Delivering all of these requirements in a single airframe demanded much more powerful engines, and all of the Bomber B concepts, at one time or another, relied on the Junkers Jumo 222 engine to deliver this power. Ultimately, the Jumo 222 was a failure in spite of massive effort and several redesigns over a period of several years, with nearly 300 development prototypes produced. No suitable replacement was ever forthcoming, dooming the Ju 288 program, and leaving the Luftwaffe with older bomber designs during the second half of World War II.