Well, if you have an mdl file, you're done!
I'm gonna explain how to get it into FS, in case you don't already know. I'll go over most everything, since I don't know what you already have learned!
Just take a look at the setup of other FS aircraft folders. Inside each folder (the default b737_400, for example) you'll find some other folders:
model
sound
panel
texture (several of these, labled with numbers)
And two other files:
aircraft.cfg
Boeing737-400.air
These are the basics for the aircraft folder. There are other files which you can add in, but they are unimportant.
Take a look in the "model" folder. You should see this:
B737_400.mdl ------> the *.mdl file that gmax creates
model.cfg ------> the configuration file that tells FS what to do with the model file.
For making your own aircraft, try this:
Create a new folder in the "aircraft" folder of FS. Name it something similar to your plane.
Create the list of folders inside it, just like it is listed above.
Here's the tricky part: you'll need an airfile and aircraft.cfg file, but since you created your own aircraft, there isn't going to be one in the FS files that exactly matches your model (this is important). So go find an aircraft of about the same size, weight, etc and copy the "aircraft.cfg" file and the airfile (the one with *.air at the end) and paste them into your new folder along with the model folder, etc.
To make them unique to your aircraft, open up the aircraft.cfg (with notepad) and check out the first section. From the 737-400:
Quote:[fltsim.0]
title=Boeing 737-400
sim=Boeing737-400
model=
panel=
sound=
texture=
kb_checklists=Boeing737-400_check ------> DELETE THIS INFO
kb_reference=Boeing737-400_ref ------> DELETE THIS INFO
atc_id=N737Z
atc_airline=American Pacific
atc_flight_number=1123
ui_manufacturer=Boeing
ui_type="737-400"
ui_variation="American Pacific Airways"
description="One should hardly be surprised that the world's most prolific manufacturer of commercial aircraft is also the producer of the world's most popular jetliner. The 737 became the best-selling commercial jetliner worldwide when orders for it hit 1,831 in June 1987 (surpassing Boeing's own 727 as the previous champ). However, it wasn't always that way\s in the first few years of production, there were so few orders that Boeing considered canceling the program. They didn't, and the airplane has more than proven itself in over three decades of service." ------> DELETE THIS INFO
Everything in red above must be changed.
Title= Change this to something you want your aircraft to be known as in FS.
sim= This is the name of the airfile in the folder. Don't alter this just yet, we'll come back to it.
ui_manufacturer= This is how FS displays its categories. Type in an existing one, or just make one up. This is the name you will search for in FS when you want to fly this aircraft.
ui_type= Same as above, just the next step down.
ui_variation= Again, same as above, just the variation type.
We're almost done!
Now save and close that file.
Click on the airfile that is in the same folder. Change the name to something close to what your aircraft is called.
Okay, this is the important part: go into the aircraft.cfg and change the line that we skipped before (sim=) to the same name as the airfile. If your airfile is named bogey.air, then the line should read:
sim=bogey
That's it! Just save and exit and you should be able to see your aircraft in FS!
But there is more to it. Since your aircraft is entirely different from the one you copied the airfile and aircraft.cfg from, you will have to edit the aircraft.cfg to fit. I'll cover this once you've gotten through the steps above.
Good Luck! 8)