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 span from new rounded wingtips for better altitude performance, when compared to the initial Ju 88A-1's shorter 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.