Sorry, Veltro. I accidentally delted your last post while posting a response.
Anyway, the basics of FM creation are rather straightforward. You could begin by computing the CL, CLa, mac, and Ymac (coefficients of lift and mean-area chords) values for the aircraft you're modeling. Kreelin has created a useful applet that will perform this for you. He's christened it, "AeroConvert".
All one needs to get started is to obtain the following data:
1.) The wing surface area (in meters squared)
2.) Wing chord at the centerline root (in meters)
3.) Wing chord at the wing tip (in meters)
4.) Leading-edge sweep angle (in degrees)
5.) Standard Mach level from which to derive values (TK uses Mach 0.40)
You then still need to figure out the drag coefficients and their associated tables, the various lift tables, etc.
Then comes the detective work, where you must obtain information either from flight manuals for the model in question, or from (hopefully reliable) anecdotal sources. Information that will answer questions such as these:
1) At what point does the real aircraft first begin to exhibit stall buffet?
2) At what point does the stall-induced drag begin to exceed lift?
3) At what point will the aircraft depart from controlled flight (with zero stores)?
Keep in mind that we're just scratching the surface, here.
PM me if you need a hand....