Editor's note: This is the fourth in a four-part series on the Army's Robotic Combat Vehicle program. Forget about the air show and the 1980s kids clothing: The Oshkosh you need to know about is the automaker. Oshkosh doesn’t build passenger vehicles, so the only time you’re likely to run into one on the road is when the post office makes a delivery with the goofiest-looking mail truck of all time . For U.S. service members, there’s more to the story. Oshkosh Defense has built some of the