A big part of when I design physics for cars is using lift coefficients and Z positions along the wheelbase to estimate the downforce on each axle. This works fine for rF1 cars, and I'm getting results that make sense, and feel like they're correct while driving too. But it's not really working when I try it with info in some of ISI's HDVs, namely the FR3.5 and FISI2012. As these estimates suggest that the downforce is about 60% on the front with default setups (HDF on the FR3.5). Which looks wrong, and doesn't feel like it at all when driving these cars. One thing that caught my attention in particular is FWCenter on these two cars. FWCenter Z is -1.4 on the FR3.5, and -1.51 on the FISI2012. And this seems like way too much, as that'd put the front wing center of lift more than a meter in front of the front axle. Has something changed in how the center of lifts are specified? Or is there something adjusting the aero balance on these cars I'm not aware of?
Don't have those mods installed right now to check, might be worth seeing if they've implemented the lines near the bottom of this page (I suspect not, but hey...): http://rfactor.net/web/rf2/devscorner/introduction-to-physics-tool-ptool-and-flexible-chassis/ which allow you to define how the aero is distributed front and rear. Other than that I haven't done a lot of testing, for a mod based on the FISI2012 I moved the FWCenter to a more reasonable value and had to bump up the front aero to compensate as you'd expect.
They don't have anything like that, no. They're still on the old PhysicalModelFile implementation. But I figured out what the problem is. Drag caused by various aero parts causes a backwards torque, which fully accounts for the disparity I got. I always assumed this was negligible, but it really isn't! My mistake...
