In late 1917, Oscar von Asboth left Fischamend to become a director of the Ungarische Luftschraubenfabrik GmbH, the former propeller manufacturing subsidiary of UFAG. At his own expense, Asboth commissioned UFAG to build a model helicopter followed by a man-carrying version based on the designs he had discussed with Balaban at Fischamend and for which he received Austrian patents 76,184 and 79,539 dated April 1917. His was a four-rotor helicopter tethered by a single cable attached to the airframe by a gimballed yoke that allowed the airframe to move about all axes. The four wooden rotors each had a diameter of 3 meters. Unfortunately, before any tests were run the model version, powered by a French 20hp rotary engine, and the virtually completed full-sized airframe were destroyed in a fire at the UFAG factory on 9 September 1918. Five months of effort had come to naught.
Peter Grosz "Austro-Hungarian Army Aircraft of World War I", 2002