Dude, try www.x-plane.com

You can download a demo version that will allow you to play for 5 minutes. Very, very realistic dynamic flight modeling. Comes with a plane designer that will let you do anything imaginable to create any plane with any engine you would like, down to very small rc planes. This simulator is no microsoft flight simulator, as the matter of fact it has just been approved by the FAA as a pilot training tool. The flight modeling is based on "blade element theory" dont know exactly what that is but it works very good! Not to mention some cool eye candy features.

Take care
Andy