On the Flying Qualities of Otto Lilienthal's Large Biplane

The paper describes full-scale balance tests, which have proven structural integrity and longitudinal static stability of an authentic replica of Otto Lilienthal's Large Biplane glider. In addition to that the replica, built after patent drawings, photographs and textual descriptions by the Otto-Lilienthal-Museum, was towed using a rope winch and finally flown downhill without rope or guide wires. The tests allow for the assessment of the aircraft's controllability and stability not only during steady flight, but also during take-off, landing, and on the occasion of wind gusts. A brief description of the design parameters and applied methods is given along with force and moment data gained from balance measurements as well as the evaluation of a limited set of data acquired during flight, including speed, duration, and distances flown