Junkers Ju 87 near Sagan, 13 Ju 87s and 26 crew members were lost when they crashed into the ground almost simultaneously. The planes dived through cloud, expecting to release their practice bombs and pull out of the dive once below the cloud ceiling, unaware that the ceiling was too low and unexpected ground mist formed, leaving them no time to pull out of the dive. On 1 September 1939, the Wehrmacht invaded Poland, triggering World War II. "Generalquartiermeister der Luftwaffe" records indicate a total force of 366 Ju 87 A and Bs were available for operations on 31 August 1939. The first
Junkers J 1 a series of fully cantilevered all-metal monoplanes. Upon the outbreak of the First World War in 1914, Junkers decided to direct his efforts towards projects which would have potential military value. During this era, the majority of aircraft designers were relatively conservative and, save for some isolated examples, no advancements were achieved; according to aviation historian Charles Gibbs-Smith, the pioneering work of Hugo Junkers was a notable exception. It was Junkers' efforts, along with those of collaborators such as engineers Otto Reuter, Otto Mader, head of Junkers' "Forschungsanstalt", and Hans Steudel, director of Junkers' structural materials and testing department that