During WWI, there was an immense need for airplane engines, especially on the German side. So a little company called Rapp Motor merged with Otto Werke, an airplane maker just up the street in Munich, combining forces to satisfy the war effort's needs. Otto Werke was run by the son of the guy who made four-cycle engines useable -- which ultimately contributed to just about every car engine on the road. That same technology went directly into the engine that legendary fighter pilot the Red Baron called the greatest engine in WWI.
