Junkers Ju 87 at night to drop flares and fragmentation bombs, inspired the Luftwaffe to form its own "Störkampfstaffeln" (harassment squadrons). On 23 July 1942, Junkers offered the Ju 87 B-2, R-2 and R-4s with "Flammenvernichter" ("flame eliminators"). On 10 November 1943, the RLM GL/C-E2 Division finally authorised the design in directive No. 1117. This new equipment made the Ju 87 more difficult to detect from the ground in darkness. Pilots were also asked to complete the new "Blind Flying Certificate 3", which was especially introduced for this new type of operation. Pilots were trained at night, over unfamiliar terrain, and forced to
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