. Prof. Ahlborn had published a paper in 1897, in which he had described the flying seed of
Zanonia macrocarpa. Etrich and his co-worker Franz Xaver Wels designed an unmanned glider of similar form and flew it successfully in 1904. Attempts to add an engine failed, but a successful manned glider was flown in 1906. He also worked with Karl Illner. The next stop was Vienna, where Etrich had his second laboratory in the
Wiener Prater at the
Rotunde. In 1907, he built his Etrich I, the
Praterspatz (
Prater park Sparrow) there. Due to its low power () of the engine and the limited space for flying, the aircraft was unsuccessful. In 1909, the first airfield in the Austro-Hungarian Empire was founded in
Wiener Neustadt. Etrich rented two hangars and continued to develop his design, the
Taube (
Dove). Meanwhile, Wels visited Paris to study the aircraft of the
Wright brothers and split with Etrich over the question of whether to build a
monoplane or
biplane. In 1910, the Etrich II, or
Taube, made its maiden flight. In an early flight, Etrich nearly broke his back when it crashed. From then on, Karl Illner made all of Etrich's test flights. Etrich continued to refine the
Taube so as to meet the specifications of the military, which included the requirement to be able to land on a freshly plowed field. In 1912 he founded
Etrich Fliegerwerke in Liebau (today
Lubawka, Poland) and designed an aircraft with an enclosed cabin for the passengers, which he named
Luft-Limousine. Later he moved to Germany, founding
Brandenburgische Flugzeugwerke, which became
Hansa-Brandenburg after he sold it to
Camillo Castiglioni in 1914. From Liebau, Etrich took his chief designer,
Ernst Heinkel, with him. Another aircraft designer,
Edmund Rumpler, modified the design of the
Taube slightly, claimed to be the developer and refused to pay licensing fees to Etrich. With the advent of
World War I, Etrich made the design for his
Taube freely available and dropped his lawsuit. After World War I, Etrich moved back to his birthplace
Trautenau (now Trutnov) in the newly founded
Czechoslovakia, and built the
Sport-Taube. It was claimed to be faster with its 40 hp engine than the Czechoslovak military planes of the time. The authorities claimed he built the plane for smuggling and impounded his plane. Igo Etrich was so disappointed, that he abandoned his aeronautical projects and dedicated himself to the production of
textile machinery. Etrich died on February 4 1967 in
Salzburg,
Austria. == Surviving aircraft ==