Junkers Flugzeug- und Motorenwerke AG JFM
Jumo 222 in-line piston engine

The comparison was even more favourable against other high-power engines under development. The cumbersome DB 606, the first-ever "high-output" powerplant developed in Germany, consisted of two DB 601's mounted to a single reduction gear case on their front ends, that delivered 1,790 kW (2,400 hp) with a weight of 1,515 kg (3,340 lb), and was 2.1 m × 1.6 m × 1.1 m (83 in × 63 in × 43 in)ft) in size. Their troubled use and deficient installation design in the He 177A, Germany's only heavy bomber aircraft to see production and front-line service, prompted Reichsmarschall Hermann Göring to derisively label them in the late summer of 1942 as "welded-together engines".^[3] Conversely, the RLM was excited by the possibilities of the much more compact Jumo 222's design features, and the X engine configuration, 24 cylinder DB 604, of similar weight and displacement to the 222A but with somewhat lower specific power output. The RLM based their entire Bomber B program on pairs of these engines, which would deliver a bomber with the warload of the He 177 and even better speed than the Ju 88, a truly universal design.

By late 1941, Junkers decided the best course of action was to make more radical changes to the design, and introduced the 222C and 222D models. With a new bore and stroke of 145 mm × 140 mm (5.7 in × 5.5 in), the engine displacement increased a second time, to 55.5 L (3,386.8 in³), just very slightly larger than the contemporary Wright Duplex Cyclone American 18-cylinder air-cooled radial engine, which at the time was having its own significant problems ironed out, partially from the use of combustible magnesium-alloy metal for its crankcase. Back at the original 3,200 rpm, the Jumo 222 C/D models could deliver just under 2,200 kW (3,000 hp) when they started running in the summer of 1942. However, the problems were not cured, and only a handful were built. The RLM had been waiting for three years at this point, and eventually gave up and had all designs based on it look for alternate engines. Later that year, they gave up on that as well, and cancelled the entire Bomber B program outright.