It was along time ago and I don't have the game any more but from what I remember it was something like this ...
Edit the file f1graphics.cfg using NotePad or WordPad.
Set the first line of this file to '1' (this allows the settings in this file to take effect in-game).
Set the 2nd line to '1920' (or any widescreen horizontal resolution).
Set the 3rd line to '1200' (or any widescreen vertical resolution).
Run the game.
Also ...
The menu system is drawn incorrectly but it is still navigable though.
In-game, while in cockpit view, use the - and + keys on the numberpad to zoom in and out to your preference.
Here is a couple of screenshots of how I used to run it across three monitors using the method above ...
I hope this helps you ... let me know ...
Cheers ... :)