The Junkers Ju 187 was designed to replace the ageing Junkers Ju 87 Stuka (after rejection of the Ju 87F), which by the time of the Battle of Britain had proved very vulnerable to enemy fighters. It kept some of the features of the earlier Ju 87, such as the inverted gull wing and two man crew. The Ju 187 would have added retractable landing gear, as well as improved armour and armament. Most notably, the Ju 187 incorporated a rotating vertical tail. When rotated down, the tail would give the air gunner, armed with a rear turret, an unobstructed field of fire. It is not known how the aircraft would have handled with the tail rotated.The Ju 187 project was cancelled by the Reich Air Ministry in autumn 1943 because the aircraft's projected performance, when fully loaded, was estimated to be no better than the latest Ju 87 D variant (estimated maximum speed: 248 mph (399 km/h)).