Junkers Ju 87 with the Ju 87 A-0, the B-1s were returned discreetly to the Reich. The experience of the Spanish Civil War proved invaluable - air and ground crews perfected their skills, and equipment was evaluated under combat conditions. The Ju 87 had not been tested against numerous and well-coordinated fighter opposition; this lesson was learned later at great cost to the Stuka crews. All Stuka units were moved to Germany's eastern border in preparation for the invasion of Poland. On the morning of 15 August 1939, during a mass-formation dive-bombing demonstration for high-ranking commanders of the Luftwaffe at Neuhammer training grounds
Junkers Jumo 213 3700 rpm for take-off. It would have weighed . There was no time to work this change into the production line before the war ended. Other experimental models included the 213S for low-altitude use, and the turbocharged 213T. Further development of the Jumo 213 was carried out at Arsenal de l'Aéronautique in France after the Second World War. Arsenal 24H-Tandem:2x 24H engines in tandem driving co-axial propellers. Junkers Jumo 213 The Junkers Jumo 213 was a World War II-era V-12 liquid-cooled aircraft engine, a development of Junkers Motoren's earlier design, the Jumo 211. The design added two features, a pressurized