Junkers Ju 188 - Background

Background

In 1936, Junkers submitted proposals for the Ju 85 and Ju 88 into competition for the new standardized Luftwaffe high-speed tactical bomber, known as the Schnellbomber (fast bomber). The two designs were almost identical, differing only in that the Ju 85 used a twin-rudder and the Ju 88 a single fin. At the same time, they offered modified versions of each as the Ju 85B and Ju 88B, again similar to the original designs, but using an "egg shaped" stepless cockpit forward fuselage design that was essentially one large window, another example of the "bullet-nose" design philosophy that almost all new German bomber designs exhibited from the time of the Heinkel He 111P onwards. The new nose design for the Ju 88B also tightly integrated the forward end of the undernose Bola ventral gondola defensive gun position into the newer nose design, when compared to the "added-on" Bola unit pioneered on the Ju 88 V7 prototype and standardized on the Ju 88A, which offered the Ju 88B somewhat lower drag, and better visibility. At the time, this was considered too radical, and eventually the Ju 88A with its simpler fighter-like "stepped" cockpit won the contest.

By 1939, the original Ju 88 had itself evolved with considerably more window area, but in a fashion that was not well streamlined, with a "beetle's eye" faceted bombardier's glazed nose, and a well-framed two-part "greenhouse" canopy for the cockpit, the two assemblies of well-framed cabin glazing separated by the sheetmetal of the upper fuselage nose. The Reich Air Ministry (RLM) was in the process of ordering a "second generation" bomber in a project known as "Bomber B", but this was extensively delayed due to the non-delivery of the large 2,500 PS (1,840 kW, 2,470 hp)-class engines, like Junkers' own Jumo 222 inline engine, that the designs would rely on. Although Junkers' own Ju 288 was currently leading the contest, there was no delivery date on the engines and the Ju 88B project was re-submitted as a stop-gap measure. For this version, they used the latest short-wing Ju 88 A-1 airframe as a baseline with the new stepless cockpit design, but added the new Junkers Jumo 213 engine, which had recently started bench testing and was expected to deliver 1,500 PS (1,100 kW, 1,480 hp). The Reichsluftfahrtministerium (RLM - Air Ministry) also stipulated that the aircraft should also be able to accept the BMW 801 radial engine in a Kraftei (power-egg) unitized installation, with no modification to the existing engine nacelles.

The RLM was not impressed with the new design, as it offered only small improvements over the existing Ju 88A model then in service. However, they did suggest that Junkers continue with the prototype work anyway, but asked that they consider fitting the design with the BMW 139 radial instead. This engine was cancelled only a few weeks later, and all designs based on it moved to the newer and more powerful BMW 801.