The High-speed Heinkel He 70 Mail Airplane
This is a 1934 NACA technical memorandum on the Heinkel He 70 mail airplane, issued by the National Advisory Committee for Aeronautics for aeronautical engineers and researchers. Its pictures are plain black-and-white photographs of the aircraft: a test run on the ground, the fuselage interior, the pilot's cockpit, and the landing gear strut with wheel hub retracted, paired with a graph of flying speed against horsepower at constant pressure heights, useful to a designer wanting period aircraft detail and technical plotting.
