I was wondering if there is any flight simulator out there that could import a custom made 3D model that i make in a 3D Graphics application.
It would help a lot to test it's flying behaviour inside the computer, and fix any problems, rather than building it for real, just to see it crash.

Real Flight will let you change any perameters for any plane.

You could take say the Cap 232 and change the wing's airfoil, it's length, its chord, where it's placed in relation to the CG and in relation to the thrust line, and do the sme for the horiz and vert stabs, the elevator, ailerons and rudder, the landing gear, etc.

I used the Ultimate Bipe as a platform for a Great Lakes Bipe and it changed the flight characteristics significantly. WHether of not it's accurate I can't say, as I haven't finished the Great Lakes. (The modified plane still looked like the Ultimate though. )

I believe Aerofly Pro will allow some level of modification too.
Dennis-

FMS (flying model simulator) is free and has the ability for you to "build" your own model. The only drawback is you do have to purchase a cable for your transmitter. Mine was $52, shipped.

dano13

FMS is okay as a free Sim, but it lacks a lot of the physics required for realistic simulated flight. But if you wish to go that route, here's a link to a guy that makes and sells the interfaces for $16 shipped, and he includes FMS and extra planes on a disk. (Sorry you spent $52 dano. [])

http://www.mattclement.freeservers.com/fms/fms.html
Dennis-