which closes when the APU is switched off.

[jet2impress]

Hi,

Its not the APU air intake, its well above the intake above the horizontal stabilizer, next to the rudder. There are 4 of these on either side.

[NWSRG]

What you are looking at are Vortex Generators. You will also see them on the top surface of some wings.

They are used to manage airflow. I'm not sure, but I think in this case, these ones are used to 'clean' the airflow departing the tail of the aircraft, thus reducing drag.

[jet2impress]

Thanks for that NWSRG. I will be able to sleep at night better now! lol