During the late 1920s, von Opel had undertaken a variety of publicity stunts involving rocket-powered vehicles, Opel-RAKs, for the Opel company. He was assisted in these endeavours by pyrotechnics manufacturer Friedrich Sander and rocketry advocate Max Valier. In June 1928, he had purchased an Alexander Lippisch-designed sailplane, the Ente, and fitted it with rockets.