Quote Originally Posted by denkimi View Post
I don't mean a metal sheet in the door, I mean a 2mm metal plate welded to the rollcage. You can't stop everything because the driver still needs to see outside, but a lot of openings that he doesn't need could be closed way better than they are now.

Even if the comparison is very imperfect because of the penetrator cross section I'll go back to the pistol bullet. It has an energy equivalent to a WRC car moving at only 2 km/h but it can penetrate 4 mm of steel. A car moving at 20 km/h has 86x more energy. What You propose would help just a little and it would bring about 20 kg weight in places which are inconvenient for the vehicle performance.