Under the leadership of Mach and Regner, this mock-up and one other had been constructed by June 1939. As of July 1939 more studies were carried out featuring a twin- engined jet aircraft with a nose wheel. At that time the future He 280 was still designated He 180. By late summer 1940 numerous details had been resolved and Heinkel offered the hitherto private project to the Reichsluftfahrtministerium