I know nothing in this subject, but I have heard that one of the reasons it takes so long to model a new plane, is that they gather contemporary sources, actual data from WW2. For example, to model the BF 109, they read through test data (or what survives of it) for that aircraft, pilots reports etc. It takes a long time to compile the data.
This is just what I've heard though, so I may be waaaay off the mark. But I believe thats the reason for the RV8 being in Game. HT has a real RV8, and he uses the model to tweak the FM in game.