The Ar 234C was equipped with four BMW 003A engines, mounted in a pair of twin-engine nacelles based on those from the eighth Ar 234 prototype. The primary reason for this switch was to free up Junkers Jumo 004s for use by the Me 262, but the change improved overall thrust to nearly 3.2 tonnes (7,040 lbf) with all four BMW jets at full takeoff power, especially useful for takeoff and climb-to-altitude performance. An improved cockpit design, with a slightly bulged outline for the upper contour integrating a swept-back fairing for the periscope, also used a much-simplified window design with far fewer glazing panels (8 in total), than the total of 13 separate glazing panels of the Ar 234B cockpit — itself taken almost unmodified in form from the eight A-series "trolley-skid" prototypes — for ease of production. The quartet of BMW jet engines gave the C-series Ar 234s an airspeed that was found to be about 20% higher than the twin-Jumo 004 equipped B series airframes, and the faster climb to altitude meant more efficient flight and increased range.