The Dornier Do 217 was a World War II heavy bomber designed from scratch as a replacement for the venerable Dornier Do 17. Dornier recognized shortcomings of its fast Dornier Do 17 well before the war. With Junker's new Junkers Ju 88 prototype being superior to the Do 17 in every way, Dornier decided to make a new bomber better than its Do 17, and its Ju 88 competition. Superficially a scaled up Do 215, powered at first by the same DB 601 engines, the Do 217 was actually considerably larger and totally different in detail design. Much of Dornier's efforts in 1938-1940 were devoted to finding more powerful engines and improving the flying qualities, and when the BMW 801 radial engine was available the Do 217 really got into its stride and carried a heavier bomb load than any other Luftwaffe bomber of the time. In almost every way, the Do 217 was a success. It could carry much higher bomb loads than either the Ju 88 or the Heinkel He 111. It was also very fast, surpassing the speed of the Ju 88. It was Germany's largest bomber for nearly two years until the Heinkel He 177 was finally safe enough to use. Do 217's sank the Italian battleship Roma with Fritz X missiles as she steamed to the Allies after Italy's capitulation. However, the Do 217 had some quite serious flaws. It was at the limit in terms of size that a twin engined bomber could be with the engines available. Unlike its agile cousin Do 17, this aircraft was more difficult to fly. Stability issues were a problem at first but modifications such as fixed slats along the leading edges of the vertical fins helped to improve flight stability. Like its cousin and Ju 88, it was used in a variety of different variants and roles, including the night fighter, another sign that Germany desperately needed fighters over bombers, something the Ju 88 was better at doing. Production was stopped in late 1943 in favour of fighters.