Mercedes-Benz MB503 engine

The Mercedes-Benz MB 503 was a German prototype four-stroke V-12 petrol engine for marine and aircraft use, designed and conceived before World War II. It was based on and derived from the Daimler-Benz DB 603 inverted V-12 aircraft engine, which was itself a liquid-cooled 12-cylinder inverted V12 enlargement of the DB 601, a development of the DB 600. The powerplants eventually chosen for the Panzer VIII Maus super-heavy tank were the MB 509 petrol V-12, also derived from the DB 603, and the MB 517 diesel V-12. A diesel variant, the MB 507, was likewise based on the DB 603.