Junkers Ju 87 had been ineffective and disorganised, and as a result, "Stuka" losses were mainly due to ground fire. 120 machines, one-third of the Stuka force, were destroyed or damaged by all causes from 10 May to 25 June 1940. For the Battle of Britain, the Luftwaffe's Order of battle included bomber wings equipped with the Ju 87. Lehrgeschwader 2's IV.(St), Sturzkampfgeschwader 1's III. Gruppe and Sturzkampfgeschwader 2's III. Gruppe, Sturzkampfgeschwader 51 and Sturzkampfgeschwader 3's I. Gruppe were committed to the battle. As an anti-shipping weapon, the Ju 87 proved a potent weapon in the early stages of the battle. On 4
Junkers J 2 spin on 23 September 1916 in one of the J 2s, and this event, combined with the substandard climbing performance of the J 2 series of test aircraft, caused "IdFlieg" to withdraw any further governmental support (effectively ending the J 2's contract) for the Junkers firm's advanced monoplane designs until a lighter metal, such as duralumin, was selected for such designs. The first attempt to use duralumin for airframe construction by the Junkers firm was the never-completed J 3 mid-wing, rotary engine-powered, aluminum tubing fuselage single-seat monoplane design, of which only the corrugated sheet duralumin-covered wing structures and "bare" tubular