[forcefeedback]
ground_bumps_magnitude1=3800
ground_bumps_angle1=8900
ground_bumps_intercept1=5.0
ground_bumps_slope1=0.48
ground_bumps_magnitude2=1550
ground_bumps_angle2=9100
ground_bumps_intercept2=0.075
ground_bumps_slope2=1.0
crash_magnitude1=1000
crash_direction1=01000
crash_magnitude2=1000
crash_direction2=9000
crash_period2=75000
crash_duration2=2500000

On my part, I researched a few things, mainly about the FF vars.

From the FS2000 SDK, I found the stick shake, Ground shake, gear retract and crash that are configurable in the aircraft.cfg.

After quite a bit of investigation, I think I found other undocumented vars,
namely for machinegun, bullet damage, rocket and bomb release and flak. I havent tested them yet, but I'll post a message if it works.

OTOH, sadly, I came to the conclusion that flight dynamics forces (stiffness w/speed, aileron bounce, etc) are hardwired and that the program makes calls to DirectInput without any variable lookup. (I hope I'm wrong...) I suspect there is a link to individual airplane files (maybe the .air files) For example, the F4U is much stiffer than the F4F in flight.
The search continues...