Prototypes, Ju 88 B-0
The prototype Ju 88B V1, D-AUVS, flew for the first time with the 801A/B engines in early 1940. The fuselage was identical to the Ju 88 A-1, which presented a problem: with the extra power, 1,560 PS (1,150 kW, 1,540 hp), the design could now carry considerably more load than the small bomb bay could fit. An additional external shackle was then added to each wing well outside the engines, although using the rack would seriously hamper performance.
During the summer, a pre-production run of 10 Ju 88 B-0 based on the pre-production Ju 88 A-4 airframes were delivered. The A-4 used a longer wing of 20.08 m (65 ft 10½ in) span from new rounded wingtips for better altitude performance, when compared to the initial Ju 88A-1's shorter 18.26 meter (59 ft 10.75 in) span, but attention to streamlining and new "pointed" wing tips, somewhat resembling those fitted to the British Spitfire Mks.VII and VIII for their own intended high-altitude flight requirements, kept drag to about what it was earlier. The airframe changes moved the center of gravity slightly, so the glazed "cockpit" area was made slightly longer to re-balance the aircraft, while also offering better visibility for other members of the crew.
Service tests were all successful, and the pilots generally lauded the new cockpit design. However, the RLM still remained unconvinced that the small improvement in performance over the existing A-5's and future A-4's was worth investing time in. Instead, the pre-production models were modified as long-range reconnaissance aircraft by removing the guns, bombsights and external bomb shackles, and fitting fuel tanks into the bomb bay.
Several of the airframes were retained by Junkers for further development. One of these was fitted with the slightly updated 801L engines and a small power-operated turret on the extreme top of the cockpit mounting a 13 mm (.51 in) MG 131 machine gun.
Read more about this topic: Junkers Ju 188