Twin v single fin
 

The answer to this is probably obvious to you guys but us mere mortals can only wonder, why is it that the Americans seem to prefer a twin fin design for their interceptors/fighters F15,17,18,19,22,35,117 etc wheras the Europeans seem to prefer a single fin (albeit a large one) what are the advantages/disadvantages of each configuration?

Maybe its so they fit under the decks of the aircraft carriers better.

That and possibly handling.. It might well also reduce the size of the actuators to power them by having two smaller surfaces over one big one, I suppose in a combat situation you also have a certain amount of redundancy built in by doubling up on them.

On WW2 aircraft like the Lancaster it was to put the rudders in the propwash of the inboard engines, the accelerated air over the rudders and fins meant that you had rudder authority at lower speeds on take off etc and improved handling, as well as reducing the control surfaces size from a single item.

There was a thread in Tech Log a while ago on this very subject - I can't find it just now but if you search you should come across it. Interesting discussion which should give you various answers.

Smithy

Along with preceeding valid points......

probably helps keep the radar signature down a bit having 2 smaller.

Deffo keeps the gun target size down a bit on a fighter.

You need to provide the required keel surface, may as well try to keep it compact