Junkers setbacks with crashes of prototypes in 1937 and 1938. Further refinements enabled certification in 1939 and spurred South African Airways to make an initial order for two aircraft fitted with US-built Pratt & Whitney engines. Just as the aircraft was being readied for its first commercial flights, World War II began. With the outbreak of hostilities, all models were requisitioned by the Luftwaffe for military air-transport roles, and later, long-range maritime patrol. Military aircraft production was begun by the company in the 1930s and eventually monopolized all its resources. Perhaps the most notable design was the Junkers Ju 87 "Stuka"
Junkers J 2 fuselage directly below the stabilizer's leading edge root. The wings had at least three different airfoil changes between root and tip, and had sections of them electrically roll-welded for stronger, more continuous bonding for greater strength. The resulting aircraft was intended to be smaller than the J 1 demonstrator, but with its steel structure, it almost equalled the J 1's completed weight. One feature pioneered in the J 2 that would also be used in later all-metal monoplanes designed and built by Junkers in World War I, was a "unitized" forward fuselage structure, combining the engine mount, wing roots and