Out of the life of the inventor Dipl.Ing- Walther Filter, born 15.3.1902 - died 9.4.1980
The idea of flying without an engine, using only muscle power, fascinated him from an early age. He certainly pursued all kinds of experiments and developments in this visionary form of flight. Gustav Lilienthal was probably an important role model for him. Otto Lilienthal's brother researched this until his death in 1933.
Filter's first experiments in Berlin with self-made wing springs and wing joints already promised success. The winged flight of the bird must also be possible tob e conducted by humans... In 1937, the young graduate engineer joined Lufthansa's test flight department as a flight engineer.
The end of the war and the absolute ban on German aviation imposed by the victorious Allied between 1945 and 1950 could not prevent Walther Filter from secretly continuing his calculations and design drawings.
From 1950 to 1955, together with his sons and a small group of experts, he built the prototype of the swing-wing aeroplane in a tightly sealed DAHM & KRUEGER warehouse in Badenstedt/Hannover.
Exhibition use
At the first German Aviation Show in Langenhagen/Hannover, the completed swing-wing aeroplane is presented to the public; the trade press reports with interest. Filters sons have obtained their flying licences; everything is ready for the first take-off and practical flight tests. But even before the SCHWAN is allowed to feel the air under its wings for the first time, it crashes in the maelstrom of German bureaucracy.
No take-off authorisation
No office at the aviation authority is responsible for this type of propulsion! An aircraft with a ‘wing drive’ is simply not a glider. And an aeroplane with its own propulsion, ‘but without an engine’, is not a powered aircraft either... And neither is a helicopter... Well, so instead of a take-off authorization, there is a hefty back tax payment (the reasons for this are concealed in the documents), which stifles the project. Attempts to secretly take the aircraft abroad for flight testing fail. And so the SCHWAN is stored away and preserved.
Filter's younger friend, aviator and fellow campaigner, Paul Ullrich from Celle, took up the ageing inventor's ideas and promised him on his deathbed that he would make the SCHWAN fly. From 1975, he continued to work on it, using more modern and lighter materials and incorporating new ideas into the restoration. A fire in the SCHWAN's warehouse set back the efforts of Ullrich and his flying students from the Arloh/Celle Flying Club by years. In 1995, Paul Ullrich also died and the project was cancelled. For 10 years, the result of visionary ideas and great craftsmanship disappears into a barn. At the beginning of 2000, the heirs of the two inventors donated this extraordinary prototype in its current form to the Hannover-Laatzen Aviation Museum, where it can be viewed today.
Experimental glider swing-wing rotorcraft SCHWAN I, technical data:
Year of construction 1954 - 1957, further developed from 1975 - approx. 1985
Fuselage length 5.20 m
Wingspan 13 m
Flying weight approx. 285 kg
Wing loading 18 kg/sqm
