737 fins??
 

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!

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.

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.

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.

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