The E.500 was a proposed heavy fighter design put forth by Arado Flugzeugwerke of Germany. The system was designed as early as 1936 and featured a crew of four consisting of a pilot, co-pilot, dorsal turret gunner and ventral gun station gunner. The project advanced beyond the design stage as a full scale mock-up was created before the project's eventual cancellation.
Design-wise, the E.500 was to be built around a twin-boom philosophy. The wings were high-mounted, running through each engine nacelle and spanning across the top of the gondola-style fuselage. The pilot and co-pilot were afforded good views outside their aircraft - particularly to the front, above and left and right sides thanks to the position of the cockpit at the extreme forward of the fuselage. The dorsal gunner sat in a seat directly behind the cockpit cabin and controlled a pair of 20mm Rh LB 202 series cannons. His vision was adequate as well. The fourth crewmember would have managed a ventral gun position in the lower part of the gondola. This gunner would lay in the prone position and utilize a periscope for aiming and firing.
Engines were intended to be fitted in the forward portion of the booms. The nacelles would run right into the booms which extended to the extreme aft of the aircraft. The tail booms were not joined but instead given independent elevators and vertical tail surfaces. The engines were envisioned as a pair of Daimler-Benz DB 603 series engines.
In any case, the design was quite ambitious by 1930's standards. It remains to be seen whether this system would have performed well in the intended role of heavy fighter though this author maintains his doubts. With four crew members, heavy armament, an oversized fuselage and large wing area, the E.500 design would have a decent enough time against Allied bombers but would suffer greatly against the more agile fighter types designed in the 1940's.