There must be a way to alter it, but i would agree that it is probably down to the model itself. I would suggest backing up the model and then try altering the max speed in the config files to see what happens. Alhough that would just prolong the time before the bobble starts . And now i think about it not all my models do wobble in overspeed, Dc10 doesnt and my Jaguar and Vulcan just nose over and require lots of trim and elevator to get them level.