At the end of Second World War, the "Luftwaffe"s most critical requirement was for interceptors as the Commonwealth and American air forces pounded German targets night and day. As the bombing effort grew, notably in early 1944, the Luftwaffe introduced a rocket-powered design, the Messerschmitt Me 163 "Komet", in the very-short-range interceptor role. The engine allowed about 7 minutes of powered flight, but offered such tremendous performance that they could fly right by the defending fighters. The Me 163 required an airbase, however, which were soon under constant attack. Following the Emergency Fighter Program, the Germans developed even odder designs, such as the Bachem Ba 349 "Natter", which launched vertically and thus eliminated the need for an airbase. In general all these initial German designs proved difficult to operate, often becoming death traps for their pilots, and had little effect on the bombing raids. Rocket-boosted variants of both of Germany's jet fighters; the Me 262 in its "C" subtype series, all nicknamed "home protector" ("Heimatschützer", in four differing formats) and the planned He 162E subtype, using one of the same BMW 003R turbojet/rocket "mixed-power" engine as the Me 262C-2b "Heimatschützer II", but were never produced in quantity.