Complex sentence: It was a private venture by the German Heinkel company in accordance with director Ernst Heinkel's emphasis on developing technology for high-speed flight and first flew on 27 August 1939, piloted by Erich Warsitz.
Split into simpler sentences: It was a private venture by the German Heinkel company in accordance with director Ernst Heinkel's emphasis on developing technology for high-speed flight. It first flew on 27 August 1939, piloted by Erich Warsitz.