German experimental aircraft Dornier Do 335 Pfeil is one of the most unusual aircraft of World War II. Recognized as such because of the tandem two engine layout: pulling the screw is on the nose, push – on the tail of the fuselage. Experimental aircraft Dornier Do 335 Pfeil was exceptional in their characteristics, it is the fastest piston aircraft of its time (the maximum speed – 785 km/h). If the Germans were able to solve the technical problems that accompanied the process of developing and testing the aircraft, and to begin mass production Do.335 Pfeil, they would get a very significant advantage in the sky: the fastest fighter-bomber in the world.