i figure once i have figured out the torque about the 3 major axes, can i just stick those in a vector and transform it by the (inverse)moi matrix that is determined when a model is converted? linear forces would be compared against mass. i dont want to convert the forces to acceleration immediately, as i still have gravity to consider. frametime pretty much covers the time dimension. accelerations are multiplied by the length of the frame (technically the previous frame) before being added to the momentums. the momentum and angular momentum are also multiplied by the frametime to determining the new position and orientation. so pretty much all i need to do is simplify the forces before doing that.
For the sake of this purpose, gravity is one of the vectors that you should already be taking into account when determining linear acceleration. It just always happens to have uniform direction and no torque effect on a body, so it's an easy addition.
Stuff like velocity dependant air resistance forces in non-standard flight attitude (flying sideways, or belly-first, or backwards), and transition from lift to stall condition would probably be the most challenging things to get right, and that's practically required for any semblance of accuracy for aerobatic maneuvers like sideslips, tailslides, autorotation (spins and flat spins) or negative stalls like the ones you can get in IL-2 when you pitch down and cross the rudder and aileron controls to either direction, depending on the propeller rotation direction, which results in a fairly controllable negative stall, and a negative flat spin which means you're flying the cockpit canopy first, with about -90 degrees angle of attack. It's an excellent maneuver for quick energy bleed, and a purely evasive/aerobatic one. With good timing you can almost make a hammerhead maneuver with some planes, which is all sorts of awesome....
as for fuel, maybe. i kinda also want to also consider ordinance weight. every weapon has a mass value, so i can just look at the number available and multiply. the mass would be added to the ship's dry mass. im not sure how i will modify the moment of inertia based on that though.
Apply a multiplier to the torque to achieve desired effect based on the configuration. That way you would require a pre-determined multiplier table for each possible loadout configuration.
On the other hand that doesn't allow real-time fuel consumption weight loss and such effects. You'll need real time tracking of mass and it's distribution for that, so you can take the model's empty weight as the base value, and then do a simple MOI calculation real-time to see how much each piece of loadout increases the MOI of the total ship. Calculating MOI is not that hard if you just use distance to center of gravity and use a simplified model where each piece of loadout is attached to a single hardpoint in the model.
engine modeling is also something i want to do, have different types of engines or different engine performace in the atmosphere than in space. perhaps by supplying booster fuel or air breathing engines for atmospheric flight that would produce more power than usual, sort of a "launch configuration". performance for air breathing engines would relate to the atmospheric density, speed and other factors.
If I may suggest, make the basic physics work first before you start fiddling with HOW the thrust vector is produced... that kind of thing would be easy to add later on as it doesn't have too much to do with the flight dynamics model.
another idea is to compute recoil forces as well, get that a-10 stall when firing effect. supersonic modeling is one more idea. drag reaches a peak around mach 1.2, then begins to fall at around mach 1.3, because once a shock cone is established, a local wind velocity begins to manifest. i definately want to do this for weapons, since supersonic bullets and missiles slow down too rapidly due to extreme drag, producing a fire backwards effect.
The A-10 doesn't stall when it's firing. At low speed the combustion gases from the gun can end up in the jet engines which can cause an engine flameout or stall, but really, the recoil force of the GAU-8 Avenger is greatly exaggerated - it doesn't notably slow down the jet. Besides, stall is not a condition that depends on air speed, it's only dependant on angle of attack (and wing profile). The reason why slowing down too much can result in a stall is that the lift is a result of airspeed and angle of attack; when airspeed is decreased, angle of attack must be increased to produce the required amount of lift for level flight. If the stall threshold angle is surpassed, then the wing stalls and lift is lost, but stall itself doesn't depend on airspeed.
The rest, though, is interesting. Truely ballistic primaries would be incredibly awesome. I'm just beginning to worry about how many vectors and objects can modern computers handle during one frame time, and how will the collision detection work.