First semi-controlled flight of the 1919 Berliner machine
Thursday, June 10, 1920 - College Park Airport, Maryland, United States of America
This was a co-axial machine, only capable of brief semi-controlled hops. The machine was piloted by Henry Berliner.
The machine was originally built in 1919 and had flown on Nov 11, 1919 (FLIGHT May 12, 1921, Page 332). Vertical stabilizing fins and rudder were then added on this machine to provide a rudimentary form of control.
Source: The Berliner Vertical Lift Aircraft 1919-1924, J. Gordon Leishman, VERTIFLITE Spring 2002, Page 31