Nacelle fins?

[swashplate]

I have noticed on various aircraft (737s, A320s) that the Engine nacelles have small fins attached to them.

What is the purpose of these devices?

Is it to reduce drag (burn less fuel)?

Or are the manufacturer's trying to use the nacelles to provide extra lift?

Possibly to help the aircraft achive extra stability in roll/pitch/yaw?

Or to alleviate loads on the wing that has to carry the engine....??


As usual, I look forwards to fascinating, detailed, informative replies.

Also, to the sarcasm, flaming etc.........

[This message has been edited by swashplate (edited 10 May 2001).]